A Unix timestamp is the number of seconds that have elapsed since midnight UTC on January 1, 1970, known as the epoch. It is the lingua franca of computers for representing a moment in time, but it is unreadable to humans. The ToolOrbit Unix Timestamp Converter translates between epoch numbers and clear dates in local, UTC, and ISO formats.
Seconds versus milliseconds
This is the most common source of confusion. Many systems, including most Unix tools and databases, use seconds. JavaScript's Date.now() and many APIs use milliseconds, which are 1000 times larger. A ten-digit number is almost certainly seconds; a thirteen-digit number is milliseconds. The converter auto-detects the unit so you do not have to guess.
1719619200 (seconds) -> 2024-06-29 00:00:00 UTC 1719619200000 (milliseconds) -> same instant ISO 8601: 2024-06-29T00:00:00Z
Time zones and formats
- Local: the date as it appears in your own time zone, including daylight saving
- UTC: the universal reference with no offset, ideal for logs and storage
- ISO 8601: the standard machine-readable string with a Z or numeric offset
- Always store and transmit timestamps in UTC, and convert to local only for display
Using the converter
Paste a timestamp to see it expanded into every format at once, or enter a human date to get the epoch value back. There is a one-click option to grab the current timestamp, handy for testing or seeding data. Everything is computed in your browser, so nothing you paste is sent anywhere.
Best practices
Be explicit about units in your APIs and database columns to avoid the seconds-versus-milliseconds trap. Keep timestamps in UTC end to end, and reserve local formatting for the final moment a value reaches a person. Watch for the year 2038 limit on 32-bit signed timestamps in older systems.
Timestamps you should recognize on sight
| Timestamp | UTC time | Vibe |
|---|---|---|
| 1609459200 | 2021-01-01 00:00:00 | New year |
| 1672531200 | 2023-01-01 00:00:00 | Monotonic SaaS debut |
| 1735689600 | 2025-01-01 00:00:00 | Recent |
| 1752537600000 | 2025-07-15 00:00:00 (ms) | Thirteen-digit surprise |
If a date imports as 1970 or as years earlier than expected, the two usual suspects are milliseconds (thirteen digits) where seconds (ten) were expected, and seconds treated as milliseconds. Anchoring on a few recent Januaries makes both errors visible in a glance. And plan ahead: 32-bit epoch time wraps in 2038 (the “Year 2038 problem”) for systems still storing it as 32-bit integers.
