Most of us know our age in years, but forms, admissions and job applications often want more: your exact age in years, months and days on a particular date. Getting it wrong by a day can cost you an eligibility deadline. This guide shows how to calculate age from date of birth step by step, and how to do it instantly with our free Age Calculator.
The basic method
Age is the time between your date of birth and a target date, usually today. You count it in three layers:
- Years: how many full birthdays have passed.
- Months: how many full months since your last birthday.
- Days: the days left over after the last full month.
Worked example
Date of birth: 14 March 2001. Target date: 10 October 2026.
- From 14 March 2001 to 14 March 2026 is 25 years.
- From 14 March 2026 to 14 September 2026 is 6 months.
- From 14 September to 10 October is 26 days.
So the age is 25 years, 6 months and 26 days.
When you need to “borrow” days
If the target day is smaller than the birth day, you borrow days from the previous month. For example, born 28 June 1998, age on 5 April 2026:
- Years: 27 (last birthday 28 June 2025)
- From 28 June 2025 to 28 March 2026 is 9 months
- From 28 March to 5 April is 8 days (March has 31 days)
Result: 27 years, 9 months, 8 days. The number of days in the borrowed month matters, which is where hand calculations usually go wrong. An Age Calculator handles every month length and leap year automatically.
Leap-year birthdays
People born on 29 February only have a real birthday every four years. Legally, most countries treat 28 February or 1 March as the birthday in other years. When counting age in years, the calculator treats you as a year older from 1 March in common years, which matches how most official systems work. You can check which years are leap years with our Leap Year Checker.
Age on a specific date
Many forms ask for your age “as on” a cut-off date, for example the last date of applications. Instead of today, enter that date as the target date. This is common in:
- Government job adverts that set minimum and maximum ages
- School and university admissions with age limits
- Sports trials and scholarship schemes
Our guide on age limits for government jobs explains how cut-off dates work in more detail.
Total days, weeks and hours lived
Besides years, months and days, the age calculator shows your age as total days, weeks and even hours. These numbers are fun, but they are also useful: some insurance and medical forms ask for age in days for infants. If you want to count days since any other event, the Days Since Calculator calculator does the same job for any date.
Quick reference
| Born | Age on 10 October 2026 |
|---|---|
| 1 January 2000 | 26 years, 9 months, 9 days |
| 15 August 1990 | 36 years, 1 month, 25 days |
| 29 February 2004 | 22 years, 7 months, 11 days |
Frequently asked questions
How do I calculate my exact age?
Count full years since your birth date, then full months since your last birthday, then the remaining days. An age calculator does all three instantly.
Does the age calculator include today?
It counts the time between the two dates, so your age changes at the start of your birthday.
How is age calculated for someone born on 29 February?
In common years most systems treat 1 March as the day you turn a year older; the calculator follows that rule.
Can I calculate age on a past or future date?
Yes. Change the target date to any date to see your age on that day.