Date and Time Calculators

Age, Days Between Dates, Working Days and Time Zone Converter

Calendar arithmetic is harder than it looks. Months are different lengths, leap years move things by a day, and a "working day" depends on where you are and which holidays count. These tools count the actual days instead of approximating, and convert between time zones without the off-by-one-hour mistakes.

Every Dates & Time tool

Age Calculator

Exact years, months and days from any date of birth.

Australia Working Days Calculator

Business days between two Australian dates, with state public holidays removed.

Time Zone Converter

Convert a date and time between any two cities.

Working Days Calculator

Business days between two dates, weekends and holidays excluded.

Why counting beats estimating

The average month is about 30.44 days, and dividing by that gives an answer that is usually close and occasionally wrong. Someone born on 31 January is not "one month old" on 3 March. The age and date-difference calculators step through the calendar — years, then months, then days — so the result matches what you would get counting on a wall calendar, and they show the total in days and weeks alongside so both readings are available.

Age

The age calculator gives years, months and days as of today or any date you choose, which covers the two common needs: how old someone is now, and how old they were or will be on a specific date. Leap-day birthdays are handled the way most jurisdictions handle them, with the birthday falling on 1 March in non-leap years, and the page says so.

Working days

Working days between two dates excludes weekends and, optionally, a list of public holidays you supply. The working week itself is configurable, because Friday-Saturday and Sunday-only weekends both exist. The result is useful for delivery estimates, notice periods and contractual deadlines, and the page shows which specific days were excluded so the count can be checked.

Time zones

The time zone converter uses the browser's own zone database, which is kept current by your operating system, so daylight-saving transitions are correct for the date you enter rather than for today. Converting a meeting time across three zones is a matter of adding each zone to the list; the tool also shows the UTC offset in effect on that date, which is what most scheduling mistakes come down to.

Nothing is sent anywhere

Dates of birth and travel plans are personal. All of these calculations happen in your browser; nothing you enter is transmitted or stored, and the pages keep working without a connection once loaded.