How it works
Seconds are converted to milliseconds by multiplying by 1,000, then formatted with the browser date API. UTC and ISO 8601 output ignore the local zone; the local row applies the browser time zone for that instant, including daylight saving.
- Timestamps are interpreted as seconds unless the value is 11 digits or more, which is treated as milliseconds.
Why it matters
Timestamps appear in logs, tokens, databases and APIs, and half the confusion around them is unit confusion: milliseconds look like a date far in the future when treated as seconds. The other half is time zone confusion when a "wrong" date is actually correct in UTC.
A worked example
1793308626 seconds is 2026-10-29T21:17:06Z. The same instant is 2026-10-30 in Karachi and 2026-10-29 in Los Angeles, which is why UTC and local rows disagree.
Common mistakes
- Passing seconds to an API that expects milliseconds.
- Reading a UTC value as if it were local time.
- Assuming 10-digit values will keep working after 2038.
Practical tips
Store timestamps in UTC and format only at the edges. If a value looks like the year 55000, it is almost certainly milliseconds interpreted as seconds — divide by 1,000 before debugging anything else.
How to use it
- Open the tool. Everything runs in your browser tab.
- Paste or type your input, then choose the action you need.
- Check the result and copy it with one click.
Common questions
Does it read seconds or milliseconds?
Values with 11 or more digits are treated as milliseconds; shorter values as seconds. The page states which it used.
Is the Unix epoch supported?
Yes. A timestamp of 0 resolves to 1 January 1970, 00:00 UTC.
Why is local time different from UTC?
Local output uses your browser time zone, including daylight saving rules for that date.
Is this tool really free?
Yes. There is no account, no paywall and no usage limit. Tools App is funded by aumenso, the studio behind it.
Is anything I enter uploaded?
No. The tool runs in your browser tab; what you enter is never sent to us and never stored.