Online date and time calculators

Working out an exact age, a number of business days, or a fair meeting time across time zones is the kind of maths that's simple in theory and irritating in practice, mostly because public holidays and different month lengths keep getting in the way. This hub gathers eighteen date and time calculators built to handle that arithmetic properly, rather than approximately.

The age calculator gives your exact age in years, months and days from a birth date, along with the total number of days you've been alive, which turns out to be a more common request than it sounds. The date difference calculator does the same job between any two dates, useful for anything from project deadlines to working out how long ago something happened.

Calculators built around Australian conditions

• Working days calculator, which excludes weekends and the correct public holidays for your state
• Date difference calculator, for the exact gap between two dates in days, weeks or months
• Age calculator, down to the day
• Time zone converter, covering all three Australian zones and daylight saving automatically
• Meeting planner, for finding a workable time across several cities at once

The working days calculator is the one most tools get wrong, because "business days" in Australia depends on which state you're counting for — a date might be a working day in Perth and a public holiday in Melbourne on the same afternoon. This calculator lets you pick the state so the count actually matches your calendar.

The time zone converter and meeting planner exist for the same reason remote work made them necessary: finding a slot that isn't 6 am for someone and 11 pm for someone else. Both account for daylight saving automatically, including the fact that Australia's clocks shift on the opposite schedule to Europe and North America.