Calcwise / Time and dates / Age calculator
Age calculator
Enter a date of birth and a date to measure to. It starts on today's date.
Calculated in your browser. Nothing you enter is sent or stored.
About this tool: Age calculator
The calculator gives your age as whole years, months and days, the total number of days lived, and the countdown to the next birthday. Change the second date to see how old someone was or will be on a given day.
Someone born on 29 February celebrates on 28 February in years that are not leap years, and the tool counts it that way.
Formula
Age = whole calendar years, then months, then days between the date of birth and the chosen date. Days to the next birthday = days from the chosen date to the next anniversary of the birth date.
Worked example
Born 15 May 1990, measured on 2 November 2026: 36 years, 5 months and 18 days, which is 13,320 days lived, with 194 days to the next birthday.
Sources and data
- Formulas and data last reviewed
- Accuracy
- The result is plain maths: with valid input it is exact, and we only round to cents.
Frequently asked questions
Why is my age in days so large?
A year has 365 or 366 days, so 36 years is about 13,100 days. The exact figure depends on the leap years in between.
Can I check age on a past or future date?
Yes, change the second date. The date of birth must be on or before it.
Is my date of birth stored?
No. Everything is calculated in your browser and nothing is sent or saved.