Exact Age Calculator
An exact age is not days ÷ 365: years, months and days must be compared separately. A one-day shift can matter for a competition entry, a fare bracket or a right that opens on a fixed date.
How an exact age is computed
Years, then months, then days are subtracted. If the current day of month precedes the birth day, the previous month's length is borrowed and a month removed. If the current month precedes the birth month, a year is removed and twelve months added.
This differs from days ÷ 365.25, which is an approximation: over decades the gap can reach several days — enough to matter when age is a legal condition.
When is an age reached?
Under French law, an age is reached on the birthday, at midnight. The rule matters for the age of majority, competition entries, benefit limits or retirement eligibility. Some texts set specific rules, notably retirement quarters, where the birth date fixes the timeline.
| Output | What the tool shows |
|---|---|
| Full age | Exact years, months and days as of today |
| Days lived | Total days since birth |
| Next birthday | Days remaining |
The February 29 case
A person born on February 29 has no birthday in common years. The most common convention treats March 1st as the birthday, but some texts use February 28. For an administrative act, check the applicable rule: this tool keeps the calendar birthday, which can shift the count by one day for February 29 births.
Reference points
- 1 year ≈ 365.25 days; 1 average month ≈ 30.44 days.
- At 20, about 7,300 days lived — roughly 1,043 weeks.
- At 40, about 14,600 days; at 60, about 21,900.
FAQ
How is an exact age computed?
Years, months and days are subtracted separately, borrowing from the higher unit when the birth day or month has not yet passed. Dividing a day count by 365 is only an approximation.
Does age change on the birthday or the day before?
Under French law, an age is reached on the birthday at midnight. Some specific texts provide other rules, notably for competitions and retirement.
Why use 365.25 days per year?
Because three years out of four have 365 days and the fourth 366. The four-year average is 365.25 days.
How old is someone born on February 29?
In common years the birthday is usually taken as March 1st, sometimes February 28 depending on the text. For administrative acts, check the applicable convention.