Convert CSV to Excel: Why Your Data Looks Wrong (And How to Fix It)
Last updated: 2026-03-22
You double-click a CSV file. Excel opens it. Everything looks fine until you notice that zip code 07102 became 7102, the date 01/02/2026 became January 2nd (but you meant February 1st), and all the Japanese characters are question marks. Welcome to the CSV-to-Excel experience.
The 5 Most Common Problems
| Problem | What Happens | Why | Fix |
|---|---|---|---|
| Leading zeros stripped | 07102 becomes 7102 | Excel treats it as a number | Import as text, or prefix with apostrophe |
| Dates reformatted | 01/02/2026 becomes Jan 2 or Feb 1 | Excel guesses date format based on locale | Import with explicit date format |
| Long numbers as scientific notation | 1234567890123 becomes 1.23E+12 | Excel default number format | Import as text or format cells first |
| Encoding issues (mojibake) | Japanese/Chinese/accented chars become garbage | CSV is UTF-8, Excel expects ANSI | Use Data > From Text with UTF-8 encoding |
| Delimiter confusion | Columns not split correctly | CSV uses semicolons (European) but Excel expects commas | Use Data > From Text with correct delimiter |
The Right Way to Open CSV in Excel
Do NOT double-click the CSV file. Instead:
- Open Excel first (empty workbook)
- Go to Data > From Text/CSV (or Data > Get Data > From File > From Text/CSV)
- Select your CSV file
- In the import wizard, set: encoding (UTF-8), delimiter (comma/semicolon/tab), and column data types
- For columns with leading zeros (zip codes, phone numbers, IDs): set to Text
- For date columns: set the correct date format
- Click Load
This takes 30 seconds longer than double-clicking but prevents every problem listed above.
The Encoding Problem Explained
CSV files can be encoded in UTF-8, UTF-8 with BOM, ANSI, Latin-1, or Shift-JIS (and others). Excel on Windows defaults to ANSI encoding when you double-click a CSV. If the file is UTF-8 (which most modern CSVs are), non-ASCII characters break.
The fix: when importing, explicitly select UTF-8 encoding. Or use our CSV to Excel converter which auto-detects encoding and produces a properly formatted XLSX file.
Related Tools
According to Microsoft Support, using the Text Import Wizard gives full control over how Excel interprets CSV data.
As RFC 4180 specifies, CSV files should use comma delimiters, but regional variations using semicolons are common in European locales.