Age Calculator
Use this free online Age Calculator to work out an exact age in years, months, weeks, days, hours and minutes from any birth date. It is useful for filling out forms with a precise age requirement, planning birthday milestones, calculating an actor's age on a release date, or just satisfying curiosity about how many days you have been alive. Pick a date of birth and an optional 'as of' date — the calculator handles leap years, time zones and month-length differences automatically. It also tells you how many days remain until the next birthday so you can plan ahead. Results appear instantly with no sign-up.
About
This calculator computes the precise age between two dates. By default, the second date is set to today. The result is shown in years/months/days plus total weeks, days, hours, minutes, and seconds.
How to Use This Age Calculator
Calculating an age takes about ten seconds — pick the date of birth and the calculator does the rest.
- Pick the date of birth using the calendar input.
- Optionally change the 'as of' date if you want the age on a specific past or future day; otherwise it defaults to today.
- Click Calculate Age.
- Read the breakdown — full years and months, plus the running totals in weeks, days, hours, minutes and seconds.
- Check the Days Until Next Birthday line to plan a celebration.
Example Calculation
If your date of birth is 15 March 1990 and today's date is 7 May 2026, your age is 36 years, 1 month and 22 days. That's roughly 13,202 days, 316,856 hours, or 19 million minutes alive. Your next birthday (15 March 2027) is 312 days away — handy for planning a celebration.
How This Age Calculator Works
Calendar maths is fiddlier than it looks because months have different lengths and leap years add an extra day every four years (with exceptions). The calculator handles this by converting both dates to the underlying epoch milliseconds, subtracting them, and then walking back into human-friendly units. Years and months are computed by counting whole calendar years between the two dates, then the remaining months and days. The weeks, days, hours, minutes and seconds totals are computed straight from the millisecond difference, so they are precise regardless of which months are involved. Leap-year-aware logic ensures someone born on 29 February gets the right age on a non-leap year. The 'days until next birthday' figure projects the next anniversary in the as-of year and counts the days remaining; if the birthday has already passed this year it projects to next year. All calculations happen in your browser using the same JavaScript Date object that powers most websites, so there is no privacy risk and the result matches what an official form would compute.
Last updated: May 2026.
Frequently Asked Questions
How do you calculate someone's exact age?
Subtract the birth date from the comparison date, then break the difference into years, months, and days while accounting for the different lengths of each month and for leap years.
Does this calculator account for leap years?
Yes. Each calendar month uses its actual length, and February 29 is handled correctly using JavaScript's built-in Date object.
Can I calculate age on a future date?
Yes — change the second date to any future date and the calculator will tell you how old you'll be then.
Why are total months and total days different from years × 12 / × 365?
Months and years are not uniform. The "total months" is years × 12 + extra months, and "total days" is the actual number of days in the calendar — which depends on whether your span included leap days.
Can I use this for pets?
Absolutely. Enter the pet's birth date and you'll get its age in human-calendar units. For "dog years" you'd need a separate conversion formula.