Financial calculators that get the math right.

Every calculation shows its work. Every assumption is stated and overridable. Built by data people who run these numbers for our own decisions.

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Mortgage & Home

Mortgage Payment Calculator

Monthly payment with P&I, taxes, insurance, and PMI breakdown.

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Home Affordability Calculator

How much house you can afford based on income and debts.

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Investing

Compound Interest Calculator

See how contributions and compound growth build wealth over time.

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Tax & Income

Tax Bracket Calculator

Federal tax by bracket with effective and marginal rates.

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Paycheck Calculator

Take-home pay after federal, state, FICA, and deductions.

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Why PennyCalc?

Visible math

Full amortization schedules, bracket breakdowns, and year-by-year projections. Nothing hidden behind a paywall.

Override everything

Every assumption is stated and adjustable. Change the tax rate, insurance, PMI threshold — your scenario, your numbers.

Instant results

All math runs in your browser. No server calls, no loading spinners, no email required. Adjust a slider and see the impact immediately.

PennyCalc provides financial calculators for educational purposes. Results are estimates based on the inputs you provide. Consult a financial professional for advice specific to your situation.