Unix timestamp converter

How to convert a Unix timestamp

1. Paste a Unix timestamp into the input field, using Timestamp → Date for seconds or Milliseconds for milliseconds.
2. The tool converts it to a human-readable date and time instantly.
3. Read the result in UTC, ISO 8601, your local time zone and as relative time.
4. Or enter a date and time to get the corresponding Unix timestamp.

Common uses

• Debugging API responses that contain Unix timestamps, use JWT decoder to inspect the exp and iat claims in auth tokens
• Converting timestamps in server logs to readable dates
• Getting the Unix timestamp for a specific date to use in a query or script. The date calculator is useful for adding or subtracting days from a date

For background on Unix time, ISO 8601 and daylight saving, read the complete guide to time tools.

Technical specification

• Algorithm or formula: Constructs a JavaScript Date from the timestamp via new Date(value) (milliseconds) or new Date(value * 1000) (seconds). Reverse direction uses date.getTime() divided by 1000 for seconds output.
• Browser API or library: Native Date and Intl.DateTimeFormat for locale-aware formatting; no external library.
• Input limits: Timestamp → Date reads the value as seconds and the Milliseconds mode reads it as milliseconds; a seconds value of 100,000,000,000 or more shows a warning that it looks like milliseconds. Range follows ECMAScript Date limits (±100,000,000 days from 1970-01-01).
• Output: UTC ISO string, local time formatted for your zone, and a human-readable relative time (e.g., "3 days ago"). Bidirectional: date-to-timestamp also supported.
• Known limitations: Leap seconds are not represented (matches JavaScript Date semantics). Sub-second precision beyond milliseconds is not modeled.

Frequently asked questions

What is a Unix timestamp?

A Unix timestamp is the number of seconds (or milliseconds) elapsed since 1 January 1970 00:00:00 UTC (the Unix epoch). It is a standard way to represent dates in programming.

How do I know if my timestamp is in seconds or milliseconds?

A 10-digit number is typically seconds (valid up to year 2286). A 13-digit number is milliseconds. Timestamp → Date reads the value as seconds and warns when it looks like milliseconds; switch to the Milliseconds mode for those.

Is my data sent to a server?

All conversions run in your browser. Our servers are not involved at any point.

Can I get the current timestamp?

Yes. The "Now" mode shows the current Unix timestamp, updating every second, and "Use now" fills the input with the current time. Useful for generating test values or setting expiry times.