Personal Finance Calculators
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When can I retire?
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. Income is entered pre-tax; the calculator estimates federal, FICA, and state taxes behind the scenes to derive your annual savings.
Real (inflation-adjusted) returns. Tax estimate assumes married filing jointly, 2024 federal brackets with the standard deduction, 7.65% FICA, and a 5% state placeholder. Annual savings equals estimated take-home minus annual spending. Social Security is intentionally excluded here — it's modeled separately in the Social Security calculator below.
Should I move cities?
Where you live is the largest line item in most household budgets — housing, taxes, daily costs, even the price of a gallon of milk vary wildly by metro. A move can either accelerate your path to FI by lowering spending and increasing what you save, or push it back if you're trading up to somewhere with a higher cost of living. Pick your current city and explore real US metros — each dot's position shows the FI impact of relocating there. Income is held constant; the moving cost comes out of your starting portfolio.
City decision space
Each dot is a real US city with plausible cost-of-living adjustments to your spending. Click a city to make it your desired destination.
Cost-of-living indices are rough metro-area averages (national average = 100). Equivalent spending in a new city = your current spending × (new city index / current city index). Income is assumed to stay constant (e.g., remote work). The moving cost is subtracted from your starting portfolio in the move scenario.
Should I take a Sabbatical?
The standard retirement script — forty years of work, then twenty-five of leisure — assumes the meaningful experiences happen at the end. A sabbatical inverts that bet: take a stretch off now, while you have your health and your kids are young, and pay for it with a slightly later FI date. This calculator measures the trade for any length from one month up to two years. How many extra months of work does a real sabbatical actually cost? Often less than people fear.
The sabbatical year contributes nothing to savings and withdraws the listed cost from your portfolio. The cost should reflect actual spending during the year off (rent, food, travel) net of any income. Assumes a return to current household income afterward.
What do my subscriptions really cost?
A $15 streaming charge feels harmless on its own, but every monthly subscription is a small hole in the bottom of your savings bucket. The real price is not what you pay — it's the wealth those dollars would have built if invested instead. This calculator adds up your subscriptions and shows the true lifetime cost: what you'll pay plus the growth you'll forgo by spending instead of investing. Edit the list to match your own.
Foregone growth assumes each monthly payment is invested instead at the expected real (inflation-adjusted) return, compounded monthly. True cost is the future value of those payments — the portfolio you would have had if you'd never subscribed. Subscription prices are real-dollar amounts; price hikes that track inflation are already reflected.
How much do fees eat from my returns?
A 1% expense ratio sounds like a rounding error — until you watch it run for thirty years. Fund fees are charged on your entire balance every year, so as your portfolio grows, the dollar amount the fund skims off grows with it. The same percentage that takes $100 in year one quietly takes thousands per year by retirement. This calculator compares two funds with identical performance and only one difference: their expense ratio. The gap is what the higher-fee fund is silently taking out of your future.
Expected gross return is the market return before fees. Net return = gross return minus expense ratio, applied annually to the entire balance. Both scenarios receive the same monthly contribution and start with the same portfolio. Real (inflation-adjusted) figures — this is the dollar gap in today's purchasing power, not nominal dollars.
How much should I save per kid for college?
A 529 plan is a compound-interest engine wearing a tuition costume. The dollar you contribute when your child is two has sixteen years to grow before the first tuition bill arrives; the same dollar contributed when they're twelve has only six. Pick the kind of school you're planning for, list each kid's current age, and choose how much of the bill you intend to cover. The calculator uses today's published cost figures, an accurate college-inflation assumption, and an age-based 529 glide-path return — then tells you what to save monthly (or as a single lump sum) to fully fund the plan.
Assumptions baked in: college costs grow at 5% nominal / ~2% real above general inflation per recent College Board data; the 529 follows a typical age-based glide path averaging ~5% real return (heavier equities when kids are young, shifting to bonds and cash as college approaches). Numbers shown are in today's dollars. Withdrawals from 529 plans for qualified expenses are federal-tax-free.
Debt or invest?
You've got extra cash each month — does it work harder paying down a balance or buying index funds? The honest answer is just arithmetic. Money you don't owe to a lender stops earning the lender its interest; money you invest earns the market's. Whichever rate is larger usually wins. This calculator simulates both paths month by month — extra cash routed at the debt until it's gone, versus minimum payments plus everything else invested — and reports the gap in plain net worth at the end of your horizon.
