CSV Cleaner
Free online CSV cleaner. Remove empty rows, deduplicate rows, trim whitespace, fix stray quotes, strip BOM, and drop empty columns.
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What is CSV Cleaner?
The CSV Cleaner is a free, browser-based tool for tidying up CSV data. It removes empty rows, deduplicates rows, trims whitespace, fixes stray quote marks, strips the UTF-8 BOM, and drops fully-empty columns — all without uploading your data anywhere.
Key Benefits
- 100% client-side — no upload, works offline, safe for sensitive data.
- RFC-4180-aware parser handles quoted fields, embedded delimiters, and embedded newlines.
- Independent toggles let you run exactly the cleaning steps you need.
- Header-aware deduplication keeps your column titles intact.
- Live preview table and one-click download as a UTF-8 .csv file.
Common Use Cases
- •Cleaning messy CSV exports before importing into a database or spreadsheet.
- •Removing duplicate records from a customer or product list.
- •Stripping whitespace and BOM artifacts from CSVs saved by different editors.
- •Tidying survey or form data that contains blank rows and columns.
How to Use the CSV Cleaner
- Paste or upload your CSV: Paste CSV data into the editor, or click Upload to load a .csv or .txt file. You can also click Sample to try a demo dataset.
- Pick the delimiter: Select the correct delimiter for your data: comma, semicolon, tab, or pipe. The parser uses RFC-4180 rules.
- Toggle cleaning options: Turn on the cleaning steps you need: trim whitespace, remove empty rows, remove duplicate rows, remove empty columns, collapse spaces, fix quotes, strip BOM.
- Copy or download: Review the live preview and stats, then click Download to save the cleaned .csv file or Copy to copy it to your clipboard.
Key Features
- Remove empty rows, duplicate rows, and fully-empty columns with independent toggles.
- Trim leading and trailing whitespace from every field automatically.
- Collapse runs of multiple spaces into a single space for tidy data.
- Strip the UTF-8 BOM and fix stray leading or trailing quote marks.
- Header-aware deduplication keeps the first row while removing duplicate data rows.
- RFC-4180 parser handles quoted fields, embedded delimiters, and embedded newlines.
Frequently Asked Questions
Is my data uploaded to a server?
No. The CSV Cleaner runs entirely in your browser. Your data is never sent to any server, which makes it safe for customer lists, financial data, and other sensitive information.
What does "remove duplicate rows" do?
It removes rows where every field is an exact match to an earlier row, keeping only the first occurrence. When "First row is a header" is on, the header row is always kept and only data rows are checked for duplicates.
How are quoted fields handled?
The tool uses a proper RFC-4180 state-machine parser, so quoted fields, embedded delimiters, embedded newlines, and doubled double-quotes ("") are all parsed correctly. The "Fix stray quote marks" option additionally removes lone leading or trailing quote characters that are not part of valid RFC-4180 escaping.
Will this break my CSV formatting?
No. Fields that need quoting (they contain the delimiter, a quote, or a newline) are re-quoted automatically on output following RFC-4180 rules, so the cleaned CSV is always valid.