Age Calculator
Enter a birth date to get an exact, calendar-aware age — not a rough days-divided-by-365 guess — plus how long until the next birthday.
That date is in the future — enter a birth date that's today or earlier.
Real calendar math, not an average
This calculator subtracts your birth date from today one calendar unit at a time — years first, then months, then days — borrowing a month's worth of days or a year's worth of months whenever a unit goes negative, exactly the way you'd count by hand. That's different from (and more accurate than) taking the total number of days you've been alive and dividing by 365, which drifts wrong across leap years and unevenly-sized months. Total days lived is provided separately as its own exact figure, using a UTC-anchored day count so it's never thrown off by daylight saving time.
Worked example
Someone born March 15, 1990, checking on August 14, 2026: that birthday already happened this year, so their age is 36 years, 4 months, 30 days — and since this year's birthday has passed, the next one lands on March 15, 2027, which is 213 days away.
Frequently asked questions
How is this different from just dividing total days by 365?
Dividing by 365 quietly gets it wrong for a large share of dates, because it ignores leap years and the fact that months aren't all the same length. This calculator instead subtracts calendar units directly — years, then months, then days — borrowing from the previous unit exactly the way you would counting on your fingers from one birthday to today. The result is the exact age a calendar would show, not a statistical approximation.
What happens with a February 29 birthday in a non-leap year?
We treat February 28 as that year's birthday for the "next birthday" calculation, since March 1 in a non-leap year is one day too many after February 28 to feel like a one-year anniversary. This is a genuine judgment call — reasonable people pick March 1 instead — but we're explicit about it rather than letting the date silently become invalid, and it only ever affects the countdown figure, never the exact years/months/days age itself.
Why does it need my exact birth date instead of just a year?
Because the day and month are exactly what make an age calculation precise instead of a rough estimate. Two people born in the same year can differ by a full year of age today depending on whether their birthday has happened yet — the month and day are what tell this calculator (and everyone else) which side of that line you're on.
Is my birth date sent anywhere?
No. The date you enter never leaves your browser — every calculation here runs locally in JavaScript, with nothing sent to, stored by, or logged on a server. That's true for every tool on this site.