How Age Calculator Works
The calculator takes the date you were born and the date you want to measure against (today, by default) and works out the calendar-accurate difference between them. Rather than simply dividing total days by 365, it counts full years, then full months within the remaining time, then the leftover days — so the result matches how age is normally described.
How to Use This Tool
- Enter your date of birth in the first field.
- Optionally change the second date if you want your age on a date other than today.
- Select Calculate Age to see your age broken down into years, months and days.
- Scroll the result box for totals in months, weeks, days, hours and minutes, plus days until your next birthday.
Example
Someone born on 14 March 2000, calculated as of 20 August 2026, is 26 years, 5 months, 6 days old — that's 317 months, 1,379 weeks, and 9,655 days.
Helpful Tips
- Use the "Calculate age as of" field to work out how old someone will be on a future date, such as a wedding or graduation.
- The next-birthday countdown is useful for planning ahead — it updates automatically based on the date you enter.
- Age in months and weeks can be handy for tracking a baby's development milestones.
Frequently Asked Questions
How is age calculated exactly?
The tool counts full years between the two dates, then full months in the remainder, then the leftover days — the same way people naturally state their age.
Can I calculate someone's age on a future date?
Yes. Change the "Calculate age as of" field to any future date to see how old someone will be on that day.
Does it account for leap years?
Yes, the calculation uses standard calendar dates, so leap years are handled automatically.
Is my birth date stored anywhere?
No. The calculation happens entirely in your browser and nothing is sent to a server.
This tool runs entirely in your browser. Your input is not uploaded to any server.