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Age Components Calculator

Break an age down into completed years, months and days from a date of birth, plus total months, weeks and days. Hours and minutes are not calculated.

Version 2

Things to keep in mind:

  • The tool does not calculate hours or minutes; it works with calendar dates only.
  • The reference date must not be before the date of birth.
  • In official procedures (retirement, age limits, military service etc.) age calculation follows the relevant legislation; verify the result.
  • Today’s date is not picked up automatically; you enter the reference date.

Calculator

Dates

Birth date of the person whose age is calculated.

The date at which age is calculated (usually today). Must not be before the date of birth.

After the first calculation, the result updates automatically when you change a value.

Result

Enter the values and press Calculate to see the result here.

About this tool

This tool splits the age between a date of birth and a chosen date into completed years, months and days and also gives the total months, weeks and days.

Logic

  • Years: the largest n such that adding 12 × n months to the birth date does not pass the target date.
  • Months: whole months that can be added after the whole years (0–11).
  • Days: days from the last whole month to the target date. At month ends the day is clamped to the last day of the target month.
  • Total months = years × 12 + months; total days = reference date − birth date; total weeks = ⌊days / 7⌋.

Example: someone born on 15 January 2000 is 24 years, 2 months and 5 days old on 20 March 2024 (290 total months). Someone born on 29 February 2000 is 21 years 0 months 0 days on 28 February 2021 (28 February counts as the birthday in non-leap years).

Hours and minutes: the tool works with calendar dates only; there is no time of day or birth time in the calculation engine, so it does not calculate age in hours or minutes. For an approximation you can multiply the total days by 24 (approximate, since the birth time is unknown).

How to use

  1. Pick the date of birth.
  2. Pick the reference date (enter today).
  3. Press Calculate.
  4. Read the years, months and days.

Notes

Age is calculated with completed years/months/days logic; for 29 February births 28 February counts as the birthday in non-leap years. Hours and minutes are not supported (dates only). If the reference date is before the birth date the result is meaningless.

Frequently asked questions

4 questions
  1. Enter your date of birth and today’s date; the tool returns completed years, months and days separately.

Next step

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