How does it know if my input is seconds or milliseconds?
It checks whether the input is exactly 10 digits long — treating that as seconds, and anything else as milliseconds.
Developer Tools
Convert a Unix Timestamp to a Readable Date
Convert a Unix timestamp into ISO format, seconds, and milliseconds, right in your browser.
How seconds vs milliseconds gets detected
Enter a Unix timestamp and this tool converts it to an ISO date string, along with the equivalent Unix seconds and milliseconds values. To decide whether your input is seconds or milliseconds, it checks whether the typed string is exactly 10 characters long — a 10-digit number is treated as seconds and multiplied by 1000, anything else is treated as milliseconds directly.
That length-based detection works correctly for the vast majority of real-world timestamps (current Unix seconds are 10 digits until the year 2286), but a 9-digit or 11-digit numeric value — an old or unusually formatted timestamp — would be misread by this rule. If your result's date looks obviously wrong, that length-based guess is the first thing to double-check.
Workflow at a glance
Use this quick flow to understand where the tool fits in your work and what to review before relying on the output.
Review checklist
Before
Count the digits in your timestamp if you're unsure whether it's in seconds or milliseconds.
After
Confirm the resulting date looks reasonable — an obviously wrong year usually means the unit was misread.
When you need to read a raw timestamp
Use it to quickly turn a raw Unix timestamp — found in a log, a database record, or an API response — into a human-readable date, or to go the other direction and get a timestamp for a specific moment.
Who converts timestamps regularly
Backend developers
Convert a raw timestamp from a log or database record into a readable date.
Support engineers
Decode a timestamp mentioned in a bug report to understand when an event occurred.
QA testers
Generate or check timestamp values while preparing test data.
Anyone comparing logs across systems
Convert timestamps from different systems into one common readable format.
What this converter shows
ISO date output
Converts the timestamp into a standard ISO 8601 date string.
Seconds and milliseconds shown
Displays both Unix seconds and Unix milliseconds equivalents together.
Automatic seconds/milliseconds detection
Guesses the input's unit based on whether it's exactly 10 digits long.
Instant conversion
Output updates as you type or paste a value.
Converting a timestamp step by step
- 1Enter a Unix timestamp, in either seconds or milliseconds.
- 2Read the converted ISO date, Unix seconds, and Unix milliseconds values.
- 3Double-check the resulting date looks correct, especially for unusually short or long numeric input.
- 4Copy whichever value you need.
Where timestamp conversion helps
Converting a raw timestamp from a log or database record into a readable date.
Decoding a timestamp mentioned in a bug report to understand when an event occurred.
Generating or checking timestamp values while preparing test data.
Converting timestamps from different systems into one common readable format.
Where your timestamp goes
The conversion happens directly in your browser as you type — nothing you enter is sent to a server.
Avoiding a misread timestamp
- If the converted date looks obviously wrong, check whether your input was actually 9 or 11 digits rather than the expected 10 for seconds.
- When in doubt about the unit, count the digits yourself before trusting the automatic detection on an edge case.
- Use this in both directions — paste a timestamp to get a date, or a date string to get a timestamp.
- Cross-check an important conversion against a second source if the exact time genuinely matters.
Timestamp conversion mistakes to avoid
Trusting the length-based detection blindly on edge cases
A 9-digit or 11-digit numeric timestamp will be misread, since the detection specifically checks for exactly 10 digits.
Not verifying the resulting date looks reasonable
A misread timestamp often produces an obviously wrong date (like the 1970s or a far-future year) — check for that.
Mixing up seconds and milliseconds manually
Let the tool's detection handle typical 10-digit and 13-digit values rather than guessing yourself.
Assuming this checks timezone context
The ISO output reflects UTC-based conversion, not a specific local timezone display.
Double-checking an edge-case timestamp
Timestamp Converter handles the vast majority of real-world Unix timestamps correctly with its length-based unit detection. For unusual edge-case timestamps, a quick sanity check on the resulting date is worth the extra second.
Need hands-on help?
Get help with documents, SEO, content, or website fixes
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FAQ
Timestamp Converter FAQ
Answers for using Timestamp Converter on I Love Tool XYZ.
What if my timestamp is 9 or 11 digits?
It may be misread, since the automatic detection specifically looks for exactly 10 digits to identify seconds.
Does this account for timezones?
The ISO output reflects UTC-based conversion, not a specific local timezone display.
Is my timestamp sent to a server?
No. The conversion happens entirely in your browser.