Age Calculator

The Age Calculator works out the exact time that has passed between a date of birth and any other date. By default that second date is today, so the result is your current age. You can change it to a past date to see how old you were on a wedding day or an exam date, or to a future date, for example the last date of an application form, to check whether you will meet an age limit.

The result follows the convention used on Indian birth certificates, passports and government forms: completed years, then completed months, then remaining days. Below it, the same span is shown as total months, weeks, days, hours, minutes and seconds. You also get the weekday you were born on, the countdown to your next birthday, your Western zodiac sign and your Chinese zodiac animal.

How to use the age calculator

1. Date of birth: choose the birth date from the date picker, or type it in. Any date from the year 1 onwards works, so you can also use it for historical figures.
2. Age at the date of: this is filled with today’s date. Change it if you need your age on a specific day, such as “age as on 1 January 2027”, which many recruitment notices ask for.
3. Press Calculate Age. The main figure is your age in years, months and days. The list underneath shows the same span in other units.

Everything runs in your browser. Your date of birth is not sent to our server or stored anywhere.

How age is calculated

In most of the world, including India, age goes up by one year on each birthday. A baby is 0 years old until the first birthday. The calculator follows that rule and counts the time in three steps:

When the day of the target date is earlier in the month than the birth day, a month is “borrowed”. The days in the month just before the target month are then added. Doing it this way means a month always ends on the same day number it started on, which matches how people count on a calendar.

Calculating your age by hand

To check the result on paper, write the target date above the birth date in the order year, month, day, and subtract column by column from the right:

If the month column goes negative, borrow 12 months from the year column in the same way.

Age in different units

Some situations need age in a single unit. Paediatricians track babies in weeks and months, insurance forms sometimes ask for age in days, and “how many seconds old am I?” is a popular birthday question. The calculator converts the exact number of days between the two dates:

• Total months + days: completed months since birth plus the remaining days. This is useful for infants and young children, whose milestones and vaccination schedules are given in months.
• Weeks + days: total days ÷ 7, with the remainder shown in days.
• Days: the actual number of calendar days, including every 29 February in the period.
• Hours, minutes, seconds: days × 24, × 1,440 and × 86,400. These assume midnight-to-midnight because no time of birth is entered, so take them as close approximations.

Leap years and 29 February birthdays

A year is a leap year if it is divisible by 4. Century years are the exception: they are leap years only if they are divisible by 400. So 2000 was a leap year and 1900 was not. Because the calculator uses real calendar dates instead of assuming 365 days a year, the extra day in each leap year is counted automatically.

People born on 29 February (“leaplings”) only see their exact birth date every four years. In a non-leap year, the calculator treats 1 March as the day the new year of age begins. That is when 365 days have passed, and it is also how age is usually treated for legal purposes in India and the UK. Some families celebrate on 28 February instead, which is fine for a party. For forms and eligibility, 1 March is the safer date to use.

End-of-month dates

Month-and-day results can be ambiguous when the start date falls at the end of a month, because months have 28, 29, 30 or 31 days. Take the span from 31 January 2026 to 31 March 2026:

• Counting by calendar months, it is exactly 2 months: January 31 to March 31.
• Counting by days, it is 59 days, because February 2026 has only 28.

When the start day does not exist in a later month (31 January has no 31 February), this calculator counts that month as ending on the last day of the shorter month. That method is predictable and matches common legal and banking practice. Other tools may count from the 1st of the next month and give a result that differs by a day or two. That is a difference of convention, not an error.

Age systems around the world

The “age goes up on your birthday” rule is standard almost everywhere today, but it is not the only system people have used.

East Asian age reckoning

Traditionally in China, Korea, Japan and Vietnam, a baby was counted as 1 year old at birth, and everyone gained a year together on Lunar New Year instead of on their own birthday. A baby born a few days before New Year could therefore be called 2 years old within a week of being born. South Korea officially moved to the international system for legal and administrative purposes in June 2023, but the traditional count is still used in conversation and for some customs. The calculator shows an approximate East Asian age as the number of calendar years you have lived in (current year − birth year + 1).

Indian traditions

In many Indian households, a child’s first birthday celebrates the completion of the first year. For religious purposes, some families follow the janma tithi, the lunar date of birth in the Hindu calendar, which falls on a different Gregorian date each year. For official purposes, including school admission, Aadhaar, passports, PAN and government recruitment, only the Gregorian date of birth on your certificate counts, which is what this calculator uses.

Age limits that matter in India

People often look up their exact age because a rule or form sets an age cut-off. Common ones are below. Check the latest official notification before you rely on any of them, because rules and relaxations change.

Other things the result tells you

The day of the week you were born

The calculator gives the weekday of your birth. Many people find this interesting, and it is also handy for horoscopes, naming ceremonies or just settling a family argument. The 15 August 1995 example above fell on a Tuesday.

Next birthday countdown

You will see the date of your next birthday, the weekday it falls on and how many days are left. If the target date is your birthday, the calculator says so.

Zodiac signs

The Western (tropical) zodiac sign comes from your birth month and day. For example, someone born between 23 July and 22 August is a Leo. The Chinese zodiac runs in a 12-year cycle of animals. It changes at Lunar New Year, which falls between 21 January and 20 February, so if you were born in January or early February, your animal may belong to the previous year. Vedic astrology uses a sidereal zodiac that is shifted by roughly 23–24 days, so your rashi can differ from the Western sign shown here.

Common questions about age calculation

Why do two age calculators give different answers?

The usual reasons are the end-of-month rule described above, whether the end date is counted as a full day, and time zones. Some websites treat dates as UTC midnight, which can shift a date by one day for users outside the UK. This calculator reads dates in your own local time, so the day you enter is the day it uses.

Is age counted on the birthday or the day after?

You complete a year of age at the start of your birthday. On 15 August 2026, a person born on 15 August 1995 is exactly 31 years, 0 months and 0 days old.

Can I work out the time between any two dates?

Yes. The tool works for any two dates, not just birthdays: the age of a company, how long you have been married, or the length of a job. For working days, deadlines or adding days to a date, our Date Difference Calculator, Working Days Calculator and Date Calculator have more options.

Frequently asked questions