Unix Timestamp Converter
Convert Unix timestamps (seconds or milliseconds) to UTC/local dates and back, with explicit timezone semantics.
Timestamp → Date
Date → Timestamp
The date and time above is interpreted in your browser’s local timezone — it is never silently reinterpreted as UTC or any other timezone.
No timezone database or external lookup is used — conversions rely only on your browser’s built-in date handling. Everything runs locally; nothing is sent anywhere.
Enter a Unix timestamp and choose whether it’s in seconds or milliseconds — the unit is never guessed. For example, 1700000000 seconds converts to 2023-11-14T22:13:20.000Z in UTC; the timestamp 0 is the Unix epoch, January 1, 1970 UTC.
For the reverse direction, the date and time you enter is read in your browser’s own local timezone — it is never silently reinterpreted as UTC. This tool doesn’t use a named timezone database, so it can’t convert to a specific city or region’s timezone — only UTC and your browser’s local time.
How to use the Unix Timestamp Converter
- In the Timestamp → Date panel, type or paste a number into the Unix timestamp field.
- Set Unit to Seconds or Milliseconds to match where the number came from.
- Read the UTC, Your local time, and ISO 8601 results, and use Copy on the one you need.
- To go the other way, pick a value in the Date and time field of the Date → Timestamp panel, or click Use current time.
- Copy the Unix seconds or Unix milliseconds result.
Example: Start of 2025
Enter 1735689600 with Unit set to Seconds. UTC shows Wed, 01 Jan 2025 00:00:00 GMT and ISO 8601 shows 2025-01-01T00:00:00.000Z. In a browser set to US Eastern time, Your local time shows Tue Dec 31 2024 19:00:00 GMT-0500 (Eastern Standard Time).
Questions about the Unix Timestamp Converter
- My date came out tens of thousands of years in the future. What went wrong?
- The number is almost certainly in milliseconds while Unit is set to Seconds. For example, 1735689600000 read as seconds gives the year 56971; switch Unit to Milliseconds to get 2025-01-01T00:00:00.000Z.
- Why does Date → Timestamp give a different number than I expected for midnight?
- The date you pick is read in your browser's local timezone, not UTC. Entering 2025-01-01 00:00 in US Eastern time gives 1735707600, which is five hours after 1735689600 (midnight UTC).
- Can I convert negative timestamps or dates before 1970?
- Yes. Negative values count backward from the epoch, so -86400 seconds converts to 1969-12-31T00:00:00.000Z. Values beyond what a JavaScript date can hold show the message that the timestamp is outside the representable range.
- Does Use current time include seconds?
- No. The date and time field works to the minute, so the resulting Unix seconds always fall on a whole minute and the milliseconds value ends in 000.