“How old are you?” has a short answer. “How old are you exactly?” doesn’t, and anyone who has filled in a form that asks for age in years, months and days knows how fiddly the counting gets.
This age calculator needs just one thing from you: your date of birth. It always works out your age as of today, so there’s no second date to type in. You get the exact figure, the total in months, weeks, days and hours, the weekday you were born on and the countdown to your next birthday.
How to use the Age Calculator#
- Type the day. Enter your birth day as one or two digits, such as 7 or 07.
- Type the month. Enter the month as a number, for example 5 for May.
- Type the year. Use four digits, such as 1990.
- Read the result. Your age appears straight away, along with your totals and next birthday.
How your age is counted#
The calculator counts whole years first, then whole months, then the days that are left over. Take someone born on 15 May 1990 and look at them on 8 October 2026:
- From 15 May 1990 to 15 May 2026 is 36 full years.
- From 15 May 2026 to 15 September 2026 is 4 full months.
- From 15 September to 8 October is 23 days.
So the answer is 36 years, 4 months and 23 days. In days, that person has been alive for 13,295 days. They were born on a Tuesday, and their next birthday is 219 days away.
The awkward cases#
Months aren’t all the same length, which creates a few puzzles. Somebody born on 31 January has no 31 February to land on, so what’s their age one month later?
This calculator uses the common convention that a month is complete on the same day number, or on the last day of the month when that day doesn’t exist. A person born on 31 January turns “one month old” on 28 February in an ordinary year. A person born on 29 February is treated the same way in years without a leap day, and their birthday lands on 28 February. Different countries and different forms treat leap-day birthdays differently, so if the exact date matters for a legal reason, check which rule applies to you.
Years, months, weeks and days: where each one is useful#
Most of the time you want completed years. Forms for school entry, driving licences and pensions all use them. Months matter in a few places: baby milestones, the age of a pet, and some insurance and benefit rules. Weeks and days are popular for pregnancy dates, project milestones and plain curiosity (“how many days have I been alive?”).
If you need your age on a particular date in the past or future, such as a school cut-off day, work out the gap between the two dates by hand or ask the organisation which date they use. This tool measures to today.
Not everyone counts the same way#
The “completed years” method used here is the international standard. Some traditional systems in East Asia counted a person as one year old at birth and added a year every New Year. South Korea officially moved to international age counting in June 2023, which is a good example of how recently the difference mattered. When you fill in a form from another country, check which system it expects.
A quick way to sanity-check the answer#
Subtract the birth year from the current year. If your birthday hasn’t happened yet this year, take off one. That gives your completed years, and it should match the first number in the result. If it doesn’t, check that you typed the month and day in the right boxes.
Frequently asked questions#
Enter the day, month and year of birth in the calculator. It counts the complete years, then the complete months, then the leftover days up to today.
The “Total days” line shows it. For example, someone born on 15 May 1990 had lived 13,295 days by 8 October 2026.
The “Next birthday” line counts the days to your next birthday, and says Today if it’s happening now.
The result shows it under “Born on a”. It’s worked out from your date of birth, so it’s as reliable as the date you enter.
In years with no 29 February, the birthday is counted on 28 February. Legal systems vary, so check the rule for official purposes.
Multiply your whole years by 12 and add the extra months. Someone aged 36 years and 4 months is 436 months old. The calculator shows your age in years, months and days, plus the totals in months, weeks, days and hours, so you do not have to work it out by hand.