Date and time tools
Count the days between dates, add or subtract time, convert time zones and Unix timestamps, and find week numbers, business days and leap years.
- Time
Unix timestamp converter
Convert Unix seconds or milliseconds to a UTC date and time, or a date or ISO instant with an explicit offset to Unix time.
Open tool - Time
Date difference calculator
Count the days between two dates, with weeks, months, weekdays and hours. Uses the Gregorian calendar, so daylight saving changes do not affect the count.
Open tool - Time
Add or subtract dates
Add or subtract days, weeks, months or years from a date. When a month is shorter, the result moves to its last day, so January 31 plus one month is February 28 or 29.
Open tool - Time
ISO date validator
Validate a real YYYY-MM-DD date or a full ISO instant with seconds and an explicit Z or offset. Reject impossible dates, missing offsets and leap seconds.
Open tool - Time
Time zone converter
Convert a date and time from one time zone to another, with daylight saving applied by your browser for that date. Shows the time difference and other major cities.
Open tool - Time
Duration calculator
Add up to 100 durations, or subtract later durations from the first. Hours can exceed 24 and seconds can have up to three decimals.
Open tool - Time
Business day calculator
Move forward or backward by Monday to Friday days from a date. Skips weekends only, not public holidays or company closures.
Open tool - Time
ISO week number calculator
Find the ISO week number and week-year for a date. Weeks start on Monday and week 1 contains January 4, so dates near New Year can belong to the next or previous year.
Open tool - Time
Leap year checker
Check whether a Gregorian calendar year is a leap year. Years divisible by 4 are leap years, except century years unless they are also divisible by 400.
Open tool