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Childcare vs Second Income Calculator

Judges a second income on what it actually leaves after the taxes it alone attracts, the childcare it makes necessary and the costs of going to work, with the dependent care credit or a dependent care FSA priced from the 2026 schedule rather than at its headline rate, and then reports the weekly childcare cost and the salary at which the job stops paying. Use it when one earner is deciding whether a job is worth taking or keeping while children are in paid care.

Last updated

Calculator overview

Inputs and outputs

This summary comes from the calculator's published input and output contract.

Inputs

Sibling Discount
When omitted Blank
About this input

How much comes off the SECOND AND LATER children, not off the whole bill. The two readings differ by about a factor of two, and only this one reproduces the published two-child rates: a quoted two-child rate of 585 a week against 332 for one child is a 24 percent discount on the second child and a 12 percent discount on the total. Leave it empty and every child is charged in full.

Unit fraction Default Not set Range 0 to 0.3
Second Income (required)
About this input

The salary being judged, for a year and before any tax. Which of two earners you call the second is a choice rather than a fact: the arithmetic is the same either way, and what it means is that this income is the one stacked on top, taxed from the household's existing bracket upward. Enter the gross figure an offer or a payslip states.

Unit $/year Default 60760 Range 0 to 2000000
Salary Growth
When omitted Blank
About this input

How fast this salary rises each year. It compounds the retirement contributions and it is the whole of the raises figure. Leave it empty and the calculator uses the published rate of increase in median full-time earnings, three percent. Setting it to zero says the salary never rises, and then no raises are forgone.

Unit fraction Default Not set Range 0 to 0.08
State Rate
When omitted Blank
About this input

A single flat rate for state and local income tax, charged on the second income alongside the federal rate. Leave it empty if there is no state income tax where you live, which is the case in nine states, and the calculator charges none. It is a stand-in for a schedule rather than a schedule, so a state with its own brackets or its own childcare credit will not be reproduced exactly.

Unit fraction Default Not set Range 0 to 0.133
Years
When omitted Blank
About this input

How far ahead the two long-run figures look. Leave it empty and the calculator uses the horizon the career-gap research works over, which is ten years, a figure an expert can change. It has no effect on what the salary leaves this year.

Unit years Default Not set Range 1 to 18
Work Costs Monthly
When omitted Blank
About this input

What going to work costs each month beyond childcare: commuting, parking, meals bought out, clothes for work. There is no published average for this, which is why it is asked for rather than assumed, and leaving it empty counts none of it. Twenty round trips a month by car is about 240 at published per-mile costs.

Unit $/month Default Not set Range 0 to 1000
Weeks Of Care (required)
About this input

How many weeks in the year you are charged for care. This is not the same as the weeks worked. A full-time place is usually paid for about fifty weeks whether or not the child attends, holidays included, while school-year care such as an after-school sitter is about thirty six. Getting this wrong moves the answer more than almost anything else on the sheet.

Unit weeks Default 50 Range 0 to 52
Retirement Pct
When omitted Blank
About this input

The share of this salary going into a retirement plan. It is used only for the long-run figure, not for the year: contributions are money saved rather than money spent, so they are not subtracted from what the salary leaves. The published average is about 7.6 percent of pay. Leave it empty and nothing is assumed to be put away.

Unit fraction Default Not set Range 0 to 0.25
Employer Match Pct
When omitted Blank
About this input

The share of this salary the employer adds to the same plan. It is pay that only exists while the job does, which is the reason it belongs in a decision about leaving work. The published average is about 4.7 percent. Leave it empty and no match is counted.

Unit fraction Default Not set Range 0 to 0.1
Children In Care (required)
About this input

How many children need paid care because of this job. It sets the childcare bill and it sets the expenses the dependent care credit will count, which stop rising after two children: a third child costs money and earns no further credit.

Unit count Default 1 Range 0 to 6
Childcare Weekly (required)
About this input

What care for ONE child costs for one week, as a provider quotes it. Where more than one child is in care, the second and later children are charged this same rate less the sibling discount. The figures beside the input are survey averages for the common kinds of care and are meant to be replaced by the figure you are actually quoted.

Unit $ Default 332 Range 0 to 2000
First Income (required)
About this input

Everything else the household earns in a year before tax. It is not taxed again here; it is what decides the rate the dependent care credit is paid at, because that schedule reads household income, and it is why the same salary can be worth noticeably less to a higher-earning household.

