Age Calculator
Enter your date of birth to see your exact age in years, months, and days — plus fun extras like your total days lived and how long until your next birthday.
How this age calculator works
Your age is calculated the way most of the world does it: you turn one year older on each birthday. The calculator counts full years first, then full months since your last birthday, then the remaining days. It handles leap years and different month lengths automatically, so the result is exact.
For example, someone born on March 15, 2000 is, on July 2, 2026, exactly 26 years, 3 months, and 17 days old.
What about leap-year birthdays?
If you were born on February 29, you have a real birthday only once every four years. Legally, most countries treat your birthday as March 1 (or February 28, depending on the jurisdiction) in non-leap years. This calculator counts a completed year when the calendar reaches the last day of February in non-leap years.
Fun ways to read your age
- Days lived: a 30-year-old has lived roughly 10,957 days.
- 10,000-day birthday: falls at about age 27 years 4½ months — a popular modern milestone.
- Heartbeats: at an average 70 beats per minute, each year of life is about 36.8 million heartbeats.
"How old am I" has more than one correct answer
The figure above is international age — complete years lived, the reckoning used on passports, in almost all law, and by every medical guideline. It is what you want unless someone has told you otherwise. But it is not the only system in use, and the difference is not small:
| System | How it counts | Someone born 20 Dec 2000, on 1 Jan 2026 |
|---|---|---|
| International | Completed years since birth | 25 |
| East Asian age | Born at 1; everyone gains a year at New Year | 27 |
| Korean "year age" | Current year minus birth year | 26 |
| School or fiscal-year age | Age as of a fixed cutoff date, not your birthday | Whatever the cutoff says |
A person can therefore be 25, 26 or 27 on the same day depending on which convention is being applied, and the gap is widest for people born late in the year. South Korea standardised on international age in law in June 2023 precisely because the ambiguity caused real problems in contracts, medical records and administration — though the traditional counts survive in conversation, and the year-age rule still governs a few things such as school entry and the legal drinking age.
If a form asks for your age and does not say which system it means, it means international age. This calculator gives you that.
Why "months" is the fuzziest part of the answer
Years and total days are unambiguous. Months are not, because months are not the same length, and the answer depends on which order you subtract in. Take 31 January to 1 March: is that one month and one day (31 Jan → 28 Feb, then one more day), or is it 29 days? Both are defensible, and different tools give different results.
This page uses the convention almost every calendar and legal system uses: count whole months first, then the leftover days, clamping the start day to the length of the month you land in. It is the reading that makes "one month later" mean the same date next month whenever such a date exists. The total days figure is offered alongside it for exactly this reason — when the answer needs to be unarguable, count days.
Frequently asked questions
How is my exact age calculated?
Completed years are counted from birthday to birthday, then completed months from the last birthday, then leftover days. Leap years and 28/29/30/31-day months are all handled by the calendar itself.
Why do two calculators sometimes give slightly different ages?
The "months and days" remainder can be counted in more than one way when the start day doesn't exist in the target month (e.g., the 31st). Differences are at most a day or two, and the year count is always the same.
Can I calculate age at a past or future date?
Yes — set the "Age as of" field to any date, such as the day of an exam, a wedding, or a historical event.
Does the calculator store my birth date?
No. Everything runs in your browser; nothing is sent to a server.