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Age Calculator by Date of Birth

Calculate exact age in years, months, and days, plus total days lived and a countdown to your next birthday.

Runs entirely in your browser — your files are never uploaded to a server.

Last updated

This tool processes your input entirely in your browser. Nothing is sent to our servers.

How It Works

1. Choose Your File

Drag & drop or select the file you want to work with.

2. Processed in Your Browser

Everything happens locally on your device — your file is never uploaded anywhere.

3. Download Your Result

Get your finished file instantly, ready to save or share.

About Age Calculator by Date of Birth

Calculating someone’s exact age — not just years, but the precise number of years, months, and days between two dates — comes up for legal, administrative, or simply curious purposes more often than a rough estimate suffices.

This tool calculates precise age between any two dates, correctly accounting for leap years and varying month lengths, which a simple manual subtraction often gets wrong.

Also useful for calculating the exact number of days until a specific future date (a birthday, an anniversary, a deadline), not just age between two past dates.

Frequently Asked Questions

How many days old am I?

Enter your date of birth and the calculator shows your age in years, months and days, plus total days, weeks and months. The as-of date defaults to today, so the Total Days figure is how many days old you are now.

How do I calculate age from a date of birth?

Subtract the birth year from the current year, then take one off if this year's birthday has not happened yet. Or just enter your date of birth here and get years, months and days instantly. Everything is calculated in your browser.

Can I calculate age on a specific date?

Yes. Use the Calculate Age As Of field to choose any date, past or future. This is handy for forms, school or sports cut-offs, and legal age checks. The as-of date must not be earlier than the date of birth.

Does it show how many days until my next birthday?

Yes. Below the age breakdown, the calculator displays the number of days until your next birthday, counted from the as-of date, and says so when the birthday falls on that date.

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