About and how we calculate

Methodology

Every calculator on this site uses standard, public financial mathematics: the amortization formula for loans and mortgages, compound growth formulas for investing and retirement, the 28/36 lender guideline for affordability, and statutory-style period conversions for pay. Each calculator page shows its formula and a worked example in plain words, so any result can be checked by hand.

Before a calculator is published, its output is tested against known worked examples. A $100,000 loan at 6% over ten years must return a payment of $1,110.21 and total interest of $33,224.60; a salary of $50 an hour at 40 hours a week must read $104,000 a year before paid time off. If a test fails, the calculator does not ship.

All maths runs in your browser. Nothing you type is sent to a server, stored, or shared, and there is no account to create. Results are estimates: lenders, tax authorities and markets use their own rounding, fees and rules, and nothing here is financial, tax, legal or mortgage advice.

CalcLedger is a working name for a site in active development. New calculators are added in a published priority order, starting with the ones people use daily.