Financial calculators that actually show you the math
Interactive, beautifully charted, and completely private — every number is computed in your browser and never sent anywhere. No sign-up, no paywall, no dark patterns.
Mortgage Calculator
Estimate your monthly mortgage payment, see how principal and interest shift over time, and find out how much extra payments save you — all computed in your browser.
Loan Calculator
Calculate the monthly payment and total interest on an auto or personal loan, and compare how different terms change the cost.
Retirement Calculator
Project how your savings could grow with compound returns and regular contributions — including an uncertainty range, not just a single optimistic line.
Income Tax Calculator
Estimate your federal income tax by bracket and see why your effective rate is lower than your top marginal rate.
Why FinCalc
Most calculators give you a single number and an ugly table. FinCalc shows you how principal and interest shift over time, how extra payments change your payoff date, and how a range of returns could play out — with charts you can actually explore on any device.
Private by design
There are no accounts and no servers crunching your finances. Everything runs locally, so your numbers stay on your device. That is a privacy promise and a compliance safeguard in one. For general information only — not financial, investment, or tax advice.