Age / Date Calculator
Calculate your exact age or the difference between two dates in years, months, and days, plus total days. Free, instant, and private.
Work out an exact age, or the gap between any two dates, broken down into years, months and days, plus the total number of days. It is built for the cases where a round number will not do: a form that asks for years and months, a visa or benefits threshold measured on a specific date, a project timeline, or simply how long it has been since something began. The result updates as you change either date, and the calculation happens in your browser.
How to use Age / Date Calculator
- Pick a start date, such as a birthday or the start of an agreement.
- Leave the end date as today, or choose a different date to measure backwards or forwards from.
- Read the result as years, months and days, with total days underneath.
- Change either date to compare a different pair — nothing is submitted, so a mistake costs one edit.
Who it is for
Age Calculator is for an exact age or an exact gap: a form that asks for years and months, a visa or benefits application with an age threshold on a specific date, a project timeline, or simply how long it has been since something happened.
How it works
- Two dates are compared and the difference is broken into years, months and days, plus total days.
- The breakdown accounts for month lengths and leap years, which is why it can differ from dividing total days by 365.
- The calculation happens in the browser against the dates you enter.
What it cannot do
- Age conventions differ: some legal systems count a person as a year older on the day before their birthday, and this tool does not apply that rule.
- It works on calendar dates, not times of day, so a birth time cannot shift the result.
- Timezone is your device's, which matters only if you are comparing dates far apart in different zones.
- It does not handle historical calendar reforms, only the current Gregorian calendar.
Frequently asked questions
How is the age calculated?
The tool counts complete years and months from the start date, then the remaining days — the same way you would naturally say someone is "34 years, 2 months, and 5 days" old. It walks a cursor forward from the start rather than subtracting month numbers, because subtracting fields directly can produce a negative day count.
Does it handle leap years?
Yes. Month lengths and leap days are accounted for, so results stay correct across February and leap years. A month-end is clamped to the target month's length, so 31 January plus one month is 28 February, not an overflow into March.
Can I calculate a future date difference?
Yes. Set the end date later than the start date to count down to an event, or use any two dates to measure the span between them.
Why does the day count not match dividing total days by 30?
Because months are not equal lengths. The breakdown follows the calendar, so three months from January is 90 days and three months from February is 89 or 90 depending on the leap year. Total days is the figure to use for arithmetic.
Is this the legal way to state an age?
Not necessarily. Some legal systems count a person as a year older on the day before their birthday, and different jurisdictions define an age threshold differently. Use the number here as the calendar difference, not as a legal determination.
Is my date information private?
Yes. The dates you enter are processed locally in your browser and never sent anywhere, which matters if the dates identify a person.