CSV Cleaner

About CSV Cleaner & Data Sanitizer

CSV Cleaner is a powerful online tool that automatically sanitizes and cleans your CSV and JSON data files. Remove empty rows and columns, trim whitespace, strip special characters, eliminate duplicates, and normalize formatting—all in your browser without uploading data to a server.

What does CSV Cleaner do?

CSV Cleaner sanitizes data by removing empty rows and columns, trimming whitespace, stripping non-printable characters, eliminating duplicate rows, and normalizing line breaks. It helps prepare messy data for analysis, import, or further processing.

Is my data secure?

Yes. All data cleaning happens locally in your browser using JavaScript. Your files never leave your device, ensuring complete privacy for sensitive information like customer lists, financial records, or confidential datasets.

What file formats are supported?

CSV Cleaner supports CSV files (with various delimiters: comma, semicolon, tab, pipe) and JSON files (arrays of objects). Both formats can be cleaned and exported to either CSV or JSON format after processing.

What does 'Remove special characters' do?

This option strips non-printable and control characters from your data, keeping only standard ASCII characters (letters, numbers, basic punctuation). It's useful for cleaning data imported from legacy systems or databases that may contain hidden formatting characters.

How are duplicate rows detected?

Duplicate rows are identified by comparing all column values in each row. If two or more rows have identical values in all columns, only the first occurrence is kept. This helps eliminate redundant data entries.

Can I preview the cleaned data?

Yes. The tool displays a preview of your cleaned data (up to 100 rows) in a table format. You'll also see a detailed cleaning report showing how many empty rows, empty columns, duplicates, and cells were cleaned.

How do I read the Column Quality Report?

After cleaning, a per-column table profiles your data: fill rate (% of non-empty cells, color-coded green/amber/red), blank count, distinct values, duplicate values, and an auto-detected type (integer, decimal, date, boolean, text, or mixed). Use it to spot unreliable columns—low fill rates or a 'mixed' type—before importing into a database, BI tool, or model.

Which delimiter should I use for European CSV files?

Many European locales export CSV with a semicolon (;) delimiter because the comma is used as a decimal separator. If your file looks like one giant column, switch the Delimiter option to Semicolon. Tab and Pipe are also supported, and Auto-detect handles most files automatically.

Is the CSV export RFC 4180 compliant, and are there file-size limits?

Yes—on export, any cell containing the delimiter, a double quote, or a line break is wrapped in double quotes with embedded quotes doubled (""), per RFC 4180. The tool also fixes UTF-8 encoding by stripping only invisible control characters while preserving accented and non-Latin text. All processing runs in your browser, so practical limits depend on your device's memory; files up to a few hundred MB work on modern desktops, while very large files are best split first.