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Age Calculator

Calculate an exact age, or the days until any future date.

Years
Months
Days
Total days
Total weeks
Days to next birthday

About This Calculator

Enter a start date and (optionally) a different "as of" date to calculate the exact time between them — broken down into years, months, and days, plus the total number of days and weeks elapsed. Leave the second date as today to calculate a current exact age.

The "days to next birthday" figure uses the day and month of your start date to find the next anniversary from the "as of" date — useful for birthdays, anniversaries, or any recurring annual date.

Frequently Asked Questions

Does it account for leap years?

Yes — the calculation uses actual calendar dates via JavaScript's native Date object, which correctly accounts for leap years and varying month lengths.

Can I calculate the time between two dates that aren't birthdays?

Yes — enter any two dates; it works for calculating the time between any two events, not just age.

Why would I use a date other than today for "as of"?

To calculate someone's exact age at a specific past or future date — useful for legal, medical, or eligibility purposes where the exact age on a particular date matters.