Unix Timestamp Converter
A Unix timestamp is the number of seconds (or milliseconds) since 00:00:00 UTC on 1 January 1970 — the Unix epoch. It's how most computer systems store a moment in time internally, independent of timezone or calendar format. This free converter runs a live epoch clock, turns a timestamp into a readable local/UTC/ISO date, and turns a date back into a timestamp — automatically detecting whether a pasted number is in seconds or milliseconds. Nothing is sent to a server; the conversion runs entirely in your browser.
About the Unix timestamp converter
A Unix timestamp counts seconds (or milliseconds) since 00:00:00 UTC on 1 January 1970. This converter shows a live epoch clock, converts any timestamp into a local/UTC/ISO date, and converts a date back into a timestamp — automatically detecting seconds versus milliseconds.
Computers need a way to store a moment in time that doesn't depend on timezone, calendar, or language — Unix time solves this by counting the number of seconds that have elapsed since a fixed reference point: midnight UTC on January 1, 1970, known as the Unix epoch. Almost every programming language and database can produce or consume this format, which is why timestamps show up constantly in logs, APIs, and databases. This tool provides a live-updating epoch clock plus two-way conversion: paste a timestamp to see it as a readable date in your local time, UTC, and ISO 8601 format, or enter a date to get its Unix timestamp in both seconds and milliseconds.
Recognizing timestamp formats
| Digits | Unit | Example |
|---|---|---|
| 10 digits | Seconds | 1735689600 |
| 13 digits | Milliseconds | 1735689600000 |
| 16 digits | Microseconds (rare) | 1735689600000000 |
When to use a Unix timestamp converter
- Debugging an API response or log file that shows a raw timestamp instead of a readable date.
- Converting a database `created_at` or `updated_at` field to check when a record was actually made.
- Setting up a scheduled task or cron-adjacent system that expects a Unix timestamp as input.
- Checking whether a JWT or session token's expiry timestamp has already passed.
- Quickly getting "right now" as a timestamp to paste into code or a test payload.
How to use the converter
- To convert a timestamp to a date: paste the number into the "Unix timestamp → date" field. The tool automatically detects seconds vs milliseconds by magnitude.
- Read the result in your local time, UTC, ISO 8601 format, or as a relative time ("3 days ago").
- To convert a date to a timestamp: pick a date and time in the "Date → Unix timestamp" field, or click "Use current time".
- Copy any result with one click — nothing is sent to a server, the whole conversion runs in your browser.
Tips
- If a timestamp looks like it converts to a date decades in the future or the 1970s, you likely have the seconds/milliseconds unit backwards — try the other one.
- ISO 8601 (e.g. 2026-01-01T00:00:00.000Z) is the most portable format to paste into most programming languages and APIs.
- The "current time" values update every second — refresh your copy if you need a truly current timestamp for a test.
Unix timestamp FAQ
What is a Unix timestamp?
The number of seconds (or milliseconds) since 00:00:00 UTC on 1 January 1970 — the "Unix epoch." It is a compact, timezone-independent way computers represent a moment in time.
How do I know if a number is in seconds or milliseconds?
A 10-digit number (like 1735689600) is typically seconds; a 13-digit number (like 1735689600000) is typically milliseconds. This tool detects that automatically based on magnitude.
What is the year 2038 problem?
Some older systems store Unix time as a 32-bit signed integer, which overflows on 19 January 2038. Modern systems using 64-bit integers are unaffected.
Does this tool work offline?
Yes — the conversion is pure JavaScript math running in your browser; no data is sent anywhere.