Add Row Numbers to CSV
Paste CSV text, choose the starting number, prefix, zero padding and whether the id column goes first or last.
A QUICK WALKTHROUGH
How to use this tool
- Paste CSV text up to 2 MB and choose numbering options.
- Keep the first record as the header and add configured ids to data records.
- Review and copy the CSV locally.
Header and numbering
The first parsed record is retained as the header. Choose the starting number, optional prefix, zero padding up to 20 digits, and first or last column placement. Defaults remain id, 1, no prefix, no padding and first column.
CSV and errors
Quoted commas, escaped quotes, and quoted line breaks are preserved. Empty input produces empty output; malformed CSV or unsafe numbering options are rejected without partial output.
Local limits and privacy
Input is limited to 2 MB, 50,000 records, and 500 fields per record. Processing stays in your browser; dialects and encodings are not detected.
GOOD TO KNOW
Common questions
What can I configure?
Set the starting number, optional prefix, zero-padding width, and whether the id column is first or last.
Are headers numbered?
No. The first parsed record remains the header.
Is my CSV uploaded?
No. Processing is local in your browser.