CSV cleaner — trim, dedupe and tidy a CSV
Paste a messy CSV and get a clean one: whitespace trimmed, duplicate rows removed, blank rows dropped and quoting fixed. It cleans entirely in your browser (0 uploads, works offline).
How to use it
- Paste your CSV.
- Toggle the cleaning options — trim, dedupe, drop blank rows, collapse spaces.
- Copy or Download the cleaned CSV.
FAQ
How do I remove duplicate rows from a CSV for free?
Paste the CSV and keep "Remove duplicate rows" on. This page keeps the header and the first occurrence of each row, dropping later exact duplicates — on your device with no upload. It also reports how many it removed.
Does it fix inconsistent quoting and stray whitespace?
Yes. It re-parses the CSV with RFC 4180 rules and rewrites it with correct quoting, and the trim option strips leading and trailing spaces from every cell.
Is my data uploaded anywhere?
No. The cleaning runs entirely in your browser and nothing is transmitted or stored, which you can confirm by turning off your Wi-Fi.
Will it change my numbers or leading zeros?
No. Values are treated as text, so identifiers like PINs and phone numbers keep their leading zeros exactly as pasted.
Limits
Deduplication matches whole rows exactly; near-duplicates that differ by a character are kept as distinct.
Related
The CSV viewer/editor lets you fix cells by hand; the data anonymiser masks PII columns.
Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.