About the Time Converter
Timestamps show up in many different shapes across systems — Unix seconds, Unix milliseconds, ISO 8601 strings, and even MongoDB ObjectIds, which secretly embed a creation timestamp in their first 8 hex characters.
This tool automatically detects the format of whatever timestamp you paste in and converts it to a human-readable date, with timezone support.
How it works
- Paste a timestamp, date string, or MongoDB ObjectId into the input box.
- The tool automatically detects the format (Unix seconds, Unix milliseconds, ISO string, or ObjectId) and shows the corresponding date and time.
- Choose a timezone to see the same moment in time expressed for that region.
Common use cases
- Debugging API timestamps: Instantly converting a `created_at: 1716239022` field from an API response into a readable date, without remembering whether it's in seconds or milliseconds.
- Extracting a MongoDB document's creation time: Pasting a MongoDB ObjectId to reveal exactly when that document was inserted, since the timestamp is embedded in the ID itself.
- Comparing times across timezones: Converting a UTC timestamp from a server log into your local timezone to correlate it with when you observed an issue.
Frequently asked questions
How does the tool know if a number is seconds or milliseconds?
It uses digit count as a heuristic — a 10-digit number is treated as Unix seconds (valid for dates up to the year 2286), while longer numbers are treated as milliseconds. If your value is ambiguous or unusually formatted, double-check the detected type shown above the result.
What is a MongoDB ObjectId and why does it have a timestamp?
A MongoDB ObjectId is a 12-byte (24 hex character) identifier where the first 4 bytes encode the Unix timestamp (in seconds) of when the ID was generated — this tool decodes just that portion to show the document's approximate creation time.
Why did my input show as 'Invalid Format'?
The string didn't match a numeric timestamp, a 24-character hex ObjectId, or a format JavaScript's native Date parser recognizes (like ISO 8601). Double-check for typos or an unsupported custom date format.
Does this tool account for daylight saving time?
Yes — timezone conversions use standard timezone database rules, which include daylight saving transitions where applicable for the selected region.
This tool runs entirely in your browser — nothing you enter is sent to a server. Read more in the Privacy Policy, or browse the full list of tools.