Unit $/year Default 72380 Range 0 to 2000000
Relief Type (required)
About this input

Which route the childcare is relieved through. The dependent care credit pays a percentage of capped expenses, and the percentage falls as household income rises. A dependent care FSA instead takes the money out of pay before tax, so it saves income tax, state tax and payroll tax together, which for most two-earner households is worth more. Choose None to see the salary with no relief at all. The two routes cannot be counted on the same dollars, so the calculator prices one of them.

Default Dependent care credit Allowed Dependent care credit, Dependent care FSA, None
Marginal Rate (required)
About this input

The federal rate the household pays on its next dollars of income, not the average rate it pays overall. A second income sits on top of the first, so every dollar of it is taxed at that rate or higher, and using an average rate makes a second salary look considerably better than it is.

Unit fraction Default 0.22 Range 0 to 0.37
Investment Return
When omitted Blank
About this input

What the retirement money earns each year. Leave it empty and the calculator uses the real return the career-gap research assumes, four percent. It is a real return rather than a nominal one, so the answer is in today's spending power; using a nominal return instead gives a larger figure in future dollars that buys the same amount.

Unit fraction Default Not set Range 0 to 0.12

Outputs

Table1 Gain Column Input
About this output

Machinery, and NOT an input. The same for the column axis: Excel substitutes into it while filling the grid, and the rest of the time it mirrors Childcare_Weekly.

Unit currency
Table1 Gain Corner
About this output

Machinery. Excel requires the quantity being tabulated to sit in the grid's top-left corner, where it means nothing to a reader, so it is formatted away. It holds Net_Annual_Gain.

Unit currency/yr
Table1 Gain Column Axis
About this output

The values across the top of the grid: the weekly cost of care for one child, in steps of fifty either side of yours and never below zero. Read a column to hold the cost of care fixed and vary the salary. The middle entry is your own figure.

No unit declared
Relief Value
About this output

What the route you chose is worth in money this year. For the credit it is the rate applied to the capped expenses; for the FSA it is the sheltered amount multiplied by the marginal, state and payroll rates together. It is added back to what the salary leaves, so it directly moves both break-even figures.

Unit $/year
Retirement Value
About this output

What the retirement contributions and the employer match this job funds would be worth at your horizon, with the contribution rising at the salary growth and the balance compounding at the return you give. It is reported separately from the year's figures on purpose: it is money put away rather than money spent, so it is never netted against what the salary leaves.

Unit $
Taxes On Second Income
About this output

Every tax this income alone attracts: federal tax at the household's marginal rate, any state rate you entered, and payroll tax at 6.2 percent up to the Social Security wage base plus 1.45 percent on all of it. It is not the household's whole tax bill, and it is not reduced by any deduction, because the figure being measured is the extra tax the second income causes.

Unit $/year
Work Costs Annual
About this output

The monthly cost of going to work, taken twelve times. Zero unless you enter something, because no reliable published average exists for it.

Unit $/year
Table1 Gain Values
About this output

The body of the grid: what the second income leaves for the year, recomputed for every combination of the two axes. One hundred and twenty one cells, each one the whole calculation run again including the credit rate, which changes down the grid because the household income does. It is a component of the grid rather than a result on its own.

Unit currency/yr
Table1 Gain Row Axis
About this output

The values down the left of the grid: the second income, in steps of five thousand either side of yours and never below zero. Read a row to hold the salary fixed and vary the cost of care. The middle entry is your own salary.

No unit declared
Table1 Gain Row Input
About this output

Machinery, and NOT an input. Excel substitutes each value from the row axis into this cell while it fills the grid; the rest of the time it mirrors Second_Income. Change Second_Income, never this: the axis is derived from it, so editing the mirror moves the axis while the grid is being filled and the whole grid comes out meaningless.

Unit currency/yr
Credit Rate
About this output

The percentage the dependent care credit is actually paid at for this household income. It reads zero unless the credit is the route chosen. Most two-earner households are far below the fifty percent headline, because the first threshold is low and is not doubled on a joint return; above the second threshold the rate falls again to twenty percent, which caps the credit at 600 for one child.

Unit fraction
Hourly Net
About this output

What the year leaves divided by a full-time working year of hours. It is the figure that makes a second income comparable with an hourly rate, and it is usually a good deal lower than the one on the payslip.

Unit $
Breakeven Salary
About this output

The salary at which the kept share of a dollar exactly covers the childcare and the work costs, net of the relief. Below it the job costs money. It charges the full payroll rate on the whole salary, so for a salary above the Social Security wage base it is slightly high, and the status line says so when that applies.

