Category
Date & Time
Five tools for date arithmetic that is easy to get subtly wrong. Convert a meeting time across zones with daylight saving applied, count the exact days between two dates, translate a Unix timestamp into a readable date, or run a timer.
All Date & Time tools5 tools
Where date arithmetic usually goes wrong
Two mistakes account for most wrong answers. The first is treating a year as 365 days, which drifts by a day for every leap year in the range, so an age or a long gap comes out short. The second is ignoring daylight saving, which makes a converted meeting time an hour off for part of the year, and off by a different amount depending on which hemisphere each participant is in. Timezone Converter uses the IANA time zone database, so it knows the actual transition dates for each region rather than applying a fixed offset. Date Difference and Age Calculator count real calendar units.
Timestamps and countdowns
Unix Timestamp Converter goes both ways and handles seconds and milliseconds, which is the usual source of a result that is off by a factor of a thousand or sitting in 1970. Days Until Calculator counts down to a launch, an exam, or a deadline. Timer & Stopwatch runs in the tab and keeps counting when the tab is in the background.
Frequently asked questions
Does the timezone converter account for daylight saving?
Yes. It uses the IANA time zone database, which records the exact transition dates for each region, so converting a time in July and the same time in January gives different offsets where that is correct.
Why does the age differ from another calculator by a day?
Because this one counts real calendar months and leap days rather than dividing the total by 365. Over a few decades that difference compounds into a day or two, and the calendar count is the one that matches how age is normally stated.
Are timestamps in seconds or milliseconds?
Both are accepted. Unix time is conventionally in seconds, while JavaScript uses milliseconds, and mixing them is what produces a date in 1970 or one tens of thousands of years away. The converter detects which you have pasted.