CSV to Excel
Turn a CSV file into an Excel workbook with real numbers. Nothing is uploaded.
Drop CSV files here
Converted on your device. Files are never uploaded.
Up to 20 files at a time.
A CSV is plain text, so it has no column widths, no number types and no protection from Excel’s guesses when you open it. FormatJet turns your CSV into an XLSX workbook with one sheet, numbers stored as numbers and columns sized to their content. It runs in your browser, so the data stays on your device.
About the formats
CSVCSV file
CSV stores a table as plain text, one row per line with commas between the values. Spreadsheets, databases and almost every data tool can read and write it.
XLSXExcel workbook
XLSX is the workbook format of Microsoft Excel since 2007: sheets of cells with formulas, formatting and charts.
Converted with Data converters (Papa Parse, yaml, fast-xml-parser), Data converters on Workers.
Questions
Will numbers be stored as numbers in Excel?
Yes, with “Store numbers and true/false as values” on, which is the default. Plain numbers become cells Excel can add up and chart, while values like 00123 stay text so their zeros aren’t lost.
Why convert a CSV to XLSX instead of opening it in Excel?
Opening a CSV directly lets Excel guess each column, which can strip leading zeros or turn codes into dates. Converting first gives you a workbook where those values are already stored the right way.
How wide are the columns?
Each column’s width is set from its content, so you can read the values as soon as the file opens, without dragging column edges.
What if my CSV is too big for Excel?
A table with more rows or columns than an Excel sheet can hold is refused, so you never get a workbook with part of your data missing.
CSV to Excel with the API
The conversion API opens later this year.
curl https://api.formatjet.com/v1/convert?to=xlsx \
-H "Authorization: Bearer fj_test_…" \
-F file=@input.csv -o output.xlsx