How to Calculate Age on Date: Formula, Steps & Examples
Learn how to calculate Age on Date — the formula explained step by step, with worked examples and a free calculator to check your answer.
Age on Date Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Age in years
25.00
- Age in days
- 9,132
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Age on Date Calculator
The Age on Date Calculator works out your age in years, along with 1 related figure in an instant. Enter date of birth and date to calculate age on and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Pick the date of birth.
- Pick the date to calculate age on.
- Read off your age in years, together with age in days — the calculator updates automatically, with no button to press.
Formula
The Age on Date Calculator uses the formula:
Age in years = (Date to calculate age on - Date of birth) ÷ 365.25
Worked example
For example, with date of birth of 2000-01-01 and date to calculate age on of 2025-01-01, the age in years is 25.00.
| Date of birth | 2000-01-01 |
|---|---|
| Date to calculate age on | 2025-01-01 |
| Age in years | 25.00 |
|---|---|
| Age in days | 9,132 |
Results are estimates for educational use, not professional advice.
Frequently asked questions
Enter the date of birth and the target date. The calculator finds the days between them and divides by 365.25 for years.
The extra 0.25 accounts for leap years, giving a more accurate average year length over time.
A normal age calculator uses today's date. This one lets you pick any target date, past or future.
Yes. Choose a future target date to see how old someone will be on that day.
Pick the date of birth. Pick the date to calculate age on. Read off your age in years, together with age in days — the calculator updates automatically, with no button to press.