Excel to CSV converter

What converting to CSV keeps

A workbook holds much more than a CSV can: several sheets, formulas, formatting, charts, comments and pictures. A CSV holds one table of text. So converting keeps the values and drops the rest:

• Formulas keep their last calculated value. If the workbook was saved by a program that did not calculate them, cells can be empty; open and save it in Excel first.
• Every sheet becomes its own CSV file, named after the sheet, with Every sheet on; off converts only the first.
• Charts, macros, pictures and formatting are not carried over.

Values as displayed, or as stored

Excel stores a date as a number of days and shows it formatted, and stores 0.5 but may show 50%. Values as displayed, on by default, writes what you see in Excel: 12/10/2026 and 50%. Switch it off to write the stored values, 46307 and 0.5, which is often better for importing into a database or a script that does its own formatting. Whichever you choose, check a few date columns after converting, since date formats are where spreadsheets and CSV files most often disagree.

Making Excel open the CSV correctly

Excel guesses how a CSV was written, and two guesses commonly go wrong. Add a BOM for Excel, on by default, puts an invisible marker at the start of the file that tells Excel it is UTF-8, so accented letters, Arabic or Chinese do not turn into odd symbols. And in countries that write decimals with a comma, such as France, Germany and Brazil, Excel expects a semicolon between fields; choose Semicolon there, or every row lands in one column.

From CSV to a workbook

Switch the direction to make an XLSX from CSV, TSV or JSON files. Detect numbers stores numbers as numbers, so Excel can add them up and sort them, while codes with leading zeros such as 007 and postal codes stay as text. Each file becomes one workbook; JSON should be a list of objects, one per row. The same direction re-saves old XLS and ODS files as modern XLSX.

In our test, the same 100,000 row table took 5.0 MB as CSV and 4.5 MB as an XLSX saved by Excel; reading the XLSX in JavaScript took 10 seconds against half a second for the CSV. CSV, Excel or JSON has the full comparison. To look through a big CSV without Excel, the CSV viewer opens it with search and filters.

If something goes wrong

• Everything is in one column in Excel. Your Excel expects semicolons. Convert again with Semicolon.
• Accents look wrong. Keep Add a BOM for Excel on.
• Dates became numbers. Values as displayed was off. Switch it on.
• A password protected workbook will not open. Remove the password in Excel first; protected files cannot be read here.