Age Calculator — Your Exact Age in Years, Months & Days
Enter a date of birth and see your exact age, totals, and birthday countdown.
Enter your date of birth to see your age.
What is age calculator?
The age calculator takes a date of birth and a reference date (defaulting to today) and breaks the elapsed time into years, months, and days using exact civil-date arithmetic. Every month is counted by its actual length — 28, 29, 30, or 31 days — so there is no rounding, and leap years are handled correctly throughout.
Beyond the years/months/days breakdown, the tool also surfaces the total count of days, weeks, and nominal hours you have been alive, the weekday you were born on, and a countdown to your next birthday with its day of the week. If your birthday falls on February 29, the next-birthday field automatically shows February 28 in common years.
All calculations run locally in your browser. The dates you type never leave your device — there is no server call, no analytics on input values, and no data stored between sessions.
When to use a age calculator
- Exact age for forms and applications — Government forms, insurance applications, and medical records often require your age in years, months, and days. Enter your date of birth and any reference date to get the exact breakdown — no mental arithmetic required.
- Birthday countdown and planning — Find out exactly how many days until your next birthday, and which day of the week it falls on. Useful for planning celebrations or simply satisfying curiosity about the upcoming milestone.
- What day of the week was I born? — The calculator shows the full weekday name for any date of birth — useful for trivia, personal history, or settling family debates about whether you were born on a Tuesday.
- Age gap between two past dates — Set both the 'date of birth' and the 'age at' fields to any two historical dates to compute the exact elapsed time. Handy for genealogy research, historical comparisons, or academic timelines.
- Age-eligibility checks — Need to verify if someone has reached 18 for voting, 21 for legal purposes, 62 for early retirement, or 65 for Medicare eligibility? Enter the birth date and the relevant cutoff date to get a definitive answer.
How to use the Age Calculator — Your Exact Age in Years, Months & Days
- Enter your date of birth — Click the first date field and type or pick a date using the calendar popup. The calculator accepts any date back to the earliest years your device supports.
- Optionally change the 'age at' date — The second field defaults to today's date automatically. Change it to any past or future date to calculate age as of that moment — useful for historical lookups or planning ahead.
- Read your age and totals, then copy the summary — Your age appears instantly in years, months, and days. Scroll down for total weeks, total days, total hours, the day of the week you were born, and a countdown to your next birthday. Hit 'Copy summary' to grab the full multi-line result for pasting anywhere.
Worked examples
Born January 1, 2000 — age on May 28, 2026
Input: Date of birth: 2000-01-01 / Age at: 2026-05-28
Output: 26 years, 4 months, 27 daysThe breakdown uses exact civil-date arithmetic — each month counts its actual number of days, so leap years are handled correctly.
Leap-day birthday — Feb 29, 2000 — age on January 1, 2026
Input: Date of birth: 2000-02-29 / Age at: 2026-01-01
Output: 25 years, 10 months, 3 days — next birthday shown as February 28, 2026When the birthday falls on Feb 29, the calculator advances it to Feb 28 in common years for the countdown.
How many days old am I? Born June 1, 1990
Input: Date of birth: 1990-06-01 / Age at: 2026-05-28
Output: 13,145 days old (1,877 weeks)Total days and weeks are shown alongside the years/months/days breakdown for a different perspective on elapsed time.
Frequently asked questions
How is age calculated?
Does it count leap years correctly?
What day of the week was I born?
Date object is created solely for weekday lookup, so it is not affected by timezone offsets.