Net worth = investments minus remaining debt, evaluated at each year-end. The investment return is the shared real-return slider plus a 3% inflation assumption to keep it nominal — apples-to-apples with the quoted debt APR. "Debt first" sends the minimum plus all extra cash at the debt until it's gone, then redirects the whole payment stream into investments. "Invest first" pays only the minimum and invests everything else from day one. Monthly compounding throughout.
Should I refinance my mortgage?
A refinance is a one-time fee bought in exchange for a lower monthly payment. The whole question is whether the monthly savings catch up to the closing costs before you sell the house, pay it off, or refinance again. This calculator runs the actual amortization on both loans, finds the month you break even, and shows the cumulative cost gap over however long you plan to stay. The interest-rate gap that looks like a deal often isn't, once the closing costs are taken seriously.
Cumulative cost = closing costs paid + all monthly payments + remaining loan balance at the end of each year (the principal you'd owe if you sold). The crossover point is where refinancing turns from a net loss into a net gain. Break-even is the simple "closing costs ÷ monthly savings" measure — the accounting break-even is slightly later because the new loan amortizes more slowly at first. Tax effects (mortgage interest deduction) are not modeled; for most filers since 2018 the standard deduction makes this a wash.
Should I buy a house or rent and invest?
Owning a home is a great deal for some people and a wealth trap for others — the deciding factor is almost never the listing price. It's how long you'll stay, how a parallel investment of the down payment would have done, and whether the price you'd pay to rent the same home is meaningfully below the full cost of owning it (mortgage, property tax, maintenance, insurance — the parts realtors don't mention). This calculator simulates both paths month by month and tells you which one builds more net worth, and at which year the tradeoff actually flips.
All numbers are in today's dollars (real returns, real appreciation, real rent inflation assumed to be zero on top of general inflation). The buy scenario sells at the horizon and pays 6% selling costs to find net equity. The rent scenario invests the upfront cash (down payment + 3% closing costs) plus any month-by-month savings (rent < own-cost) into a market portfolio. When ownership is cheaper than rent, the buyer pockets the difference instead. Property tax and maintenance scale with home value as it appreciates. Tax deductions are not modeled.
Can we afford another kid?
The honest answer for most households is yes — and by a wider margin than the USDA's scary headline number suggests. The biggest costs of a child are concentrated in the daycare years, then drop sharply. The big fixed costs of your life — rent or mortgage, utilities, one of your cars, the streaming subscriptions — don't scale per kid. Food, clothes, and activities do scale, but modestly. This calculator adds up the marginal cost of one more child across 18 years, shows when those costs hit, and tells you what it does to your FI date. The cost is real, but it's almost always smaller, more lopsided in time, and more recoverable than people expect.
Costs are in today's dollars. Year-one setup is a one-time hit. The daycare phase models the years infant-care or preschool is needed; pull that slider to zero if you have free family care, or up if you're in a high-cost metro. Ages 6–17 covers everything else that scales per kid — food, clothes, activities, sports, healthcare copays — but not fixed costs like housing or one of your cars, which don't change because there's one more person at the table. The FI chart compares your current family to the same family with one more child under the same income.
Can a parent stay home?
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. Commute, parking, workday lunches, and dry cleaning come back. A second cook in the house tends to cut grocery and convenience spending too. The honest cost of going to one income is whatever's left over after those offsets — usually a fraction of the gross salary number. This calculator does that subtraction and shows what single-income life does to your FI date.
Taxes use the page's MFJ federal-bracket estimator plus FICA and a 5% state placeholder. "Take-home after" is taxes on the remaining one-income household. True annual cost = gross salary − tax savings − childcare savings − work expenses saved − lifestyle reduction. Effective hourly cost divides that by a standard 2,000-hour work year, so you can decide whether your partner's hour of work — net of everything — clears the bar for what you'd trade an hour for. The FI chart projects both scenarios indefinitely at current spending and income, so it's a worst-case: if the at-home parent returns to work later, the real picture is better.
How much should I keep in an emergency fund?
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 essential your monthly expenses are, how stable your income is, how many people depend on it, and whether there's a second earner backing you up. Three months covers a typical professional. Nine months is closer to right for a sole earner with kids and a variable-income job. This calculator sets a target tuned to your situation and tells you how long it'll take to get there at your current pace.
The recommended months of cushion starts at a base set by your job stability (very stable 3, typical W-2 4.5, variable 6, very volatile 9), then adds 1.5 months if you're the only earner in the household and 0.5 months per dependent. Target fund size = recommended months × essential monthly expenses. The chart projects your balance forward at the listed monthly savings rate, with no interest assumed — emergency funds belong in a high-yield savings account, where the real return after inflation is roughly zero.