Date Format Converter
Convert dates between ISO 8601, DD/MM/YYYY, MM-DD-YY, Unix timestamps, and custom token formats. Validates calendar dates in your browser.
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What is Date Format Converter?
The Date Format Converter is a free online tool that parses a date in one format and reprints it in another. It supports ISO 8601, day/month/year and month/day/year orders, long English month names, Unix timestamps, and custom tokens, with calendar validation, entirely in your browser.
Key Benefits
- Make DD/MM versus MM/DD explicit so logs and spreadsheets stop swapping days and months
- Reject impossible dates instead of rolling them into the next month
- See ISO, locale, and Unix forms of the same instant in one table
- Works offline with no account and no upload of the dates you convert
Common Use Cases
- •Turning a US MM/DD/YYYY export into ISO 8601 for an API
- •Reading a Unix timestamp from a log as a local calendar date
- •Reformatting invoice dates from DD.MM.YYYY to YYYY-MM-DD
- •Checking whether 29 February is valid for a given year
How to Use the Date Format Converter
- Enter the date: Paste a date string such as 2024-08-20, 20/08/2024, August 20, 2024, or a Unix timestamp.
- Choose the input format: Leave Auto-detect on, or pick ISO, DD/MM/YYYY, MM/DD/YYYY, or a custom token pattern so 05/02 is unambiguous.
- Choose the output format: Select a preset or type tokens like YYYY-MM-DDTHH:mm:ss. The converted value and a preset table update immediately.
- Copy or download: Copy the converted date, download every preset as TSV, or swap formats to reverse the conversion.
Key Features
- Convert between ISO 8601, DMY, MDY, compact YYYYMMDD, and RFC-style strings
- Custom tokens including YYYY, MM, DD, 12-hour clocks, month names, and Unix X/x
- Auto-detect with a warning when more than one calendar date is possible
- Rejects impossible dates such as 31 February and mismatched weekdays
- Live table of every preset plus copy and TSV download
- Runs entirely in-browser — nothing is uploaded
Frequently Asked Questions
Is 05/02/2024 February 5 or May 2?
It depends on the input format. DD/MM/YYYY is 5 February. MM/DD/YYYY is May 2. Auto-detect prefers day-first (DD/MM/YYYY) and lists the other parse under also valid as when both are real calendar dates.
How are two-digit years interpreted?
YY values 70-99 become 1970-1999. Values 00-69 become 2000-2069. Use YYYY when you need years outside that window.
Does Unix conversion use UTC or local time?
Unix X and x are converted with the JavaScript Date in your local timezone. The calendar fields you see match what your OS clock would show for that timestamp.
Does my date leave the browser?
No. Parsing and formatting run in JavaScript on your device. Nothing is uploaded and the page works offline after it has loaded.