Personal Finance

Estimates the annual and monthly income a lump sum buys over a fixed term at an assumed interest rate, with payments at the start or the end of each year and an optional annual escalation. It reports the income, the total paid over the term, and the years of payments needed to return the premium. It prices a term certain, so it carries no mortality pooling and no insurer expense loading, and a real quote will be lower.

Works out what to trade to bring a portfolio back to its target weights, and answers the two questions most rebalancers skip: whether the drift is far enough past your tolerance band to be worth trading on at all, and how much of the job a contribution directed at the underweight holdings can do without selling anything. Use it before placing trades, to see what a sale would cost you and whether new money can spare you one.

Itemises what you will be asked to pay at closing, separated into lender fees, third-party fees and prepaid items, and adds the down payment to give the cash you actually need. The split is the point: only lender fees move much when you change lender, and prepaid tax and insurance are money you owed anyway rather than a cost of borrowing.

Projects a balance forward at a rate you quote, adding the interest as often as the account really adds it, from once a year to continuously, and reports the effective annual rate that frequency actually pays. It also compares the answer against the same money at simple interest, so the part of the balance that is compounding rather than deposits is a figure rather than a feeling, and puts the whole projection on a grid of rates and horizons.

Compares investing a sum all at once against feeding it in over several months, on a return you supply, and reports what each is worth at the end, how much the waiting costs and what it saves if the market falls instead. It also runs the comparison across a band of returns you are unsure about and reports how often each way comes out ahead.

Computes the invested balance that supports your spending at the withdrawal rate you plan to use, then finds how many years of saving and real growth it takes to reach it. It reports your savings rate, your age on arrival, and how much sooner you would arrive saving half as much again. Growth is a single average real return, so it says nothing about the order in which returns arrive.

Reports equity, the first-mortgage loan-to-value ratio and the combined ratio across every lien, and how much more you could borrow before reaching the limit a lender applies. It reports both mortgage-insurance thresholds and which value each rule is measured against, because automatic termination uses the original price while cancellation on today's value has to be requested.

Prices an investment fee as what it costs rather than as what it is billed: the same plan is run twice, once with no fee and once with the fees you pay, and the gap between the two balances is split into the fees charged and the growth those fees never made. A one percent annual charge over thirty years costs about two and a half times the fees actually taken and a quarter of the final pot, and it also prices a second fee against yours so an active fund and a tracker can be compared in one place.

Works out the most you can pay for a home from your income, your existing debts and the two qualifying ratios a lender applies, and says which of the two binds. Because property tax scales with the price the model is solving for, the affordable price is solved as a fixed point rather than divided out, which is the step that makes the answer consistent with the payment it implies.

Works out the full monthly cost of a mortgage -- principal, interest, property tax, homeowner insurance, association dues and mortgage insurance -- and, unlike most calculators, stops charging the mortgage insurance at the month the loan reaches 78 percent of the original price, where it terminates. It reports that month, the total insurance actually paid, and what the payment drops to afterwards.

Prices discount points as an investment with a horizon: what they cost, what they save each month, when the saving has repaid them, and what they are worth over the time you expect to keep the loan. It counts the extra principal the lower rate pays down by then, which other calculators omit and which is worth four figures on an ordinary loan, and can restate the whole trade as a present value.

Compares a shorter mortgage with a longer one on the same amount: the payment and total interest of each, and then the comparison most tools omit -- on the day the shorter loan is paid off, what is still owed on the longer one against what the payment difference would have grown into if invested. It also says when the longer loan would be gone if you simply paid the shorter loan's payment on it.

Values a pension offered as a monthly payment against a lump sum alternative by discounting the payments at the return you believe you could earn on the cash, including any annual increase and a survivor benefit. It reports which is worth more today and the discount rate at which the two are equal, and it says so plainly when the pension is worth less than the lump sum at every non-negative return, because then no such rate exists.

Turns a nominal return into what it is actually worth once inflation and, optionally, tax have taken their share, using the Fisher relation rather than the usual shortcut of subtracting inflation from the return. It reports the exact real return beside the shortcut and the gap between them, the return needed merely to keep pace after tax, what a starting amount becomes on a statement against what it will buy, and a weighted grid of both rates that says how often the money gains purchasing power at all.

Says how many months a refinance takes to repay what it costs, measured against the term remaining on the loan you have rather than a fresh full term, so a longer new loan cannot disguise re-extension as a saving. It reports the years added to the term as its own figure, compares total remaining cost under each loan, and handles costs rolled into the balance, where there is no break-even month at all.

Compares renting with buying on the net worth each leaves you with at the end of the period you expect to stay, rather than on monthly cost. The renter's down payment and every month of saved cost are invested at a return you set, the owner's spare cash is invested in any month rent costs more, and the sale at the end pays selling costs and repays the loan. It also reports the month from which buying goes ahead and stays ahead.

Projects the required minimum distributions from a retirement account year by year from a life-expectancy divisor that falls as you age, and reports the largest single year, the total distributed and the balance left at the end. Enter a tax rate and it also reports the tax on the distributions. The divisors are illustrative inputs you take from the governing table yourself; none is reproduced here.

Works out what you and your employer put into a workplace retirement plan over a year from the share of pay you defer, applies the plan's tiered match, and reports any employer money you are forfeiting. Use it to find the deferral that captures the whole match. The deferral and catch-up limits are illustrative inputs you set yourself, not a reproduced schedule.

Runs a retirement balance forward year by year against a withdrawal that rises with inflation, and reports whether the money lasts, the year it would first fall short, and the withdrawal that would last exactly the planned period. Use it to test a four percent rule or any other starting withdrawal against your own return and inflation assumptions.

Projects what your retirement savings grow to by the age you plan to stop working, reported in today's money as well as the money of that year, and the annual income the balance supports at your chosen withdrawal rate. Enter a target income and it also reports the shortfall and the extra annual saving that would close it.

Compares converting a traditional balance to a Roth against leaving it alone, paying the conversion tax now and taxing the untouched balance when you eventually draw it. It reports which comes out ahead, the outside cash the conversion needs, and the future tax rate at which the two are equal. It models one conversion in isolation, not the bracket, surcharge and credit effects of adding the converted amount to a year's income.

Puts the rule of 72 beside the exact doubling time for your rate and compounding frequency, and reports how far the rule is off in years and as a share, the numerator that would be exact at your rate, and the range of rates over which the rule stays within a quarter of a year. It also gives the exact time to triple and to grow tenfold, and tabulates the error across a grid of rates and numerators so the safe region can be seen rather than assumed.

Works out what you must put aside each month to reach a savings goal by a deadline, given what you have already saved and the return you expect. It then does the two things a single division cannot: it restates the goal at the deadline when the thing you are saving for gets more expensive, and it runs the whole plan again across a spread of returns, so the answer arrives as a chance of getting there and a range of outcomes rather than as one confident number.

Applies the early-claiming reduction and the delayed-retirement credits to the monthly benefit you would receive at full retirement age, then compares two claiming ages on the total received by a planning age and on the age at which the later claim overtakes the earlier one. The adjustment is derived from the published monthly rates rather than read from a table, and the benefit amount is yours to supply from your own statement.

Compares a traditional and a Roth contribution of the same size by growing each forward and taxing it on the rules that apply to it, so the two are judged on what you keep rather than on what goes in. It reports which comes out ahead and the future tax rate at which they are equal, and it can invest the traditional contribution's up-front tax saving in a taxable side account, which is the comparison most calculators leave out.