About this tool
APIs, logs and databases disagree about time: one returns Unix seconds, another milliseconds, a tracing system nanoseconds, and a fourth an ISO string with an offset. Mixing them up produces dates in 1970 or the year 50,000. This converter auto-detects the unit from the number’s magnitude (you can override it), then shows the same instant as Unix seconds and milliseconds, ISO 8601 in UTC, your zone and any other zone, the HTTP date format, and how long ago or from now it is. Paste a date string to go the other way. Time-zone offsets come from your browser’s Intl database, so daylight saving is applied correctly for each date.
How to use it
- Paste a timestamp or date string, or click “Use now”.
- Leave the unit on auto-detect, or force seconds, milliseconds, microseconds or nanoseconds.
- Pick an extra time zone to compare, such as where your servers or users are.
- Copy any of the converted values for assertions, test data or bug reports.
Unix Timestamp Converter FAQ
How does auto-detection tell seconds from milliseconds?
By magnitude. Second values stay below 100 billion until the year 5138, while millisecond values passed that in 1973. The same rule separates microseconds and nanoseconds. Force the unit if you work with dates far from the present.
Why is my ISO date off by a few hours?
A date-time without an offset or Z is interpreted in local time by JavaScript, while a date-only string like 2026-11-09 is treated as UTC midnight. Always include an offset in API payloads and test data.
Do Unix timestamps include leap seconds?
No. Unix time counts every day as exactly 86,400 seconds, so leap seconds are not represented. This rarely matters for application testing.