Skip to content
Work data is processed in your browser, not stored on our servers.
tools
Age, Birthday, and Elapsed Days Calculator

Age, Birthday, and Elapsed Days Calculator

Calculate completed age, exact elapsed time, elapsed days, and days until a birthday from a birth date and reference date.

Focus mode
Age calculator
Calculate completed age and elapsed time from a birth date and reference date. Everything runs only in your browser.

Enter both dates to see the result.

For a February 29 birth date, February 28 is treated as the birthday in non-leap years.

Key features

  • Calculates completed age plus exact calendar years, months, and days.
  • Shows elapsed days, day of birth, and days until the next birthday.
  • Uses February 28 for February 29 birthdays in non-leap years.

How to use

  1. Enter a birth date.
  2. Optionally change the reference date.
  3. Review the result calculated locally in your browser.

Examples

  • Check age on a specific date

    Enter a past or future reference date to find the completed age on that day.

  • Measure time since birth

    Review years, months, days, total elapsed days, and day of birth together.

Privacy

Dates and results are processed only in your browser and are not sent or stored.

Requirements

This is a calendar-date calculation; check local rules for legal or administrative age definitions.

Common questions

Can I use a reference date other than today?
Yes. Choose any reference date to calculate completed age, calendar duration, and elapsed days up to that date. A date before the birth date is not calculated.
How is a February 29 birthday handled in a non-leap year?
This tool uses February 28 in non-leap years. Legal or administrative rules can differ by jurisdiction.

Related tools