Finance calculators that show their math

Free, fast, no signup. Every calculator explains its formula in plain English, cites an authoritative source, and is built US-first - real tax rules, real dollar defaults.

Debt

Debt Snowball vs Avalanche CalculatorCompare both payoff methods side by side - see your debt-free date, total interest, and which method wins for your exact debts.

Savings

HYSA vs CD vs Treasury Bill CalculatorAfter-tax 3-way comparison that models the state-tax exemption on Treasury interest.

Taxes

1099 Quarterly Tax CalculatorSimple quarterly estimated tax amounts for freelancers, with the safe-harbor rule built in.

Coming soon

Mortgage Extra Payment Calculator
Emergency Fund Calculator
401(k) Employer Match Maximizer
Compound Interest Calculator
Car Loan Calculator
Credit Card Minimum Payment Calculator
Hourly to Salary Calculator
Tip Pooling Calculator