Age calculator by date of birth
Get an exact age in years, months and days, the total days lived, and how long until the next birthday.
Runs entirely in your browser. Your dates are never sent anywhere.
Defaults to today. Change it to work out an age on any past or future date.
Next birthday
How to use the age calculator
- Enter the date of birth. The date field uses your device's own picker, so the format matches whatever your phone or computer is set to.
- Leave the second date as today for a current age, or change it to work out an age on a specific date — useful for eligibility cut-offs and school admission dates.
- Press Calculate age. The headline gives you years, months and days as a calendar age, which is the figure forms and applications ask for.
- The panels underneath give total months, weeks, days and hours, plus the countdown and day of the week for the next birthday.
What you can use it for
Eligibility cut-offs are the most common reason people need an exact age rather than an approximate one. Competitive exams, government job applications, school admissions and pension schemes all specify an age as of a particular date, and being three days over can disqualify an application. Setting the second date to the cut-off answers it definitively.
Forms that demand years, months and days will not accept a rounded figure. Visa applications, insurance proposals and several Indian government forms have three separate boxes, and working it out by hand across leap years is genuinely error-prone.
Date difference calculations serve a wider purpose than age. Put a project start date in the first field and a deadline in the second and you have the working duration in days, which is more useful than counting squares on a calendar.
The day-of-week result answers a question people ask surprisingly often: which day was I born on. It comes free with the calculation and is the sort of detail that makes a birthday message land.
How the calculation works
Age is calculated the way people count it, not by dividing total days by 365.25. The years are counted first, then the remaining whole months, then the leftover days. This is what forms mean by years, months and days, and it is why the numbers do not always match a simple division.
Leap years are handled by the calendar itself rather than by an average. The calculation walks real dates, so 29 February exists in the years it exists in and does not in the years it does not. That makes the total day count exact rather than approximate.
People born on 29 February have no birthday in most years. The convention in India and most other jurisdictions is to treat 1 March as the legal birthday in non-leap years, which is what the next-birthday countdown here does.
Everything is computed in your device's local time zone. If you are checking an age against a deadline in a different country, be aware that the date can differ by one day across time zones — a cut-off of 31 December in one place is already 1 January in another.
Frequently asked questions
Enter your date of birth and leave the second date as today. The calculation subtracts the years first, then the whole months remaining, then the days, walking the real calendar so leap years and differing month lengths are handled correctly. That is the same method a form expects when it asks for all three.
Yes. Set the second field to any date, past or future. This is the standard way to check eligibility, since almost every exam and application specifies an age as of a particular cut-off date rather than as of the day you apply.
In non-leap years the birthday is treated as 1 March for the countdown, which follows the usual legal convention in India and most other countries. The year count itself is unaffected — you still turn a year older annually.
Because leap years add an extra day roughly every four years. Over forty years that is about ten additional days. The total here counts real calendar days between the two dates, so it is exact rather than an approximation.
No. The calculation runs entirely in your browser and nothing is transmitted or saved. Refreshing the page clears everything, which matters given that a date of birth is personal information.