Decision instrument
Age Calculator
Calculate age
Your inputs
Adjust the fields and review the result in this workbench.
Interpretation
How Age Calculation works
The Age Calculator measures the calendar difference between a past birth date and today. It handles month-end and leap-day anniversaries by using the final valid day of the anniversary month.
Example
Key features
A realistic example to show how this tool can support an actual decision.
Formula
Age = today minus birth date, using calendar-month anniversaries
- Calculates age in calendar years, months, and days
- Accounts for leap years and varying month lengths
- Shows an approximate decimal-year view
- Rejects future dates
Avoid mistakes
Common mistakes
A few things that can lead to misleading results or poor decisions.
For legal, benefits, or eligibility decisions, verify the governing organisation's exact age-date convention.
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