Age Calculator
Exact age from a date of birth, today or on any date.
Using toolbook means you agree to our Terms and Privacy Policy.
Defaults to today. Change it to work out an age on any other date.
Enter a date of birth to calculate an exact age.
Your files stay on your device
How to use it
Enter a date of birth to see the exact age in years, months, and days, plus total days lived and when the next birthday is.
Enter a date of birth and the exact age appears in years, months, and days — plus how many months, weeks, and days that is in total, and when the next birthday falls.
Want an age on a different date? Change “age on”. Handy for school year cut-offs, sports age groups, or working out how old someone will be at a wedding.
Born on 29 February? In non-leap years, your birthday is counted as 28 February (the usual rule in the UK and US). Some countries use 1 March instead, so check if it matters for something official.
Related: make a countdown to a birthday or find what weekday it falls on.
FAQ
How do I work out my exact age?
Enter your date of birth. Your age appears in years, months, and days, as of today unless you change the date.
How old am I in days?
It’s shown next to the main result, counting every leap day.
What about a 29 February birthday?
In non-leap years, it’s treated as 28 February, as in the UK and most of the US.
Can I check an age on a past or future date?
Yes. Change the “age on” date.
Is my date of birth saved or sent anywhere?
No. It’s worked out on your device and forgotten when you close the page.
How it worksFor the curious
Age is counted in whole calendar months from the birth date, then the remainder in exact days — how birthdays work, rather than elapsed 365-day years. It is the same years-months-days arithmetic as the date difference calculator.
The 28 February convention for leap-day birthdays is used in the UK and most of the US; parts of continental Europe and New Zealand use 1 March. The tool says on screen when it applies.
Total days is an exact count of calendar days including every leap day. Hours are that count × 24, so across daylight saving changes they can be an hour or two out from true elapsed time.