Timestamp Converter
Convert between Unix timestamps, ISO 8601, and human-readable dates.
Runs 100% client-sideOn this page4 sections
Enter a timestamp or date to see all conversions.
HOW TO USE
- 01Paste a Unix timestamp (seconds or milliseconds), an ISO 8601 string, or any human-readable date.
- 02Format auto-detects — every conversion appears at once with copy buttons.
- 03Click Now to fill the current timestamp.
Try it
Unix seconds: 1735689600
ISO 8601: 2025-01-01T00:00:00Z
Date string: Jan 1 2025WHEN TO USE
Use this when you encounter a Unix timestamp, an ISO 8601 string, or a human-readable date in a log, API response, or database field and need to convert it to a readable form — or the reverse. Log timestamps are frequently in Unix seconds or milliseconds; API responses often use ISO 8601; database fields may use either. This tool converts all formats simultaneously so you see the equivalent in every form without knowing which you started with.
WHAT BUGS THIS FINDS
Unix milliseconds vs seconds confusion
A timestamp field of 1735689600000 (milliseconds) interpreted as seconds produces a date 1000x too far in the future — convert both values here to confirm which interpretation matches the expected date.
Timezone offset not applied
An API returns a UTC ISO 8601 timestamp but the application displays it without converting to local time — convert the timestamp here and compare UTC and local representations to confirm the offset is applied.
Date string format rejected by parser
A date string formatted as 'Jan 1 2025' is rejected by a strict ISO 8601 parser — convert it here to get the canonical 2025-01-01T00:00:00Z form the parser accepts.
DST boundary produces wrong hour
A timestamp falling exactly on a daylight-saving transition is converted to the wrong hour — convert the boundary timestamps to both UTC and local to confirm the transition is handled correctly.
QA USE CASES
Log timestamp decoding
Paste a Unix timestamp from a log line and confirm the human-readable date and time match the expected event window before correlating logs with test run timings.
API response date field validation
Convert the ISO 8601 timestamp returned by an API to confirm it represents the expected date and time in the correct timezone before asserting on it in a test.
Fixture date seeding
Convert a target date (e.g. 'Jan 1 2025') to Unix seconds or milliseconds to use as the value in a database fixture or API mock response timestamp field.