Developer · free
Timestamp Converter
Convert Unix timestamps in seconds or milliseconds to readable dates and back, in your local timezone or UTC, with ISO output.
Now (seconds)
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Now (millis)
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About the Timestamp Converter
Convert Unix timestamps in seconds or milliseconds to readable dates and back, in your local timezone or UTC, with ISO output.
All conversion is done locally in your browser.
How to use the Timestamp Converter
- Step 1Autodetect: a 10-digit timestamp is seconds, 13 digits is milliseconds.
- Step 2Type a timestamp to get the date — or pick a date to get timestamps.
- Step 3Toggle UTC and press Convert to switch timezone display.
When people reach for this tool
Turn a bare number into a date you recognise
Logs and APIs report Unix time with no context; converting it makes the entry readable.
Compare the same moment in UTC and locally
Seeing both readings side by side is usually the fastest way to find an offset error.
Produce the exact format an endpoint expects
Most APIs want ISO 8601 in UTC, which is awkward to type by hand.
Practical tips
- Timestamps come in seconds or milliseconds and the two look almost identical. The tool works out which from the length of the number.
- A Unix timestamp counts from 1 January 1970 UTC, so it carries no timezone of its own — the local reading is added for comparison only.
What you get
- Seconds and milliseconds autodetection
- Both directions: timestamp → date and date → timestamp
- Local and UTC output
- ISO 8601 formatting included
Timestamp Converter — FAQ
10 digits or 13?
10-digit timestamps are in seconds, 13-digit ones in milliseconds. The tool detects this automatically, and you can overrule it by adding or removing trailing zeroes.
What is a Unix timestamp?
It is the number of seconds (or milliseconds) that have passed since 1 January 1970 00:00:00 UTC — the universal clock used by APIs and databases.
Are timestamps in seconds or milliseconds?
Milliseconds are a thirteen-digit number and seconds are ten, which is usually enough to tell them apart. The converter checks the length and shows which it assumed.
Why does my local time differ from UTC?
The stored value is always UTC. The local reading simply applies your device timezone offset, so the two differ by that offset and nothing else.
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