Age Calculator

Using the calculator

You fill in two dates and press one button.

1. Date of Birth — pick the birth date. Only the date is used. There is no box for the time of birth.
2. Calculate to Date — this box is filled in when the page opens. Change it to find an age on another day, for example the closing date of a job application or an exam age rule.
3. Press "Calculate Age". If a date is missing, you see "Select dates". If the birth date is after the target date, you see a message and no result.

You get nine results:

• Years, Months, Days — the age in the usual form, such as 36 years, 4 months and 15 days.
• Total Months — years × 12 + months. The leftover days are not counted.
• Total Weeks — total days ÷ 7, rounded down.
• Total Days — the number of calendar days between the two dates. Leap days (29 February) are included.
• Total Hours and Total Minutes — total days × 24 and total days × 1,440. They count from midnight to midnight, because the tool does not know what time you were born.
• Next Birthday — the number of days from the target date to the next birthday after it.

How years, months and days are counted

The tool counts whole months first, then the days left over:

1. It steps forward from the birth date one month at a time. It stops at the last monthly birthday that is on or before the target date.
2. The whole months become years and months. 12 months make 1 year.
3. The days from that last monthly birthday to the target date are the Days.

If a month is too short for the birth day, the last day of that month counts. For example, one month after 31 January is 28 February, or 29 February in a leap year.

Worked example 1: no borrowing needed

Worked example 2: borrowing days from February

Birthdays at the end of a month

There is no 31 February, so "one month after 31 January" has no single right answer. This tool uses the last day of the shorter month. The table shows what it gives for some month-end dates.

Other calculators may count these cases in a different way, for example 31 January to 28 February as 0 months and 28 days. Total Days is the same in every method, so use it when an exact count matters.

Leap-day birthdays (29 February)

In a year without 29 February, the tool treats 28 February, the last day of February, as the birthday. Here is what it shows for someone born on 29 February 2000:

• On 27 February 2026: 25 years, 11 months, 29 days. Next Birthday: 1 day.
• On 28 February 2026: 26 years, 0 months, 0 days.
• On 29 February 2028, a leap year: 28 years, 0 months, 0 days.

Rules for leap-day birthdays differ between countries and organisations. Some count 28 February as the birthday in a normal year, and others count 1 March. If the exact day matters, for example for a legal age limit, check the rule that applies to you.

Time zones and the date the tool uses

• Only dates are compared. Use the date on your birth certificate. The place where you were born does not change the result.
• The result is the same everywhere. The tool compares plain calendar dates, so the time zone of your computer does not change Years, Months, Days or Total Days.
• The Calculate to Date box starts at today, using the date on your own device. Change it if you need your age on another day.

Common mistakes

• Leaving the target date at today. Many school, exam and job rules ask for your age on a fixed date, such as 1 January or the last day to apply. Set Calculate to Date to that day.
• Mixing up day and month. The date box follows your device's date format. 03/04/2000 can mean 3 April or 4 March. Use the calendar picker if you are not sure.
• Reading Total Months as exact. It drops the leftover days. 36 years, 4 months and 15 days shows as 436 months.
• Expecting other age systems. The tool uses the international system, where a baby is 0 years old at birth. It does not calculate traditional East Asian age counting.