About AgeMath
AgeMath is the date arithmetic: exact age to the day, the countdown to the next birthday, days lived, and any two dates compared.
AgeMath exists because "how old exactly" and "how many days until" are asked constantly and answered imprecisely. Date arithmetic is exact math — and one page makes it instant.
Every calculator on AgeMath shows its formula and its assumptions on the page, so you can check the math, reproduce it in a spreadsheet, or argue with it. Inputs are processed entirely in your browser — nothing is sent to a server, and there are no accounts.
AgeMath is an independent, ad-supported project. We are not affiliated with any lender, brand, agency, or the sources we cite (published industry standards). If a number looks wrong, the contact page reaches a human who fixes it.
What makes AgeMath different
- Your numbers never leave your browser. Every calculator on AgeMath runs entirely on your device. We never see, store, or transmit the figures you enter — there are no accounts and no server-side processing of your inputs.
- Published methodology. Each calculator page explains the exact formula it uses and the assumptions behind it, so you can check our work or reproduce it in a spreadsheet.
- Free, forever, without a paywall. AgeMath is supported by advertising. There is no premium tier, no email gate, and no upsell.
Independence
AgeMath is an independent educational project. We are not affiliated with, endorsed by, or acting on behalf of any government agency, lender, insurer, or the organizations whose formulas and public data we reference (such as published industry standards). All trademarks and referenced standards belong to their respective owners.
Questions, corrections, or suggestions are genuinely welcome — get in touch.