Age Calculator FAQ
The calendar math behind exact ages. Tap any question to expand.
How is chronological age calculated exactly?
Subtract birth year/month/day from the target date, borrowing days from the previous month's true length when needed. This yields correct years, months and days including leap years — no average-month drift.
What is my age in Y;M;D format for testing?
Use the chronological-age page and set the as-of date to your test date — read years;months;days directly from the hero line. The shareable URL embeds both dates.
Do Feb 29 birthdays count on non-leap years?
Legally it varies by jurisdiction (Feb 28 or Mar 1). We map the next-birthday countdown to Feb 28 in common years. Elapsed-day counts are always exact regardless.
How many heartbeats have I done?
Roughly one beat every 0.857 seconds (70 bpm). Total days × 86,400 ÷ 0.857 gives your lifetime estimate. Real rate varies — treat as a fun stat.
Why does my age in days differ on other sites?
Sites that divide by an average month length (30.44 days) drift by ±2 days. Calendar-exact borrowing never drifts.
Can I share my result?
Yes — after picking dates, hit “Copy share link.” The URL contains ?dob=YYYY-MM-DD&asOf=YYYY-MM-DD and anyone opening it sees the same calculation.
Is my birth date private?
Yes — all math runs in your browser. Nothing is uploaded, stored, or logged.
How is half-birthday calculated?
Add 6 months to your birth date, clamping the day to the target month's length (e.g., Aug 31 → Feb 28/29). We show it under your result.