Age Calculator
Calculate exact age from a date of birth.
Please enter a valid date of birth that's on or before the “Calculate age as of” date.
Work out an age in years, months and days
Age Calculator counts the time between a date of birth and a second date — today, unless you change it — and gives the answer in whole years, months and days, along with totals in days, weeks and months.
It answers forms that ask for your age on a particular date, checks age cut-offs, or tells you how many days old you are. The dates you enter are used only in your browser and aren’t sent anywhere.
How to calculate age from a date of birth
- Enter the date in the Date of birth box.
- Leave Calculate age as of on today’s date, or change it to any other day — past or future — to find the age on that day.
- Click Calculate Age.
- If the date of birth is missing or later than the as-of date, a message asks for a valid date instead of showing a result.
What the age figures show
- Years, months and days: the age as people usually say it, such as 34 years, 2 months and 11 days. Months are calendar months, so they aren’t all the same length.
- Total days lived: the number of days between the two dates.
- Total weeks: the total days divided by seven, rounded down to whole weeks.
- Total months: complete calendar months only — the years multiplied by 12, plus the extra months.
When an age on a specific date matters
- Forms and applications: some ask for an age on a set date, such as the start of a school year or a competition deadline.
- Eligibility checks: confirm whether someone will have reached a minimum age by a given day.
- Milestones: see how many days old you are, or how many weeks old a baby is today.
- Family history: work out how old a relative was at a past event, such as a wedding or a census.
Getting the age you expect
- The as-of date is filled in for you, so glance at it before calculating — especially late at night — to make sure it shows the day you mean.
- For a future age, move the as-of date forward. It answers questions like “How old will I be on 1 September?”
- To turn a number of days into hours or minutes, use the Time tab of the Unit Converter.
Age Calculator: common questions
How is age counted for someone born on 29 February?
In years without a 29 February, the calculator treats the birthday as reached on 1 March: on 28 February the result is still 11 months and 30 days into the previous year of age. In leap years the age goes up on 29 February itself.
Can I calculate an age on a past or future date?
Yes. Set Calculate age as of to any date on or after the date of birth.
Does it show how long until my next birthday?
No. It reports the age on the as-of date only, not a countdown to the next birthday.
Why doesn’t total months equal total days divided by 30?
Calendar months run from 28 to 31 days, so the years, months and days figure follows the real calendar rather than a fixed 30-day month. Total months counts only months that are complete.
Is my date of birth stored?
No. It’s used for the calculation in your browser and isn’t saved or uploaded. You’ll find more everyday calculators in the same category.