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How to Calculate Exact Age

What is Exact Age?

An exact age calculator computes your precise age in years, months, days, hours, and even seconds from your date of birth to the current moment. This is more complex than it appears because months vary in length (28–31 days) and leap years add an extra day every 4 years.

Step-by-Step Guide

  1. 1Start with today's date minus birth date
  2. 2If day of month < birth day, borrow from the previous month and subtract 1 month
  3. 3If month < birth month after adjustment, borrow from the year and subtract 1 year
  4. 4Convert total days to hours, minutes, and seconds for the precise figure

Worked Examples

Input
Born 15 March 1990, today 15 March 2025
Result
Exactly 35 years, 0 months, 0 days
Birthday today!
Input
Born 31 January 1990, today 1 March 2025
Result
35 years, 1 month, 1 day
Short month affects the calculation

Frequently Asked Questions

What is Exact Age?

An exact age calculator computes your precise age in years, months, days, hours, and even seconds from your date of birth to the current moment. This is more complex than it appears because months vary in length (28–31 days) and leap years add an extra day every 4 years

How accurate is the Exact Age calculator?

The calculator uses the standard published formula for exact age. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

What units does the Exact Age calculator use?

This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.

What formula does the Exact Age calculator use?

The calculator applies the standard formula for this type of calculation. See the 'How It Works' steps above for the detailed formula breakdown.

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