Age Calculator
Enter a date of birth and get an exact age in years, months and days — plus total weeks, days and hours, and a countdown to the next birthday.
Defaults to today. Change it to find an age at a past or future date.
Exact age
Day you were born
Next birthday
About the Age Calculator
Working out an age in years is easy. Working out an age in years, months and days is where it gets awkward, because months have between 28 and 31 days and February gains one every four years — except in years divisible by 100, unless they are also divisible by 400. Most mental arithmetic quietly ignores all of that and lands a day or two out.
Precision matters more often than you would expect. Visa and immigration forms ask for age at a specific date. School enrolment cut-offs are decided to the day. Medical dosing for children is frequently age-banded. Insurance premiums step at exact birthdays, and some policies use the “age nearest birthday” convention rather than the age you would state yourself. Legal documents involving minors turn on a precise date.
This calculator does the calendar arithmetic properly. It counts calendar months rather than approximating them at 30 days, handles leap years including the century rule, and reports the result several ways: exact years, months and days; totals in months, weeks, days, hours and minutes; the day of the week you were born; and how long until your next birthday. You can also calculate age at a date other than today, which is what most official forms actually ask for.
How to use it
- Enter the date of birthUse the date picker or type it directly. Any date from the past is accepted.
- Optionally change the target dateLeave it as today, or set a future or past date to find the age as at that day.
- Read the exact ageYears, months and days, calculated with real calendar months rather than a 30-day approximation.
- Check the totalsThe same span expressed in months, weeks, days, hours and minutes.
- See the birthday detailsThe weekday you were born on and an exact countdown to your next birthday.
- Copy the summaryTake the full breakdown to your clipboard for a form or a document.
Features
- Exact calendar arithmeticReal month lengths and correct leap year handling, including the 100 and 400 year rules.
- Age at any dateCalculate age as at a past or future date, which is what most official forms require.
- Multiple unitsYears, months, weeks, days, hours and minutes for the same span.
- Birthday countdownDays remaining until the next birthday, and which weekday it falls on.
- Day of birthThe weekday you were born, calculated from the date rather than looked up.
- Nothing storedDates of birth are personal data. Everything is calculated locally and nothing is transmitted.
Who uses this tool
- Form fillingGive an exact age at a required date on a visa, pension, insurance or school application.
- ParentsTrack a child's age in months and weeks during the first years, when those units are what everything is measured in.
- HR and adminVerify age eligibility for a role, benefit or scheme at a specific effective date.
- CuriosityFind out how many days you have been alive, and which day of the week you were born.
Tips worth knowing
- For an age at a specific date — the deadline of an application, say — set the target date rather than using today's.
- Insurance often uses “age nearest birthday”, which can be one year higher than the age you would state. Check which convention a form wants.
- Total days is the fairest way to compare two people's ages, because it removes the distortion of different month lengths.
Frequently asked questions
How is exact age calculated?
By counting complete years first, then complete calendar months, then the remaining days — using each month's real length rather than an average. This is why the answer can differ from a simple subtraction that assumes 30-day months.
How are leap years handled?
Correctly, including the century rule: a year is a leap year if it is divisible by 4, except years divisible by 100, unless they are also divisible by 400. That is why 2000 was a leap year and 1900 was not.
What happens if someone was born on 29 February?
In non-leap years the birthday is treated as falling on 1 March for age purposes, which matches the convention used in most legal systems. The total-days figure is unaffected either way.
Can I calculate age at a future date?
Yes. Set the target date to any future day to find out how old someone will be then — useful for eligibility cut-offs, school enrolment dates and policy anniversaries.
Why does another calculator give a different result?
Usually because it approximates a month as 30 or 30.44 days rather than counting real calendar months. Over a long span that approximation drifts by several days. Total days should agree between any two correct calculators.
Is my date of birth stored anywhere?
No. The calculation runs entirely in your browser and nothing is transmitted or saved. A date of birth is personal data and is treated that way here.