Unix Timestamp Converter
Calculators & Converters
Convert Unix timestamps to human-readable dates and back. Supports seconds and milliseconds, with simultaneous local time, UTC, and ISO 8601 readouts.
Runs entirely in your browserAbout Unix Timestamp Converter
Unix timestamps — the number of seconds (or milliseconds) since January 1, 1970 UTC — are the backbone of how computers store time. Databases use them, log files use them, APIs use them, JWTs use them. But the number itself is opaque ('what does 1716250799 mean?'), so converting back and forth between timestamps and human dates is a frequent chore.
This converter does both directions. Paste a timestamp to get the local time, UTC, ISO 8601 string, and the equivalent value in the other unit (seconds ↔ milliseconds). Or paste a local date+time to compute the Unix timestamp. The seconds/milliseconds toggle matters — JavaScript's `Date.now()` returns milliseconds, but databases like PostgreSQL and conventions like JWT `exp` claims use seconds. Getting this right avoids a 1000× error. Everything runs in your browser.
How to use
- 1
Pick a direction
Use the tabs: 'Timestamp → Date' or 'Date → Timestamp'.
- 2
Pick the unit
Seconds (used by JWT, PostgreSQL, Unix shell tools) or Milliseconds (used by JavaScript Date.now and most JSON APIs).
- 3
Enter the input
For timestamp → date: type the integer timestamp. For date → timestamp: pick a local date and time.
- 4
Read the conversions
All four common forms are shown: local time, UTC, ISO 8601, and the value in the other unit.
- 5
Use Now
Click Now to fill the current moment.
Examples
Decoding a JWT exp claim
JWT exp is seconds since epoch. A claim of 1716250799 decodes to May 20, 2024, 4:13 PM UTC.
Input
1716250799Output
UTC: Mon, 20 May 2024 16:13:19 GMT · ISO: 2024-05-20T16:13:19.000ZDate.now() value in milliseconds
JavaScript's millisecond timestamps decode to the same moment but the unit toggle matters.
Input
1716250799000Output
Same moment — May 20, 2024, 4:13 PM UTCFrequently asked questions
Why do timestamps sometimes have 13 digits instead of 10?+
Ten-digit timestamps are seconds since epoch (Unix convention). Thirteen-digit timestamps are milliseconds since epoch (JavaScript/JSON convention). The unit toggle in this tool switches between them.
What's special about January 1, 1970?+
That's the Unix epoch — the arbitrary zero point Unix chose. It was the start of the year the team was working on Unix and they needed a fixed reference. Every Unix timestamp is offset from that moment.
Will Unix timestamps overflow in 2038?+
32-bit signed integer timestamps roll over on Jan 19, 2038 (the famous 'Year 2038 problem'). Most modern systems use 64-bit integers, which won't overflow for billions of years. This tool uses JavaScript's full 64-bit math.
Why does local time differ from UTC?+
Unix timestamps are always UTC. The 'local time' display converts to your time zone using the browser's current offset (DST-aware). Two viewers in different time zones see different 'local times' for the same timestamp.
Is my data uploaded?+
No. All conversions happen in your browser using the native Date object.
Related tools
Unit Converter
Convert units across length, mass, temperature, area, volume, speed, and more.
Age Calculator
Calculate exact age in years, months, and days from any birth date.
EMI Calculator
Estimate monthly loan EMI with a full amortization schedule and interest breakdown.
Percentage Calculator
Run quick percentage math: X% of Y, % change between values, add/subtract percentages.
File Size Converter
Convert between bytes, KB, MB, GB, and TB in binary or decimal units.
Time Zone Converter
Convert times across world time zones with DST-aware calculations.