Online date and time calculators

Free calculators that work everything out in your browser — choose a tool below.

Age and birthday

Exact age, next birthday, half birthday and star sign — all from one date of birth.

Age calculation Next birthday Half birthday Star sign Chinese sign

Days between two dates

How many days until a date and since a date, working days with public holidays taken into account, and the full difference between two dates.

Days until a date Days since a date Working days Date difference

Hours and duration

Hours and minutes between two times, and the exact length between two dates.

Hours between two times Duration

Adding and subtracting dates

What date it will be in X days, weeks, months or years — and what date it was X ago.

Add days Subtract days Add weeks Add months Add years

Time zones

Convert the time between cities around the world and plan meetings across several time zones.

Time zone converter Meeting planner

World clock — live clocks

Date arithmetic is simple to describe and tedious to do. Months are different lengths, February moves, weekends interrupt everything, and in the Emirates half the public holidays are not fixed to the Gregorian calendar at all. The eighteen calculators gathered here take that work off your hands and give an answer you can act on.

The working days calculator carries the local complication. The working week runs Monday to Friday with Saturday and Sunday off, which is straightforward until a lunar holiday lands in the middle of the count, or until you remember that the emirate of Sharjah keeps a shorter week than its neighbours. Counting ten working days from a Sunday in a month containing Eid can land on three different dates depending on which announcement you were counting from and which emirate the office sits in.

What is in the set

Age to the exact day, and the total number of days lived
Date difference, working days, and days until or since a given date
Adding or subtracting days, weeks, months and years with sensible month-end handling
Hours between two times, including ranges that cross midnight
A time zone converter and a meeting planner built around Gulf Standard Time

The time zone tools are the ones that get the heaviest use in a country where most people work across at least one border. Because the Emirates never change their clocks, every shift in a standing meeting comes from the other end: a call with London slips by an hour at the end of March and again at the end of October, a call with New York slips on different weekends entirely, and for a couple of weeks in spring the two are out of step with each other as well. The converter applies the rules in force on the date you ask about rather than assuming a remembered difference.

Every calculation runs in the browser on your own device. Nothing you type is transmitted, stored on a server, or attached to you in any way.

Common questions

Which days count as working days?

Monday to Friday, with Saturday and Sunday excluded, plus the public holidays announced for the year. Friday counts as a working day even though it is a short one for many employers.

Can I get my age in years, months and days?

Yes. The age calculator breaks it down to the day and also gives a running total of days lived, which is usually a larger number than people expect.

Does the hours-between calculator handle a shift that crosses midnight?

Yes. If the finish is earlier than the start it treats the finish as falling the next day, so a 10 pm to 6 am shift comes out as eight hours rather than something negative.

What happens when I add a month to 31 January?

You get the last day of February — the 28th, or the 29th in a leap year — rather than a date that does not exist. The same rule applies wherever the target month is shorter.

Does the time zone converter handle countries that change their clocks?

Yes. Gulf Standard Time is constant, so the converter applies the other country's rules for the date you ask about, which is where every seasonal shift actually comes from.