Unix Timestamp Converter
Convert Unix epoch timestamps in seconds or milliseconds to a readable date, and back again.
Direction
Converted live as you type. Nothing leaves your browser.
Enter a timestamp to see the date.
How to convert a Unix timestamp
Choose the direction
Pick Timestamp to date or Date to timestamp. Both inputs start prefilled with the current moment.
Paste the value
Enter an epoch number. Seconds or milliseconds are detected from the digit count, and a toggle overrides the guess.
Read the conversions
The result shows local time, UTC, ISO 8601, and a relative phrase, updating as you type.
Copy the format you need
Click the copy button to take the ISO 8601 string, or the Unix seconds in the reverse direction.
Why use this tool
Automatic unit detection
Values with 13 or more digits are treated as milliseconds and shorter ones as seconds, with a manual toggle for edge cases.
Four formats per timestamp
Each conversion shows local time, UTC, an ISO 8601 string, and a relative phrase such as "2 hours ago".
Both directions
A second mode converts a local date and time back into epoch seconds and milliseconds.
Pre-1970 support
Negative timestamps are valid input, so dates before the Unix epoch convert like any other value.
Instant and local
Conversion happens on every keystroke using the browser Date and Intl APIs; no value you paste is transmitted.
About this tool
This Unix timestamp converter turns epoch time into a readable date and back, live as you type. Paste a number and it is shown as your local time, UTC, an ISO 8601 string, and a relative phrase such as "3 days ago". Whether the value is seconds or milliseconds is detected from its length, 13 or more digits reads as milliseconds, and a toggle forces either unit when the guess is wrong. Negative values are accepted too, so instants before 1 January 1970 convert normally. The reverse mode takes a date and time in your local zone and returns both epoch seconds and milliseconds.
Epoch values show up wherever machine time is stored: log lines, database columns, API responses, cache expiry headers, and the iat and exp claims inside JSON Web Tokens, which you can inspect with the JWT decoder. Debugging usually starts with a bare number and the question of when that actually was, and the relative readout answers it at a glance without any mental arithmetic.
Conversions use the Date and Intl APIs built into the browser, so no timestamp you paste leaves the tab. To view one moment across several cities rather than just local and UTC, hand the value to the time zone converter, and when the timestamp comes from a scheduled job, the cron parser shows when that schedule fires next.
Frequently asked questions
- What is a Unix timestamp?
- A Unix timestamp is the number of seconds (or milliseconds) that have elapsed since 00:00:00 UTC on 1 January 1970, known as the Unix epoch. It is a compact, time-zone-free way to store an exact instant, which is why databases, logs, and APIs use it constantly.
- How does it tell seconds apart from milliseconds?
- By default the converter auto-detects the unit from the length of the number: 10-digit values are read as seconds and 13-digit values as milliseconds. You can override this with the unit toggle if your timestamp falls outside the usual range.
- Which time zones does the output show?
- Every conversion shows your local time (using your browser time zone), UTC, and an ISO 8601 string, plus a relative description like "2 hours ago" so you can sanity-check the value at a glance.
- Is my data uploaded anywhere?
- No. Every conversion happens locally in your browser using the built-in Date and Intl APIs. Nothing you type is sent to a server, stored, or logged.
- Can I convert a date back into a timestamp?
- Yes. Switch to the "Date to timestamp" mode, pick a date and time, and the tool gives you both the seconds and milliseconds epoch values ready to copy.
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