Convert XLSX to CSV
Upload a .xlsx or .xls file and get back a CSV file. Types are preserved rather than flattened to text. Free, no registration, up to 10MB.
Click to upload or drag and drop
CSV, Excel, SQLite, SQL, DBF (max 10 MB)
How your data is typed in CSV
Generated from the converter's own CSV type mapping — this is what it actually emits, not an example.
| Your data | CSV type |
|---|---|
| Whole number | text (CSV has no types) |
| Decimal (money) | text (CSV has no types) |
| Floating point | text (CSV has no types) |
| True / false | text (CSV has no types) |
| Date | text (CSV has no types) |
| Date and time | text (CSV has no types) |
| Short text | text (CSV has no types) |
| Long text | text (CSV has no types) |
| Binary data | text (CSV has no types) |
Working from a .xlsx file
A .xlsx file is OOXML - a zip of XML parts - and holds up to 1,048,576 rows per sheet. It also states its number formats explicitly, which is why more type information survives the trip out of .xlsx than out of any other spreadsheet format.
- →The workbook is opened for cached values only, so a formula cell converts as the number Excel last calculated for it. A file written by a script that never opened it in Excel can have those cells empty.
- →A column's number format is taken from the first data row that states one, so formatting only the header row tells the reader nothing about the column.
- →Accounting formats count as money even with no symbol in them: #,##0.00 is read as fixed-point, not as a plain number.
The shape of the CSV files you get
CSV is where the type information stops, so what is left to describe is the file itself: how a row is terminated, which fields are quoted, and how a value that used to have a type is spelled out as characters.
- →Rows end with a carriage return and a line feed, the RFC 4180 ending, while a newline inside a quoted field stays the single character it always was. The encoding is UTF-8 with no byte-order mark in front of it.
- →Quotes go on only where they are needed - a field holding a comma, a double quote or a newline - and a quote inside a field is doubled rather than escaped with a backslash. Every other field is written bare.
- →Decimal values are written digit for digit and never through a floating-point number, so a money column that was exact in the source is still exact in the file. Booleans are written lower case, as true and false, which is the spelling this converter's own reader takes back as a boolean.
Reading XLSX
- →Numbers, dates and booleans are read as Excel stored them, never converted to text and re-parsed.
- →Cell number formats are read out of .xlsx workbooks, so a column formatted as currency becomes a fixed-point decimal rather than a floating-point number — which is how money avoids acquiring a rounding tail. Legacy .xls is the exception: the xlrd path exposes no formats, so its currency columns come across as ordinary numbers.
- →A column formatted as a date becomes a date, not a timestamp at midnight; one formatted with a time keeps its time.
- →One sheet becomes one table. Empty sheets are skipped, and sheet names are sanitised for the target.
Writing CSV
- →One file per table, with a header row.
- →NULL is written as an empty field, never the word "None".
- →Binary data is written as hex, which is reversible.
What you get
A ZIP containing <table>.csv. If anything about your data needed a judgement call, a _warnings.txt explains it.
Questions
- Is converting XLSX to CSV free?
- Yes. Files up to 10MB convert free with no account. There is a limit of five conversions per day per IP address.
- Will my XLSX data keep its types in CSV?
- Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real CSV types rather than everything becoming text. The mapping table above shows exactly what you get.
- Do you store my file?
- No. The file is written to a temporary directory, converted, and the directory is deleted as soon as your download has been sent.