Birthday Calculator
How old someone is, on today or a date you pick.
LEAP YEAR ACCURATE - MULTIPLE FORMATS - RUNS ON YOUR DEVICE
Birthdays stay in this browser tab
- Y/M/Dyears, months, days
- Totaldays or weeks
- Leapyears counted
- Anydate to measure to
Birthday Calculator at a glance
- What you enter
- A birthday, and a date to measure to
- What you get
- Age in several formats
- Date to measure to
- Today, or any date you pick
- Leap years
- Real month lengths and leap days
- How many at once
- One age at a time
- Price
- Free
- Account required
- No
- Where it runs
- On your device
How to use Birthday Calculator
- 1
Enter the birthday
Pick the date of birth.
- 2
Choose the date to measure to
Keep today, or pick another date.
- 3
Read the age
Read the age and the totals.
Frequently asked questions
Can I see how old I will be on my next birthday?
Yes, by setting the second date to that day. The panel gives the age on any date you pick; it does not count down or remind you.
Why do the totals not match the years, months and days?
They are the same span written two ways. Years, months and days follows the calendar; total days is a plain count of days passed, which is 365 or 366 for a year.
Can I use it for something that is not a person?
Yes. Any two dates work, so a founding date or a completion date gives the age of a company or a building in the same format.
Is the date of birth stored?
No. It is used for the arithmetic in your browser tab and nothing else. It is not uploaded, not stored, and it is gone when you close the tab.
Which format to read
Enter the birthday and the date to measure to. Today is filled in for you, and any past or future date can replace it. The answer breaks down into years, months and days.
- Years, months and days is the format people use out loud, and it follows real month lengths.
- Total days and total weeks are easier to compare, which helps when planning around a date.
- Setting a future date shows the age on that day, so a birthday ahead can be checked directly.
Full specification
| What you enter | A birthday from the calendar picker, and the date to measure to. |
|---|---|
| What you get | Years, months and days, along with the same span given as total months and total days. |
| Date to measure to | Today by default, and any past or future date can be chosen instead. |
| Leap years | February 29 is handled by the Gregorian rule, and month lengths are used as they are. |
| How many at once | One birthday at a time. |
| Price | Free |
| Account required | No |
| Where it runs | In your browser tab. Nothing is sent anywhere. |
Keep going with the same files
All date tools: Date tools on SPOTTOOLS