UlvixorDate Format Converter
Convert dates between the most common formats (YYYY-MM-DD, MM/DD/YYYY, DD/MM/YYYY), ISO 8601, and Unix timestamp, with automatic detection of the input format. Everything is calculated in your browser, with no data sent to a server.
How it works
- Type or paste the date you want to convert (or use the built-in example).
- Choose the input format, or leave it on 'Auto-detect' so the tool identifies it for you.
- Select the output format you want, including ISO 8601 or Unix timestamp.
- The result updates instantly as you change the date or the formats.
- Copy the result with one click.
Use cases
- Convert a form date (DD/MM/YYYY) into the ISO 8601 format an API expects.
- Turn a Unix timestamp stored in a database into a readable date.
- Adapt dates exported from a spreadsheet to the format another system needs.
- Quickly check what date a specific Unix timestamp corresponds to.
Use cases
- Convert a form date (DD/MM/YYYY) into the ISO 8601 format an API expects.
- Turn a Unix timestamp stored in a database into a readable date.
- Adapt dates exported from a spreadsheet to the format another system needs.
- Quickly check what date a specific Unix timestamp corresponds to.
Common mistakes
- Trusting 'Auto-detect' with ambiguous dates like 03/04/2026.That date could be April 3rd or March 4th depending on the format. Manually choose the exact input format (DD/MM/YYYY or MM/DD/YYYY) to avoid misreading the day and month.
- Pasting a Unix timestamp in milliseconds and expecting it to be interpreted correctly.The tool interprets the Unix timestamp in seconds, not milliseconds. If your value is in milliseconds (13 digits), divide it by 1000 before pasting it.
- Assuming the result uses a different time zone than your browser's.Conversions use your device's local time zone, except when working with ISO 8601 with an explicit offset or a Unix timestamp, which are time-zone independent.
Frequently asked questions
No. Date conversion is calculated entirely in your browser using the date-fns library. No date is ever sent to or stored on a server.
Manually select the input format that matches your date from the dropdown menu. This avoids ambiguity — for example, between 03/04/2026 in DD/MM/YYYY versus MM/DD/YYYY format.
It's the number of seconds elapsed since January 1, 1970 (00:00:00 UTC). It's widely used in databases and APIs to represent dates compactly.
Conversions use your browser's local time zone, except when working with ISO 8601 with an explicit offset or a Unix timestamp, both of which are time-zone independent.
Alternatives
In code, functions like strftime in Python or date-fns (the same library this tool uses) in JavaScript handle the same conversions. This tool is useful for a one-off conversion without writing or running any code.