Unix Timestamp Converter
?About this tool, how to use it, and FAQ▾
What is a Unix timestamp converter?
A Unix timestamp counts seconds since January 1, 1970 UTC (the epoch). They are everywhere in logs, APIs, JWTs, and databases — and unreadable to humans. This converter takes a timestamp and returns the ISO 8601 form, a human-readable date, and the timezone, automatically detecting whether you pasted seconds or milliseconds.
It shows both epoch seconds and epoch milliseconds side by side, which catches the classic off-by-1000 bug when systems disagree about units.
How to use
- Paste a timestamp — 1751500800 (seconds) and 1751500800000 (milliseconds) are both detected automatically.
- Read the ISO 8601 and human-readable conversions.
- Use the seconds and milliseconds outputs to normalize values between systems that use different precision.
Frequently asked questions
How do I tell seconds from milliseconds?
Length. Current dates are 10 digits in seconds and 13 in milliseconds. A 13-digit value fed into a seconds-based API lands tens of thousands of years in the future — the converter detects the unit so you don't have to.
Are Unix timestamps affected by timezones?
No — a timestamp is an absolute moment, always relative to UTC. Timezones only appear when you format it into a date string, which is where mismatched renderings between systems come from.
What is the year 2038 problem?
Systems storing timestamps as signed 32-bit integers overflow on January 19, 2038. Modern 64-bit systems are unaffected, but embedded devices and old file formats can still carry the limitation.