Web & encoding
Unix Timestamp Converter
Paste a Unix timestamp in seconds or milliseconds and get the ISO 8601 date, UTC and local time, plus a relative “3 days ago” reading. Paste a date and get the timestamp back.
- Runs 100% in your browser
- No signup · No uploads
- Free, unlimited use
Timestamp or date (or many lines)
Examples: Single timestamp · Multiple lines — ⌘/Ctrl + Enter converts · drop a file to load it · processed locally
Converted output
Output is read-only. Use Copy, Download or Share to move it out.
How to use the timestamp converter tool
-
Paste or type
Seconds, milliseconds or a date string like 2026-10-12T09:30:00Z. The unit is detected from magnitude.
-
Read every form at once
Output includes epoch seconds, epoch millis, ISO 8601 UTC, human UTC, local time and relative time.
-
Batch a log file
Paste one value per line to convert a whole column of timestamps into a table at once.
What makes this one different
- Seconds and milliseconds auto-detected by magnitude
- ISO 8601, UTC, local and relative output side by side
- Batch mode: one timestamp per line becomes a TSV table
- “now” works as input, with a live current-epoch display
- Handles negative (pre-1970) timestamps correctly
Privacy by architecture: this page contains no analytics that receive your input, and the conversion code runs in your tab. You can disconnect from the network after loading and keep working.
Timestamp Converter — frequently asked questions
How do I tell seconds from milliseconds?
By magnitude: epoch seconds are 10 digits today (1735689600), milliseconds 13 (1735689600000). The converter applies that rule, and also honours explicit decimals — 1735689600.5 is treated as seconds with a fractional part.
What is the difference between UTC and local output?
Both describe the same instant. UTC is timezone-independent — always safe for storage and logs. Local shows what your device’s clock displays, using the browser’s timezone, which is what a user perceives.
Why do my timestamps look off by hours?
Almost always a timezone bug rather than a timestamp bug: a value created with a local-time parser but read as UTC (or vice versa). Compare the UTC and local rows here — if they differ by your UTC offset, that is the cause.
Can I convert dates before 1970?
Yes. Negative Unix timestamps are valid and represent dates before the epoch; the converter handles them and also parses historical date strings.
What about Y2038?
The 32-bit signed integer overflow at 03:14:07 UTC on 19 January 2038 affects old systems storing timestamps as int32. In JavaScript, this tool is unaffected — and current practice of 64-bit or millisecond storage is not subject to it.
Related tools
Searching for “unix timestamp converter”, “epoch to date”, “timestamp to date online”? You are in the right place — browse all 19 tools.