Date Format Converter

Convert a whole column of dates between DD/MM/YYYY, MM/DD/YYYY, ISO, Excel serial numbers and Unix time.

How to use

1. Paste a column of dates. Mixed formats are fine, including Excel serial numbers and Unix timestamps.
2. Pick the output format, or build your own with tokens like DD.MM.YY.
3. Copy the results and paste them back into Excel.

FAQ

Why does Excel show dates as numbers like 46329?

Excel stores dates as the number of days since 30 Dec 1899. This tool converts them both ways.

How are dates like 03/11/2026 handled?

They are ambiguous, so the tool assumes day first (UAE/UK) unless you choose month first. Any line where a number is above 12 is detected automatically.

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