Free money calculators that actually show their work

Pick a calculator below. Every one of them is free, runs right in your browser, and shows you the plain-English math behind the number: not just a black box.

No signup required Works on your phone 2026 tax numbers

Home & big purchases

HM Mortgage Payment CalculatorPrice, down payment, rate, term, taxes, insurance, PMI, HOA → LN Loan Payment CalculatorAny fixed-rate loan: payment, interest, amortization table → CAR Car Loan CalculatorPrice, down payment, trade-in, sales tax, APR, term →

Debt & payoff

CC Credit Card Payoff CalculatorMinimum payment trap vs. paying more: months and interest →

Saving & investing

SV Savings Plan CalculatorTurn any goal into a weekly or monthly number, plus a printable tracker → CI Compound Interest CalculatorHow much to save monthly to hit a target by a certain age → 401K 401(k) Growth CalculatorContribution %, employer match, raises, returns, and the +1% effect →

Paycheck & taxes

PC Paycheck Take-Home Calculator (2026)Salary to real take-home: federal tax, FICA, 401(k), state tax →

Get new calculators when they drop

Marcus adds a new calculator most weeks. No spam, just the link when it's live.