The age calculator works out exactly how old someone is in years, months and days on any date. It also shows the total number of months, weeks and days lived and counts down to the next birthday. Leave the second date as today, or change it to find someone’s age on a past or future date, such as an exam cut-off or a visa application.
How to use it
- Enter the date of birth.
- Leave “Age on this date” as today, or pick another date.
- Click “Calculate age” to see the full breakdown.
How age is calculated
The calculator counts complete years first, then complete months, then the remaining days. When a month is shorter than the birth day, the monthly anniversary falls on that month’s last day, so someone born on 31 January is one month old on 28 February (or 29 February in a leap year). Any days after the last full month are counted as remaining days.
People born on 29 February have a birthday only in leap years. In other years this calculator treats 1 March as the next birthday, which is the convention used in many countries, including the UK, for legal age.
Frequently asked questions
Can I calculate age for a future date?
Yes. Set the second date in the future to see how old you will be then, for example on the day of a competition or retirement.
Does it count leap years?
Yes. Total days lived uses the real calendar, so every 29 February in the period is included.
Is my date of birth stored?
No. The calculation runs in your browser and nothing is saved or sent.