Age Calculator
Enter a date of birth to get an exact age in years, months and days, the total number of days lived, and how many days remain until the next birthday. Change the "as of" date to find an age on any day, past or future. Your dates stay in your browser.
How to Use the Age Calculator
- 1. Enter the date of birth. Use the date picker or type it. Nothing is calculated until a birth date is set.
- 2. Choose the "as of" date, or leave it blank. Blank means today. Set a past date to answer "how old was I on…", or a future date for "how old will I be on…".
- 3. Read the age. You get complete years, months and days, then the total days lived, the days until the next birthday, and the weekday that birthday falls on.
- 4. Check the order. If the "as of" date is earlier than the birth date, the tool says so instead of showing a negative age.
How Exact Age Is Calculated
The calculator subtracts the birth date from the "as of" date field by field. It counts complete years first, then complete months, then the remaining days. If the day of the month is smaller than the birth day, it borrows one month and adds the length of the month before the "as of" date, using the real calendar length — 28, 29, 30 or 31 days.
Born on 31 August 1990, you are 36 years, 1 month and 16 days old on 17 October 2026: 17 − 31 is negative, so a month is borrowed and September's 30 days are added, giving 16. The total-days figure ignores months entirely — it is the plain number of calendar days between the two dates.
| Date of birth | As of | Exact age | Days lived | Next birthday |
|---|---|---|---|---|
| 1990-05-15 | 2026-10-17 | 36y 5m 2d | 13,304 | Sat 2027-05-15, in 210 days |
| 1990-08-31 | 2026-10-17 | 36y 1m 16d | 13,196 | Tue 2027-08-31, in 318 days |
| 2005-03-10 | 2026-10-17 | 21y 7m 7d | 7,891 | Wed 2027-03-10, in 144 days |
| 2010-10-17 | 2026-10-17 | 16y 0m 0d | 5,844 | today, in 0 days |
Born on 29 February
A leap-day birthday has no anniversary in three years out of four. This calculator treats 1 March as the birthday in a non-leap year: someone born on 29 February 2000 is 24 years, 11 months and 30 days old on 28 February 2025 and exactly 25 years old on 1 March 2025, and their next birthday from 17 October 2026 is Monday 1 March 2027, 135 days away.
That is a convention, not a law of nature. Some places and organisations move the birthday to 28 February instead, so where an exact legal age matters — a driving licence, a pension date, an age-restricted purchase — check the rule that applies to you.
Which Tool Do You Need?
| You want to… | Use |
|---|---|
| Know how old someone is, or will be on a date | This calculator |
| Count days, weeks or business days between any two dates | Date Calculator |
| Find the weekday someone was born on | Day of the Week Calculator |
| Add or subtract hours and minutes | Time Calculator |
| Work out your age on other planets | Age on Other Planets Calculator |
Frequently Asked Questions
- How do I calculate my age from my date of birth?
- Enter your date of birth and read the Years, Months and Days cards. They count the complete years since you were born, then the complete months since your last birthday, then the leftover days. Leave the "as of" date blank to use today.
- How old will I be on a future date?
- Type that date into the "as of" field. The calculator gives your exact age on that day, together with the total days lived by then, which is handy for a milestone birthday, a school cut-off date or an eligibility deadline.
- How many days old am I?
- Look at the Total days lived card. It is the number of calendar days from your date of birth to the "as of" date, calculated in UTC so time zones and daylight saving changes cannot add or remove a day. Someone born on 15 May 1990 has lived 13,304 days on 17 October 2026.
- How many days until my birthday?
- The Days until next birthday card counts from the "as of" date, which is today unless you change it, to your next birthday, and the card beside it names the weekday and date. If today is your birthday, the countdown shows 0.
- How are leap years and 29 February birthdays handled?
- The months and days breakdown uses real month lengths, including 29 days in February of a leap year. For the next-birthday countdown, a 29 February birthday is moved to 1 March in non-leap years. Laws and policies vary, so check the rule that applies to you for legal ages.
- Is my date of birth stored or sent anywhere?
- No. The calculation runs in your browser, and nothing you enter is uploaded or saved by the tool.