Unit $/year
Annual Childcare
About this output

The whole childcare bill for the year, every child, after any sibling discount and before any relief. It is the weekly cost multiplied by the weeks you are charged, so a change to the weeks moves it proportionally.

Unit $/year
Breakeven Childcare Weekly
About this output

The weekly cost of care at which this salary would leave exactly nothing, everything else held where it is. Above it the job costs money. It is computed with the relief as it stands now, so at a very different childcare cost the relief itself would change a little and the true crossing moves with it.

Unit $
Net Monthly Gain
About this output

The same figure divided by twelve, which is the form most household budgets are kept in. It moves with everything above it and carries the same sign.

Unit $/month
Raises Forgone
About this output

How much more the salary earns over the horizon because it rises each year, compared with the same salary held flat. It is the raises alone and nothing else. It is not the lifetime cost of leaving work, which the published research puts at two to four times a salary for every year out and which counts things this calculator does not compute.

Unit $
Net Annual Gain
About this output

What the second income leaves for the year once it has paid its own taxes, the childcare it makes necessary and the costs of going to work, and once the relief has been added back. A negative figure is a real answer rather than a fault: it says the job costs more than it brings in this year, which is what the break-even figures are there to quantify.

Unit $/year
Kept Share
About this output

How much of every dollar of this salary survives to the end. It is the single most comparable figure here across different salaries, because it is not affected by the size of the salary itself except through the tax and the fixed childcare bill. It reads zero when there is no salary to take a share of.

Unit fraction
Model Status
About this output

Reads OK, or explains why the inputs are not valid, or why the answer deserves a second look before you act on it.

No unit declared
This page is provided by LogicCommons for informational purposes only. Results are model outputs computed from the inputs you supply and are not financial, investment, tax, accounting, or legal advice, and no advisory relationship is created. Verify all inputs and results independently before relying on them in any decision.

LogicCommons is in beta. If a result, label, or reference looks wrong, tell us here; we read every message.

Methodology

Purpose and model boundary

Use this to see what a second salary in a household with children actually leaves. The salary is followed through the tax it alone attracts, the childcare it makes necessary, and the costs of going to work, with whatever relief you claim for the childcare added back. What is left is the answer, and it can be negative.

It measures the EXTRA tax the second income causes, not the household's whole tax bill, so the figures here will not reconcile with a return. It prices one year at the childcare bill you enter, and reports two further figures, the raises the job earns over a horizon you choose and what the retirement money it funds would be worth, separately, because those are money put away rather than money spent.

Career effects beyond the raises are outside it. Published research puts the lifetime cost of leaving work at several times a salary for every year out, and none of that is computed here.

Inputs and units

Input Unit Accepted range What it means
Second Income $/year 0 through 2,000,000 The salary being weighed up, before tax. Every figure on the page is measured against it.
Marginal Rate % 0% through 37% The federal rate the household's next dollar is charged at. The second income is taxed at this rate throughout, which is what makes it the extra tax the job causes rather than an average over the household.
State Rate % 0% through 13.3% Optional. A single flat percentage on the second income, and a stand-in rather than any state's rules. Leave it blank where there is no state income tax.
Children In Care count 0 through 6 How many children are in paid care because of this job.
Childcare Weekly $ 0 through 2,000 The cost of care for ONE child for one week, before any sibling discount and before any relief.
Weeks Of Care weeks 0 through 52 How many weeks a year the care is actually paid for. Term-time-only care is far fewer than fifty-two, and the difference moves the bill proportionally.
Sibling Discount % 0% through 30% Optional. The reduction a provider gives for each child after the first.
Relief Type list Dependent care credit, dependent care FSA, None How the childcare cost is relieved. The credit is a percentage of capped expenses that falls as household income rises; the workplace account shelters a fixed amount from federal, state and payroll tax instead. Choose None if neither is available.
First Income $/year 0 through 2,000,000 The other earner's salary. It is here because household income, not the second salary alone, is what the childcare credit is read at.
Work Costs Monthly $/month 0 through 1,000 Optional. What going to work costs each month in travel, parking, meals and anything else that stops when the job does. There is no reliable published average for it, so it reads nothing until you enter something.
Retirement Pct % 0% through 25% Optional. The share of the second salary paid into a retirement plan.
Employer Match Pct % 0% through 10% Optional. The share of the second salary the employer adds to that plan.
Years years 1 through 18 Optional. The horizon over which the raises and the retirement money are valued.
Salary Growth % 0% through 8% Optional. How fast the second salary rises each year over that horizon.
Investment Return % 0% through 12% Optional. What the retirement money is assumed to earn over the same horizon.

