Как рассчитать возраст по дате рождения

To calculate age from a date of birth, count the full years since the birth date, then the full months since the last birthday, then the days left over. The free age calculator does it for you: enter the date of birth, and it shows the exact age in years, months and days, plus total months, weeks and days and how long until the next birthday. You can also find the age on any other date, such as an exam form's cut-off date.

Как это сделать use the age calculator

1. Open the free age calculator.
2. Enter the Date of birth.
3. Leave Age on as today, or pick another date.
4. Read the age in years, months and days.

Below the main answer you'll see Total months, Total weeks, Total days and Next birthday, plus the day of the week the person was born on. Nothing you enter is sent anywhere; the calculation happens on your device.

A worked example

Say someone was born on 15 August 1990, and today is 28 October 2026:

1. Full years. Their 36th birthday was on 15 August 2026, which has passed. So they're 36.
2. Full months. From 15 August 2026 to 15 October 2026 is 2 full months.
3. Days. From 15 October to 28 October is 13 days.

So the age is 36 years, 2 months and 13 days. The calculator also shows 434 total months, 1,889 total weeks, 13,223 total days, a next birthday in 291 days, and that they were born on a Wednesday.

Why simple subtraction goes wrong

The quick method, subtracting the birth year from the current year, only works after this year's birthday. Someone born in December 2000 is not 26 in October 2026; they're still 25 until December.

Dividing total days by 365 goes wrong too, because leap years add a day every four years. Over a lifetime that adds up, and near a birthday it can give the wrong whole number. Counting full years, then months, then days, the way people count birthdays, avoids both problems.

Age on a cut-off date (exams, jobs and schools)

Many applications don't ask how old you are today. They ask how old you are as on a fixed date: "age as on 1 January 2026" or "as on 1 August of the admission year". Eligibility rules then say something like "at least 18 and not more than 27 years".

To check:

1. Enter your date of birth.
2. Change Age on to the cut-off date from the official notice.
3. Read the years, months and days.

For example, someone born on 1 June 2008 is 17 years, 7 months and 0 days old as on 1 January 2026.

Each exam, school or employer sets its own rules: whether a birthday on the cut-off date counts, which document proves your date of birth, and whether any category gets age relaxation. Always check the official notice. If you need to count the days between two dates rather than an age, the free date calculator does that, and the guide on calculating days between two dates explains how.

Born on 29 February?

A 29 February birthday only comes round in leap years. In other years, the calculator counts the birthday on 28 February, the last day of February. So someone born on 29 February 2004 turns one year older each year on 28 February, except in leap years, when it's 29 February. Some legal systems use 1 March instead for official purposes, so if it matters legally, check the local rule.

How months and days are counted

Months have 28 to 31 days, so "1 month" isn't a fixed number of days. The calculator counts calendar months: from the 15th of one month to the 15th of the next is one month, whether that's 28 or 31 days.

When the birth date is on a day the month doesn't have, such as the 31st, it uses the last day of the shorter month. Someone born on 31 January reaches each new month on the last day of months with fewer days.

Total days, by contrast, is exact: it's the actual number of days between the two dates, leap days included. Total weeks is total days divided by 7, rounded down.

Other uses

• Baby's age in weeks or months. Parents and doctors often use weeks for the first few months, then months until age two. Total weeks and total months are right there.
• Age difference between two people. Enter the older person's date of birth and set Age on to the younger person's date of birth.
• Age on a future date. Find out how old you'll be at a wedding, on a retirement date, or when a policy matures.
• Pet ages, anniversaries and work tenure. Enter the start date as the "date of birth" to get years, months and days since.
• Countdown to a birthday. Next birthday shows how many days are left.

If your next task is a percentage, for example for exam marks, see how to calculate percentage of marks.

Find an age now

Enter a date of birth in the free age calculator to see the exact age, or change the Age on date to check an eligibility cut-off. It's free and needs no sign-up.