What a CSV file is, compared with an Excel workbook
An Excel workbook (.xlsx) is a rich container. It can hold several sheets, formulas, number formats, colors, charts and more. A CSV file, short for comma-separated values, is far simpler: plain text, one row per line, with the cells of each row separated by commas.
That simplicity is the point. Almost every database, import form, analytics package and programming language can read CSV, while not all of them understand Excel files. Converting to CSV strips a spreadsheet down to its data so that other systems can use it.
The trade is that everything beyond the data is lost. Colors, column widths, charts and formatting do not exist in CSV. Formulas are not kept as formulas either; you get the values the cells display.
Why you might convert a spreadsheet to CSV
The most common reason is an import. A mailing list tool, online shop, accounting package or CRM asks for a CSV upload, and your data lives in an Excel file. Another reason is scripting: a few lines of code can read a CSV with no special library.
CSV is also handy for sharing data that has to survive for years, since a plain text file will open anywhere. And it makes a good midpoint when you want to clean data in a text editor or compare two exports line by line.
One limit to know before you start: a CSV can only hold a single table. This tool converts only the first sheet of the workbook, so if your data is spread across several sheets you will need to move the one you want to the front, or convert them one by one.
How to convert Excel to CSV with this tool
- Drag an Excel file (.xlsx or .xls) onto the drop area, or click it to browse.
- A table preview of the first rows of the first sheet appears. Only the first 8 rows are shown, but the conversion includes every row.
- Click Convert. The sheet is turned into comma-separated text.
- Click Download when it appears. The file keeps your original name with a .csv ending.
- Use Start over to convert another file.
Reading and converting happen in your browser. Your spreadsheet is not sent to a server. If the file cannot be read, a message tells you to check that it is a valid Excel file.
Checks and common problems
Open the CSV in a text editor after downloading and look at the first few lines. Make sure the headers are in the first row and that values containing commas are wrapped in quotes, which is how the format keeps them in one cell.
Dates and numbers come out as the cell shows them, so a date formatted a certain way in Excel will be written in that form. If a system you import into expects a specific date style, adjust it in the spreadsheet first.
Leading zeros, such as in postcodes or ID codes, are only safe if Excel stored the cell as text. If you reopen the CSV in a spreadsheet program, it may strip zeros again, which is a spreadsheet habit rather than a problem with the file.
To go the other way, use CSV to Excel. If your destination wants JSON rather than CSV, CSV to JSON may be more direct.