How to Convert Excel to CSV (and CSV to Excel) Without Breaking Your Data
CSV (comma-separated values) is the lowest common denominator of data. Almost every system can import it, which makes it the go-to format for moving data between spreadsheets, databases, accounting software and online services. But the conversion between Excel and CSV has traps that quietly damage data. Knowing them saves hours.
Excel and CSV are different things
| Excel (.xlsx) | CSV | |
|---|---|---|
| Content | Values, formulas, formatting, several sheets | Plain text values only |
| Sheets | Many | One per file |
| Formatting | Fonts, colours, number formats kept | None |
| Size and speed | Larger | Small and fast |
| Best for | Working and presenting | Exchanging and importing data |
When you save as CSV, formulas become their last calculated value and all styling disappears. That is normal. It is also why you should keep your original .xlsx.
The four problems that break data
- Leading zeros vanish. A code such as 00123 turns into 123 when treated as a number. Convert with a tool that keeps such values as text.
- Accents look garbled. Excel needs a UTF-8 marker at the start of a CSV to recognise accents and non-Latin letters. Keep the UTF-8 option on.
- Semicolons instead of commas. In countries where the comma is the decimal separator, spreadsheets write semicolons between columns. Choose the separator that your target system expects.
- Dates change meaning. 03/04/2026 is March 4 in the US and April 3 elsewhere. Use the unambiguous format 2026-04-03 when you exchange data.
Excel to CSV step by step
- Open Excel & CSV Converter and choose Excel to CSV.
- Select your .xlsx file and pick the sheet.
- Choose the separator and keep the UTF-8 marker on for accents.
- Check the preview, then download the CSV.
CSV to Excel step by step
- Choose CSV to Excel and select your file.
- The tool detects the separator and shows a preview.
- Download the .xlsx file, with numbers stored as real numbers and an optional bold, frozen header row.
Values like 007 stay as text so the zeros are kept, while plain numbers such as 42 or 3.5 become real Excel numbers you can sum.
Converting to JSON
Developers often need spreadsheet data as JSON, for example to feed an app or an API. Each row becomes an object with the header names as keys. If you then need to tidy or validate the result, use the JSON Formatter & Validator.
Working with several sheets
A CSV file holds one sheet only. For a workbook with several sheets, convert them one at a time and name each file clearly, such as sales-2026-q3.csv.
Key terms: Excel to CSV, CSV to Excel, xlsx, delimiter, UTF-8 BOM, leading zeros, Excel to JSON, spreadsheet converter, comma-separated values.
Frequently asked questions
How do I convert an Excel file to CSV?
Choose Excel to CSV, select your .xlsx file, pick the sheet and separator, check the preview and download the CSV. It happens in your browser.
Why does my CSV show strange characters in Excel?
Excel needs a UTF-8 marker to recognise accents and non-Latin letters. Leave the UTF-8 marker option on when you convert.
Why does my CSV use semicolons?
In regions where the comma is the decimal mark, spreadsheet programs write semicolons between columns. You can pick comma, semicolon, tab or pipe.
Will leading zeros be kept?
Yes. Values such as 007 or 00123 stay as text when converting CSV to Excel.
What happens to formulas and formatting?
Formulas are exported as their last calculated value. Fonts, colours and number formats are not part of CSV or JSON.
Need to convert a spreadsheet file?
Try Excel & CSV Converter →Put this guide into practice
Excel & CSV Converter — Convert Excel to CSV or JSON, and CSV to Excel, free.
JSON Formatter & Validator — Format, validate and minify JSON, or convert JSON to CSV.