What does the Timestamp do?
Unix time counts seconds (or milliseconds) since 1970-01-01T00:00:00Z. This converter maps that number to an ISO 8601 string and the other way around.
Unix Timestamp Converter
Convert Unix time to ISO dates and back, locally. Nothing is uploaded.
The Unix Timestamp Converter treats 10-digit values as seconds and 13-digit values as milliseconds — a rule that classifies every timestamp between 1970 and the year 33658 correctly — and outputs ISO 8601 in UTC.
- Unix seconds
- 1788173482
- ISO 8601 (UTC)
- 2026-08-31T10:51:22.000Z
How does the Timestamp work?
Numbers below 1e12 are treated as seconds; larger numbers as milliseconds. Date strings are parsed by the browser Date constructor and emitted as UTC ISO.
Does this upload my text?
No. This page never sends your input to a server — formatting, decoding and hashing all run in this tab, on this device.How that works.
Frequently asked questions
Seconds or milliseconds?
If the number has 13 digits it is almost certainly milliseconds. 10-digit values are seconds. The tool uses that heuristic.
Which timezone?
Output is always UTC (the Z suffix). Your local zone is not applied, which keeps logs comparable.
Why Use now?
It fills the current Unix seconds from your clock so you can compare an exp claim to wall time.
Is anything uploaded?
No.
Do one job
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