Governing relationships

The second salary is reduced by three things and increased by one.

The taxes it attracts are the federal marginal rate on the whole of it, any state rate entered, and payroll tax: the Social Security share up to the wage base and the Medicare share on all of it. No deduction is applied, because the quantity being measured is the extra tax the job causes.

The childcare bill is the weekly cost for one child, multiplied by the number of weeks paid for, multiplied by the children in care with the sibling discount applied to each child after the first.

The costs of going to work are the monthly figure taken twelve times.

The relief is added back. Under the credit route it is a percentage of the capped expenses, and the percentage is read at HOUSEHOLD income, so it falls as the first salary and the second are added together. Under the workplace account route it is the sheltered amount multiplied by the federal, state and payroll rates together.

What is left is the salary less the taxes, less the childcare after relief, less the work costs. Divided by the salary it is the share kept; divided by a full-time working year of hours it is what the job pays an hour after everything.

Two break-even figures come from the same relationship read backwards: the salary at which what is left is exactly nothing with the childcare held where it is, and the weekly childcare cost at which what is left is exactly nothing with the salary held where it is.

Calculation sequence

This is the order in which the reported figures depend on one another. It is not a claim about the order in which the model evaluates itself.

  1. Work out the childcare bill for the year from the weekly cost, the weeks, the children and the sibling discount.
  2. Add the two salaries to get the household income the relief is read at, and work out what the chosen relief is worth.
  3. Charge the second income its own federal, state and payroll tax.
  4. Take the taxes, the childcare after relief and the work costs off the second income to get what it leaves for the year, and divide by twelve for the monthly figure.
  5. Divide what is left by the salary for the share kept, and by a full-time year of hours for the hourly figure.
  6. Solve the same relationship for the salary that leaves exactly nothing, and again for the weekly childcare cost that leaves exactly nothing.
  7. Over the horizon entered, value the raises the salary earns and what the retirement contributions and the employer match would grow to, and report both separately.
  8. Rerun the whole calculation across a grid of salaries and childcare costs, so the sensitivity to each is visible rather than asserted.

Outputs and interpretation

Output Role Unit What it means
Net Annual Gain primary $/year What the second income leaves for the year once it has paid its own taxes, the childcare it makes necessary and the costs of going to work, and once the relief has been added back. A negative figure is a real answer rather than a fault.
Breakeven Salary primary $/year The salary at which what is kept exactly covers the childcare and the work costs. Below it the job costs money. It charges the full payroll rate on the whole salary, so above the Social Security wage base it is slightly high, and the status line says so when that applies.
Kept Share primary % How much of every dollar of this salary survives to the end. It is the most comparable figure here across different salaries, and it reads nothing when there is no salary to take a share of.
Net Monthly Gain detail $/month The same answer divided by twelve, which is the form most household budgets are kept in.
Hourly Net detail $ What the year leaves divided by a full-time working year of hours. It is the figure that makes a second income comparable with an hourly rate, and it is usually a good deal lower than the one on the payslip.
Annual Childcare detail $/year The whole childcare bill for the year, every child, after any sibling discount and before any relief.
Relief Value detail $/year What the route you chose is worth in money this year. It is added back to what the salary leaves, so it moves both break-even figures directly.
Credit Rate detail % The percentage the dependent care credit is actually paid at for this household income. It reads nothing unless the credit is the route chosen.
Taxes On Second Income detail $/year Every tax this income alone attracts. It is not the household's whole tax bill, and it is not reduced by any deduction.
Work Costs Annual detail $/year The monthly cost of going to work, taken twelve times.
Breakeven Childcare Weekly detail $ The weekly cost of care at which this salary would leave exactly nothing. Above it the job costs money. It is worked out with the relief as it stands now, so at a very different childcare cost the relief itself would change a little and the true crossing moves with it.
Raises Forgone detail $ How much more the salary earns over the horizon because it rises each year, compared with the same salary held flat. It is the raises alone, and it is not the lifetime cost of leaving work.
Retirement Value detail $ What the retirement contributions and the employer match this job funds would be worth at your horizon. It is reported separately on purpose: it is money put away rather than money spent, so it is never netted against what the salary leaves.

