CSV or Excel tool

CSV to Excel

Turn a CSV file into a genuine XLSX workbook in your browser, keeping column headers and protecting values such as postcodes and IDs that must stay text.

Add files

Drop CSV files here, or choose files. Everything stays on this device.

Options

First row is a header

Waiting for files

Accepted input

CSV or TSV files

Limits

Up to 20 MB per CSV/Excel file and up to 100000 rows.
CSV, TSV, XLSX and JSON inputs are supported in this category.

Local processing

Files are read in your browser and are never uploaded to a server.
Nothing is stored after you close or reload the page.

How to use CSV to Excel

Add the CSV file you want to convert.
Leave "First row is a header" on if the first line contains column names.
Press CSV to Excel and download the generated XLSX workbook.

What it does

Writes a valid XLSX file that opens in Excel, LibreOffice and Numbers.
Keeps long numbers and codes with leading zeros as text so they are not mangled.
Exports a notes file describing how many cells were protected as text.

Limits and things to know

Only a single sheet is created; the source CSV has no sheet structure to preserve.
Formulas, styling and charts cannot be produced because CSV has no such information.

Example

Turning a staff export into a workbook

Convert a CSV such as id,name,postcode with a value like 00123 in the postcode column. The generated XLSX keeps 00123 as text instead of dropping the leading zeros, and the notes file reports how many cells were protected.

Frequently asked questions

Will my leading zeros survive?

Yes. Values that look numeric but start with zero are written as text and marked in the notes file so a spreadsheet does not strip them.

Does this execute formulas from the CSV?

No. CSV has no formulas, and dangerous prefixes such as = or @ are guarded so a spreadsheet does not treat them as executable.

Can I convert several CSV files at once?

Not in this tool; it converts one file per run. Merge the CSVs first if you need a single workbook.

Runs entirely in your browser on ap98.com. Files are never uploaded.