Add a CSV file. It becomes an Excel workbook with real numbers and dates, made on your device.
Delimiter
Bold and kept in view as you scroll.
Values like 007 or 1,234 stay as text.
Your files will appear here.
What it does
CSV to Excel turns each CSV file into an Excel workbook (.xlsx) with one sheet, ready to sort, filter and sum.
Delimiter: Auto guesses between comma, semicolon, tab and pipe. Choose Comma, Semicolon, Tab or Pipe if the guess is wrong.
First row is the header, on by default, makes the first row bold and keeps it in view as you scroll. The header row always stays text.
Convert numbers and dates, on by default, stores plain numbers as numbers, dates such as 2026-01-31 as dates, and TRUE and FALSE as Excel’s TRUE and FALSE. Codes such as 007 and values such as 1,234 stay text, exactly as written.
Rows with fewer values than the longest row get empty cells at the end. Every other value is text, and a value starting with = is never a formula.
How to use it
Drop your CSV files on the box, paste them, or select Choose files. Select “Try a sample” to see an example.
Check the options. Each file shows its rows, columns, encoding and delimiter, such as “7 rows × 8 columns · UTF-8 · semicolon”.
Select Download XLSX for one file, or Download all to save every workbook in one ZIP file.
Press Esc to stop a conversion that’s still working.
Good to know
You can add up to 20 files at a time, each up to 20 MB. It reads .csv, .tsv and .txt files.
A sheet holds up to Excel’s 1,048,576 rows and 16,384 columns, and a cell up to 32,767 characters. A workbook made here holds up to 10,000,000 cells, counted as the rows times the longest row, and up to 100 MB of sheet data.
A workbook made from a large CSV can be over 10 MB, the most Excel to CSV takes, so it may not convert back to CSV here.
Use one kind of line break in a file. If Windows (CRLF) and Unix (LF) line breaks are mixed, a value can keep a stray carriage return (\r).
Privacy
Your CSV files are processed on your device: the tool runs in your browser, and your files aren’t uploaded.
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Frequently asked questions
Why do numbers with leading zeros stay text?
A value such as `007` or `00123` is usually a code, a postcode or an ID, and Excel would drop its zeros if it were a number. So only plain numbers, such as `12.50`, `-5` or `1e3`, become numbers. Values with a thousands separator or a decimal comma, such as `1,234` or `1,5`, IDs with 16 or more digits, which Excel would round, and values starting with `+` stay text too, exactly as written. Turn off Convert numbers and dates to keep every value as text.
How are dates handled?
Dates from 1 March 1900 written as `2026-01-31` become Excel dates, and `2026-01-31 14:30` or `2026-01-31T14:30:00` become dates with a time, so you can sort and filter them. Other forms, such as `31/01/2026` or `01/31/2026`, stay text, because the same digits mean different days in different countries. TRUE and FALSE, in any case, become Excel's TRUE and FALSE.
Which encodings and delimiters does it read?
It reads UTF-8, with or without a byte order mark, and UTF-16 with its byte order mark. A file that isn't valid UTF-8 is read as Windows-1252, the Western European encoding older programs save. Delimiter Auto guesses between comma, semicolon, tab and pipe, or you can choose one. The line under each file names both, such as “7 rows × 8 columns · UTF-8 · semicolon”.
Can I convert several files at once?
Yes. Add up to 20 files, and each becomes its own workbook with one sheet named after the file, such as `orders.xlsx` from `orders.csv`. Select Download all to save every workbook in one ZIP file.
Can a value run as a formula when the workbook opens?
No. A value starting with `=`, such as `=SUM(A1:A2)`, is put in the workbook as text, so Excel shows it as written and never runs it. No cell in the workbook holds a formula.
Are my files uploaded?
No. Your CSV files are converted by your browser, on your device, and your files aren’t uploaded. The workbooks are made on your device too, and they’re saved only when you select Download.