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Time & Date

Date and time calculators — age, durations, business days, time zones, and more.

11 tools

Time Zone Converter

Convert a time between any two time zones.

Date Calculator

Days between dates, or add/subtract days.

Age Calculator

Exact age in years, months, and days.

Stopwatch & Timer

Stopwatch with laps and a countdown timer.

Business Days Calculator

Count working days (weekdays) between two dates.

Unix Timestamp Converter

Convert between Unix epoch time and a human date.

Week Number Calculator

Find the ISO week number for any date.

Days Until Date

Count down the days until any future date.

Time Duration Calculator

Add, subtract, or find the duration between two times.

Hours Calculator

Hours worked from a start and end time, minus breaks.

Leap Year Checker

Check if a year is a leap year and why.

About time & date tools

The everyday arithmetic of dates and clocks — how long between two dates, your exact age, working days, week numbers, time-zone offsets, and Unix timestamps. Each tool is deterministic and shows how the number is worked out.

When to use these tools

Common time & date tasks and the tool that handles each one.

Frequently asked questions

Common questions about time & date — the concepts behind the tools above.

How do you count the number of days between two dates?
Subtract the earlier date from the later one; the result is the number of nights, or full days, between them. Whether you count both endpoints depends on your purpose — a hotel stay counts nights, but “how many days including today” adds one to the difference.
What are business days and how are they counted?
Business days are the working days between two dates, normally Monday through Friday with weekends excluded. Public holidays are also skipped, but which ones apply depends on your country or region, so counts can differ even for the same date range.
What are time zones and UTC offsets?
Coordinated Universal Time (UTC) is the global reference, and each time zone is expressed as an offset from it — New York is UTC−5 in winter, and India is UTC+5:30. Some places shift their offset for daylight saving time, so the difference between two cities can change during the year.
What makes a year a leap year?
In the Gregorian calendar a year is a leap year if it is divisible by 4, except century years, which must also be divisible by 400. So 2000 was a leap year but 1900 was not, and the extra day, 29 February, keeps the calendar aligned with the Earth’s orbit.

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