Rename Columns in CSV Files Online

Can I rename all columns in a CSV file at once?

Yes. The tool shows an editable name field for every column. Change any number of them in a single pass.

Are there restrictions on what I can name columns in a CSV file?

Avoid commas, newlines, and null characters in column names. Most other special characters including spaces, hyphens, and dots are safe.

Does renaming columns affect the row data in the CSV file?

No. Only the column headers change. All row values stay exactly the same.

Is my data private?

Yes — completely. Your file is never uploaded to any server. Everything runs locally in your browser using WebAssembly — processing happens entirely inside your tab. Once you close the tab, nothing is retained.

What is the maximum file size?

The free limit is 50 MB. For larger files, performance depends on your device's available memory — most modern machines handle 500 MB to 1 GB comfortably.