Calculator overview
Inputs and outputs
This summary comes from the calculator's published input and output contract.
Inputs
- Sibling Discount
-
When omitted Blank
Unit fraction Default Not set Range 0 to 0.3
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.
- Second Income (required)
-
Unit $/year Default 60760 Range 0 to 2000000
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.
- Salary Growth
-
When omitted Blank
Unit fraction Default Not set Range 0 to 0.08
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.
- State Rate
-
When omitted Blank
Unit fraction Default Not set Range 0 to 0.133
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.
- Years
-
When omitted Blank
Unit years Default Not set Range 1 to 18
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.
- Work Costs Monthly
-
When omitted Blank
Unit $/month Default Not set Range 0 to 1000
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.
- Weeks Of Care (required)
-
Unit weeks Default 50 Range 0 to 52
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.
- Retirement Pct
-
When omitted Blank
Unit fraction Default Not set Range 0 to 0.25
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.
- Employer Match Pct
-
When omitted Blank
Unit fraction Default Not set Range 0 to 0.1
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.
- Children In Care (required)
-
Unit count Default 1 Range 0 to 6
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.
- Childcare Weekly (required)
-
Unit $ Default 332 Range 0 to 2000
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.
- First Income (required)
-
Unit $/year Default 72380 Range 0 to 2000000
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.
- Relief Type (required)
-
Default Dependent care credit Allowed Dependent care credit, Dependent care FSA, None
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.
- Marginal Rate (required)
-
Unit fraction Default 0.22 Range 0 to 0.37
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.
- Investment Return
-
When omitted Blank
Unit fraction Default Not set Range 0 to 0.12
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.
Outputs
- Table1 Gain Column Input
-
Unit currency
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.
- Table1 Gain Corner
-
Unit currency/yr
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.
- Table1 Gain Column Axis
-
No unit declared
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.
- Relief Value
-
Unit $/year
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.
- Retirement Value
-
Unit $
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.
- Taxes On Second Income
-
Unit $/year
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.
- Work Costs Annual
-
Unit $/year
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.
- Table1 Gain Values
-
Unit currency/yr
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.
- Table1 Gain Row Axis
-
No unit declared
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.
- Table1 Gain Row Input
-
Unit currency/yr
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.
- Credit Rate
-
Unit fraction
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.
- Hourly Net
-
Unit $
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.
- Breakeven Salary
-
Unit $/year
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.
- Annual Childcare
-
Unit $/year
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.
- Breakeven Childcare Weekly
-
Unit $
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.
- Net Monthly Gain
-
Unit $/month
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.
- Raises Forgone
-
Unit $
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.
- Net Annual Gain
-
Unit $/year
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.
- Kept Share
-
Unit fraction
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.
- Model Status
-
No unit declared
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.
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.
- Work out the childcare bill for the year from the weekly cost, the weeks, the children and the sibling discount.
- Add the two salaries to get the household income the relief is read at, and work out what the chosen relief is worth.
- Charge the second income its own federal, state and payroll tax.
- 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.
- Divide what is left by the salary for the share kept, and by a full-time year of hours for the hourly figure.
- Solve the same relationship for the salary that leaves exactly nothing, and again for the weekly childcare cost that leaves exactly nothing.
- 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.
- 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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