Guide
Day/month or month/day? Handling dates in international spreadsheets
03/04/2026 is 3 April in most of the world and March 4 in the United States. When a column mixes both, sorting and filtering silently go wrong.
The reliable fix is evidence: if any date in the column has a first number above 12, the column is day/month; if the second number exceeds 12, it is month/day. When no date proves it, the order is ambiguous and should be confirmed by a person, not guessed.
For exchange between systems, store dates as YYYY-MM-DD (ISO 8601). Excel, Google Sheets and databases all read it the same way.