Time and Time Zone Tools
Time Tools cover the two conversions developers make most often: turning a Unix timestamp from a log, a database row or a JWT claim into a readable date, and working out what time a meeting, deploy window or incident falls at in other cities. Developers, SREs and distributed teams use them every day.
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All Time Tools (2)
Which tool do I need?
Read a timestamp from a log or a JWT as a date
Paste the number into the Epoch Converter. It detects the unit and shows UTC, local time and how long ago that was.
Find a meeting time that works in New York, London and Bangalore
Set the time in one zone in the Time Zone Converter, add the other cities, and share the link so everyone sees the same comparison.
Get the current Unix time for a test or API call
Use the Now button in the Epoch Converter; it follows the unit of the timestamp you last typed.
Check how daylight saving shifts a recurring call
Enter a date before and after the clock change in the Time Zone Converter. The US and Europe change on different weekends, so the gap shifts for a week or two.
About Time Tools
The Epoch Converter detects whether a number is in seconds, milliseconds or nanoseconds and shows it in UTC, in your local zone, as a relative time and in any extra zones you pick. The Time Zone Converter starts from a wall-clock time in one IANA zone, such as America/New_York, and shows the same instant in every zone you add, with the offset in force on that date. Both use the time zone database built into your browser, so daylight saving changes and past or future dates follow the same rules as your operating system. A common chain is to read an incident's timestamp in the Epoch Converter, then share the moment with colleagues in other zones through the Time Zone Converter's link.
A few rules prevent most time bugs. Store instants in UTC or with an explicit offset, and convert only for display. Use IANA zone names rather than abbreviations like CST, which mean different things in different places. Expect local times that do not exist, or happen twice, on daylight saving nights. And check the unit: a seconds value read as milliseconds lands in January 1970. Both tools run in the browser with no time server, so now means your device's clock, and nanosecond timestamps are truncated to milliseconds.
Guides
- Master Unix Epoch Time Conversion: Complete Developer Guide to Timestamp ProcessingMaster Unix epoch time conversion with our comprehensive guide. Learn timestamp formats, conversion techniques, and best practices for handling time data in software development.
- Time Zones for Developers: Offsets, DST and IANA Zone NamesA UTC offset is not a time zone. How the IANA database works, what happens to 02:30 on a DST night, and the rules that keep scheduling code out of trouble.
- Date Math for Developers: Month Ends, DST Days and Unix TimeCounting days between dates, adding months without landing in March, surviving 23-hour days and reading Unix timestamps in the right unit.
Frequently asked questions
Should I store dates as Unix timestamps or ISO 8601 strings?
Either works for an instant as long as the zone is unambiguous. Unix timestamps are compact and easy to compare, while ISO 8601 strings with an offset, such as 2026-03-02T14:30:00Z, are readable in logs and APIs. Future local events such as a 9:00 meeting in Berlin should store the local time and the IANA zone instead, because offsets can change.
Why do my converted times come out an hour off?
Usually daylight saving or the wrong zone. A fixed offset such as UTC+1 ignores summer time, a time stored without a zone gets read as local time, and the US and Europe change clocks on different dates. Converting with IANA zone names on the actual date avoids all three.
What is the difference between a time zone and a UTC offset?
An offset is a fixed difference from UTC at one moment, such as -05:00. A time zone, such as America/New_York, is a set of rules that says which offset applies on which date, including daylight saving and historical changes. One zone can have several offsets over a year.
Why are time zone abbreviations like IST or CST unreliable?
The same letters are used for different zones. CST can mean US Central Standard Time or China Standard Time, and IST is used for India, Ireland and Israel. Software can only guess which one you meant, so use IANA names such as Asia/Kolkata or America/Chicago.
Which clock do the time tools use for the current time?
Your device's clock. Neither tool calls a time server, so if your computer's clock is wrong, the Now value and relative times are wrong by the same amount. Time zone rules come from your browser's built-in database.