Money calculators that show you the numbers — instantly
Updated July 2026
Plan investments, crush debt, and pay off your mortgage faster. Every PennyPath calculator runs entirely in your browser — your inputs never leave your device.
- No account needed
- Nothing uploaded
- Free forever
- Works offline
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The essential tools for everyday money decisions — each with clear results, charts and a plain-English explanation.
Compound Interest
See how savings and investments grow over time with regular contributions.
BorrowLoan & Amortization
Monthly payment, total interest and a full amortization schedule for any loan.
HomeMortgage Payoff
How much time and interest you save by adding extra to each payment.
DebtSnowball vs Avalanche
Compare two payoff strategies across all your debts and pick the winner.
SaveSavings Goal
Find the monthly amount needed to hit a target by a chosen date.
RetireFIRE Number
Your financial-independence target and how many years until you reach it.
DecideRent vs Buy
Compare the true cost of renting versus buying over your time horizon.
EarnSalary ↔ Hourly
Convert between salary, hourly, weekly and monthly pay in seconds.
Why people trust PennyPath
Truly private
Every calculation happens in your browser with JavaScript. We never receive, store, or upload your figures. Close the tab and it's gone.
Fast & free
No account, no paywall, no “export blocked.” Pages are lightweight static files that load instantly and even work offline.
Transparent math
We publish every formula on our methodology page so you can verify the numbers yourself. No black boxes.
Learn the “why” behind the numbers
How compound interest really works
The eighth wonder of the world, explained with simple examples.
GuideDebt snowball vs avalanche
Which payoff method saves more money — and which keeps you motivated.
GuideWhat is the FIRE movement?
Financial Independence, Retire Early — and the 25× rule that powers it.