Personal Finance Calculators

Your savings rate combined with time is the single number that determines when you reach financial independence. This calculator projects when your portfolio will cross 25× your annual spending — your FI target — and shows how much sooner you'd get there if you cut monthly spending. Money you stop spending is money you start investing, so a small cut moves the target closer and increases what you contribute toward it. Enter household income before taxes — the gross number on your offer letter or W-2. The calculator estimates federal, FICA, and state taxes behind the scenes and shows you what's left as take-home.

The standard script — forty years of work, then leisure — bets the meaningful experiences happen at the end. A sabbatical inverts that: take a stretch off now, while you have your health, and pay for it with a slightly later FI date. The sabbatical months contribute nothing to savings and withdraw the listed net cost from your portfolio; afterward you return to your current income. The chart's shaded band is the time off.

A $15 charge feels harmless, but the real price isn't what you pay — it's the wealth those dollars would have built if invested instead. Foregone growth assumes each monthly payment is invested at your expected real (inflation-adjusted) return, compounded monthly. The amount due is the future value of all those payments: the portfolio you'd have had if you'd never subscribed. Edit the list to match your own.

Fund fees are charged on your entire balance every year, so as your portfolio grows, the dollars the fund skims grow with it. Net return = gross return minus the expense ratio, applied annually. Both funds here have identical gross performance and the same contributions and starting balance — the only difference is what the manager keeps. Figures are in today's (real) dollars.

Net worth = investments minus remaining debt at each year-end. The investment return is your shared real-return slider plus 3% inflation, so it's nominal — apples-to-apples with the quoted debt APR. Debt first throws the minimum plus all extra cash at the debt until it's gone, then redirects the whole payment into investments. Invest first pays only the minimum and invests everything else from day one. Monthly compounding throughout. The two totals usually land within a fraction of a percent of each other, so the chart plots the difference between them instead of the totals — that's the number that answers the question.

A refinance is a one-time fee bought in exchange for a lower monthly payment, and the whole question is whether the savings catch up to the fee before you sell, pay off the loan, or refinance again. This runs the actual amortization on both loans and tracks each one's cumulative cost — closing costs paid, every monthly payment, plus whatever you'd still owe if you sold that year. The chart's crossing point is where the refi turns from a net loss into a net gain. A rate gap that looks like a deal often isn't once the closing costs are taken seriously.

Owning is a great deal for some people and a wealth trap for others, and the deciding factor is almost never the listing price. It's how long you stay, what a parallel investment of the down payment would have done, and whether rent on the same home sits meaningfully below the full cost of owning it — mortgage, property tax, maintenance, insurance. Both paths are simulated month by month: the buyer sells at the horizon (less 6% selling costs), the renter invests the upfront cash plus whatever owning would have cost extra each month. When owning is the cheaper month, the buyer invests the difference instead.

The honest answer for most households is yes — and by a wider margin than the USDA's scary headline suggests. The big fixed costs of your life — housing, utilities, one of your cars — don't scale per kid; food, clothes, and activities do, but modestly, and the expensive stretch is concentrated in the daycare years. This adds up the marginal cost of one more child across 18 years and compares your FI trajectory with and without them, under the same income. The chart's shaded band is the daycare phase — where nearly all the damage happens.

The salary your partner walks away from is not the cost of staying home. Taxes you no longer owe come back, childcare you no longer pay for comes back, and the commute, parking, work lunches, and dry cleaning come back too. The honest cost of going to one income is whatever's left after those offsets — usually a fraction of the gross. This does that subtraction and projects both the two-income and one-income FI dates side by side. Income is taxed as a household (married filing jointly), so dropping a salary lowers the tax bill on what's left.

An emergency fund is insurance against the version of your life where the paycheck stops. The right size isn't a rule of thumb — it's a function of how stable your income is, how many people depend on it, and whether a second earner is backing you up. The recommended cushion starts from your job stability, adds a month and a half if you're the only earner, and half a month per dependent. Multiply that by your essential monthly expenses and you have a target tuned to your situation, not a generic three-to-six.