All calculators

Ten free tools for working with dates and ages. Every one runs entirely in your browser, needs no sign-up, and gives an answer as you type.

Age Calculator
Your exact age in years, months and days, plus weeks, hours, minutes and a live seconds counter.
Most popular
Date Difference
Days, weeks and working days between any two dates, with inclusive and exclusive counting.
Birthday Countdown
A live countdown to your next birthday, down to the second, and the weekday it lands on.
Age Difference
The exact gap between two people, and why the stated gap in years shifts during the year.
Chronological Age
Years;months notation for educational and clinical assessment, computed to the test date.
For professionals
Day of the Week
What day any date fell on, and when your birthday next lands on each day of the week.
Zodiac Sign
Your star sign with element, quality and ruling planet, plus your Chinese zodiac animal.
Leap Year Checker
Whether any year is a leap year, the next and previous ones, and leap days in a range.
Business Days
Add or subtract working days, or count them between two dates. For deadlines and notice periods.
Pet Age
Dog and cat age in human years using the size-adjusted veterinary method, not the myth.

Which one do you need?

For an age — the age calculator covers almost everything, including your age on a past or future date. Use the chronological age calculator instead if you need the years;months form for an assessment report, and the age difference calculator to compare two people.

For a span of time — the date difference calculator counts days and weeks, and the business days calculator handles anything where weekends should not count, such as notice periods and delivery windows.

For something about a specific date — the day of the week calculator tells you which day it fell on, the leap year checker settles whether a year has a 29 February, and the zodiac sign calculator covers star signs and birthstones.

For fun — the birthday countdown ticks down to the second, and the pet age calculator converts your dog or cat's age properly rather than multiplying by seven.

What every calculator here has in common

  • Nothing is sent to us. All arithmetic runs in your browser. Your dates never reach a server.
  • Real calendar days are counted. No year is approximated as 365 or 365.25 days, so leap days and century exceptions are always handled correctly.
  • Daylight saving cannot shift the answer. Dates are anchored at midday, leaving twelve hours of margin against any clock change.
  • The conventions are documented. Where more than one answer is defensible — as with month-end dates — we say which we use and why.

More on the reasoning behind all of this is in our editorial standards and in the guide to how age is calculated.