Developer / TOOLKIT
Unix Timestamp Converter
Convert between Unix timestamps and readable dates, in seconds or milliseconds.
Free to use · No account needed
How to use
- Timestamp → Date: paste a Unix timestamp into the left box and click Convert. Seconds (10 digits) and milliseconds (13 digits) are detected automatically.
- Date → Timestamp: pick a date and time on the right and click Convert to get both the second and millisecond values.
- Click Use current time to work with the present moment.
Unix timestamps count seconds since January 1, 1970. Convert between epoch time and human-readable dates to debug API logs, schedule cron jobs, or figure out when a session token expires. Supports both directions, timezone awareness and millisecond precision.
Use cases
1. Use case: Debug logs Convert a Unix timestamp from application logs into a readable date to correlate events.
2. Use case: Work with databases Translate between epoch milliseconds and human dates when reading API responses or DB columns.
Practical tips
The classic bug is seconds versus milliseconds: JavaScript's Date.now() returns milliseconds, while most backends and APIs use seconds — a ten-digit timestamp is seconds, a thirteen-digit one is milliseconds. Convert to a timezone explicitly; the tool shows UTC and your local zone side by side so a date rollover never surprises you. ISO 8601 output is the safest form to store, since it is unambiguous about order and timezone. Like every tool on this site, the Timestamp Converter runs entirely in your browser: the data you enter never leaves your device, nothing is uploaded to a server, and the tool keeps working if your connection drops.
Common mistakes
Timestamp bugs are almost always unit or timezone mistakes:
- Confusing seconds and milliseconds: a ten-digit timestamp is seconds, a thirteen-digit one is milliseconds — JavaScript's Date.now() returns milliseconds while most backend APIs use seconds.
- Reading a UTC result as local time (or the reverse) and concluding the data is wrong by several hours.
- Ignoring date rollover: an evening timestamp in one zone is often tomorrow morning in another.
- Storing local time instead of ISO 8601 in databases, which breaks the moment a server or user changes timezone.
Boundary and failure cases
Seconds versus milliseconds is the most common silent failure. A 13-digit value interpreted as seconds lands centuries in the future; a 10-digit value interpreted as milliseconds lands in 1970. Confirm digit length and one known fixture before batch-converting logs.
Time zones and DST shift wall-clock display without changing the underlying Unix instant. Local formatting uses this browser's zone. When systems disagree, compare UTC sides first, then apply each system's zone rules.
Leap seconds are not represented in plain Unix time the way civil clocks imply. Extremely distant dates may also hit Date precision limits in JavaScript. For legal or astronomical work, use a purpose-built library rather than a browser Date shortcut.
Frequently asked questions
Does the Timestamp Converter send my data anywhere?
No. Conversion runs in your browser from the values you enter. Nothing is uploaded by this tool.