CSV Cleaner

Clean messy CSV files with deduping, text normalization, whitespace cleanup, encoding repair, and more.

Cleaning options

How to use this CSV cleaner

  1. Upload a CSV file or paste CSV text into the input.
  2. Choose the cleanup options you want, including whitespace, duplicates, text case, headers, delimiters, and encoding repair.
  3. Click Clean CSV to refresh the preview and counts, then download the cleaned file.

CSV Cleaner features

  • Remove duplicate rows after the selected cleanup rules are applied.
  • Normalize text case across CSV values.
  • Trim leading and trailing whitespace from cells.
  • Collapse repeated internal spaces from messy exports.
  • Remove empty rows and optional blank columns.
  • Repair common mojibake such as broken smart quotes and accented characters.
  • Process large CSV files with 1 million+ rows on modern desktop browsers.
  • Decode uploaded files as UTF-8, Windows-1252, or ISO-8859-1.
  • Clean headers into readable labels, lowercase labels, snake_case, or kebab-case.
  • Export with comma, semicolon, or tab delimiters.
  • Preview cleaned rows before downloading.

What CSV cleaning helps fix

CSV exports from CRMs, spreadsheets, email platforms, and databases often contain repeated rows, padded cells, inconsistent casing, blank lines, unnamed columns, mixed delimiters, and broken characters. This cleaner handles those everyday cleanup steps before you import data into another system.

How CSV cleaning works

The tool parses CSV in a browser worker, applies the selected cell and row transforms chunk by chunk, deduplicates rows by their cleaned values, and serializes a fresh CSV for download. Uploaded files are decoded locally with the selected encoding and are not sent to a server. Exact duplicate removal keeps row keys in memory, so very wide files with many unique rows can still be limited by available browser memory.

CSV cleaner FAQ

Are my CSV files uploaded?
No. File reading, parsing, cleaning, preview, and download all run in your browser.
How are duplicate rows detected?
Duplicate rows are compared after the selected cleanup options are applied, so rows that only differ by spacing, casing, or repaired characters can be removed together.
What encoding should I choose?
Use UTF-8 for most modern exports. Try Windows-1252 or ISO-8859-1 when smart quotes, accented characters, or symbols look broken after loading a file.