Model Status reads OK, or explains why the inputs are not valid or why the answer deserves a second look before you act on it. It is shown alongside the results rather than in place of them.

The calculator also returns a grid that reruns the whole calculation across a range of salaries and childcare costs at once. Its axes, corner and body arrive as separate values and are the grid's parts rather than results to read on their own; the page assembles them into the table.

Every figure above is returned by the model. The page arranges and formats them; it computes none of them.

Validation and status logic

These are the states the delivery's own recorded runs exercise, so the table records what this calculator has been observed to return rather than every branch it could take.

Condition Returned status
A child is in care but no number of weeks has been entered NOT VALID: with a child in care, enter the number of weeks a year the care is paid for
No relief route has been chosen NOT VALID: choose from the list how the childcare is relieved, or choose None if it is not relieved at all
An amount has been entered as a negative number NOT VALID: the two incomes, the weekly childcare cost and the monthly work costs all have to be zero or more
The second income leaves less than nothing for the year CHECK: after the taxes this income attracts, the childcare it makes necessary and the work costs it adds, it leaves less than nothing; the two break-even figures show what would have to change
The second income runs past the Social Security wage base CHECK: this income is above the Social Security wage base, so its last dollars pay no Social Security tax; the break-even salary still charges the full payroll rate and is therefore a little high
None of the preceding conditions applies OK

Assumptions and limitations

  • One federal rate on the whole second income. A salary that straddles two brackets is charged at the rate you enter throughout, which is the right question for a job you are deciding whether to take and the wrong one for a return.
  • The childcare bill is held flat while the salary is swept. A household that would buy different care at a much higher salary is not modelled.
  • The credit percentage is read at household income, and the capped expenses it is worked out on are a published limit that does not rise with the bill.
  • The state figure is one flat rate on the second income. No state's actual rules are modelled, and several states have their own childcare relief that is not counted.
  • The break-even salary charges the full payroll rate throughout, so above the Social Security wage base it is a little high.
  • The raises and the retirement money are reported beside the year's answer and never inside it, because they are not spent.

Restrictions and non-computing states

This calculator enforces the numeric limits recorded above before any figure is worked out, so a value outside them is refused rather than answered.

Two refusals are about combinations rather than single values: care for a child with no weeks of care entered describes no bill, and a relief route has to be chosen rather than left empty, with None available for a household that has neither.

Errors and warnings

NOT VALID means the inputs do not describe a question this calculator can answer, and the figures beside it should not be relied on. CHECK is not an error: the arithmetic is sound and the figures stand, but something about the combination is worth knowing first, most often that the job leaves less than nothing this year. The status is shown with the results rather than in place of them, so a flagged answer is still a readable one.

A value the page itself refuses, because it falls outside the limits above, is rejected before the calculation is requested and no figures are returned at all. That is different again from a transport or service failure, where the page reports that the result could not be fetched rather than showing a stale or partial one.

References

The relief that gets added back is the child and dependent care credit, and the Internal Revenue Service describes it as "a percentage of the amount of work-related expenses you paid to a care provider for the care of a qualifying individual", where "The percentage depends on your adjusted gross income." That is why this calculator asks for both salaries rather than only the one being weighed up. The same page sets the ceiling on the expenses the credit may be worked out on: "The total expenses that you may use to calculate the credit may not be more than $3,000 (for one qualifying individual) or $6,000 (for two or more qualifying individuals)." A bill far above that ceiling is relieved no further. See Topic no. 602, Child and dependent care credit.

The payroll tax charged on the second income is the one part of its tax bill that does not depend on the household's bracket. The Service gives the employee shares as "6.2% for the employee" for Social Security and "1.45% for the employee" for Medicare, notes that "There's no wage base limit for Medicare tax", and publishes the Social Security wage base for the year. That wage base is the reason a very high second salary changes the answer in a way the break-even figure does not follow. See Topic no. 751, Social Security and Medicare withholding rates.

The credit percentages themselves move with the law and are not quoted here, because a figure copied from one year's table is the commonest way a page like this goes quietly out of date. Check the schedule for the year you are asking about, and check what your own provider charges rather than any average.

These sources provide background; they do not supply the calculator's assumptions or certify its result. This calculator is informational and is not financial, investment, or tax advice. Results follow directly from the salaries, the childcare and the costs you enter, and this page measures the extra tax a second income causes rather than a household's whole tax bill.

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