Last reviewed: 2026 · Updated for 2026
Epoch & Unix Timestamp Converter Guide: Dates Explained (2026)
Logs, APIs, databases and tokens rarely store dates as words — they store a plain number called a Unix timestamp. Once you understand what that number means, reading machine timestamps becomes second nature. This guide explains Unix time and shows you how to convert it both ways with a free online epoch converter.
What a Unix timestamp is
A Unix timestamp is simply the number of seconds that have passed since the epoch — midnight UTC on 1 January 1970. So 1751328000 is not random; it is an exact point in time. Storing time as a single integer is brilliant for computers: it is easy to compare, sort and do arithmetic on, and it has no ambiguity about format. The trade-off is that it is meaningless to humans until you convert it.
Seconds vs milliseconds
The most common confusion is scale. Back-end systems, databases and standards like JWT expiry usually store seconds — a 10-digit number today. Browsers and JavaScript typically use milliseconds — a 13-digit number. Mix them up and your date lands in 1970 or thousands of years in the future. When a converted date looks absurd, the culprit is almost always a seconds/milliseconds mismatch.
UTC and time zones
A Unix timestamp is always measured in UTC — it has no time zone baked in. The time zone only matters when you display the value to a person. That is a feature, not a bug: store everything in UTC, and convert to the viewer's local time only at the last moment. If you need to see the same instant across cities, our Timezone Converter handles the local display side.
How to convert a timestamp, step by step
- Open the Epoch Converter.
- Paste your number and confirm whether it is in seconds or milliseconds.
- Read the human-readable UTC and local date it produces.
- Or go the other way — enter a date to get the timestamp for a config, query or test.
Where you will meet timestamps
Unix time is everywhere once you start looking. Server logs stamp every line with it. JWT tokens use it for the issued-at and expiry claims — if you are decoding one, our JWT Decoder pairs perfectly with this converter. Databases store created-at columns as timestamps, cache systems use them for expiry, and rate limiters use them to measure windows. Being fluent in reading these numbers turns opaque logs into a clear timeline.
The 2038 problem in one paragraph
Older systems stored Unix time in a signed 32-bit integer, which can only count up to just past 03:14 UTC on 19 January 2038 before it overflows into a negative number. Any long-lived system still using 32-bit time needs to move to 64-bit storage, which extends the range so far it is effectively unlimited. If you maintain legacy code, it is worth checking now rather than in 2037.
Frequently asked questions
Is the converter free? Yes — no sign-up, and it runs entirely in your browser.
Why is my date showing 1970? You almost certainly passed milliseconds as seconds, or the value was zero. Check the digit count.
Does it handle negative timestamps? Yes — negative values represent dates before 1970.