Clean CSV Data Online Free

Large CSV Viewer cleans CSV data directly in your browser. Use Find & Replace (Ctrl+H) to standardize inconsistent values, column filters to find and fix blank or null cells, and the duplicate finder to remove duplicate rows. Edit any cell inline with double-click. Export your cleaned dataset as CSV, JSON, or Excel. Free, no account required.

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Clean messy CSV data online for free — trim whitespace, fix encoding, remove blank rows, and standardize values. No install, no account needed.

Messy CSV data — inconsistent values, trailing whitespace, blank rows, duplicate entries — causes broken imports and inaccurate analysis. Large CSV Viewer gives you the tools to find and fix data quality issues directly in the browser, without writing a single line of code.

Key features

  • Find & Replace to standardize inconsistent values (Ctrl+H)
  • Column filters to locate blank, null, or malformed cells
  • Inline cell editing to fix individual values
  • Export cleaned data as CSV, JSON, or Excel

How it works

  1. Upload your messy CSV. Open your CSV file in the viewer. Use column stats (click any column icon) to immediately see null counts and data type issues.
  2. Find and fix issues. Use Find & Replace (Ctrl+H) to standardize values like 'N/A' → '' or 'United States' → 'US'. Use column filters to isolate blank or malformed rows.
  3. Export clean data. Once your data is clean, export the full dataset as CSV, JSON, or Excel from the File menu.

Ready to try it?

Free, instant — no account or install needed.

Open CSV Viewer →

Frequently asked questions

How do I remove blank rows from a CSV?

Use a column filter with the 'Is Not Empty' operator on a required column (like an ID). This filters out any row where that column is blank. Export the filtered result.

How do I trim whitespace from CSV values?

Use Find & Replace with regex mode enabled. The pattern ^\s+|\s+$ matches leading and trailing whitespace. Replace with an empty string to trim all values in a column.

Can I standardize inconsistent values like 'USA' and 'United States'?

Yes. Use Find & Replace (Ctrl+H), enter the variant you want to change in the Find field, and enter the standardized value in the Replace field. Apply to a specific column for precision.

How do I find duplicate rows?

Use the column filter with the 'Equals' operator to isolate rows matching a specific value, or visit the /csv-duplicate-finder page for a dedicated duplicate detection workflow.

Is the CSV cleaner free?

Yes, completely free. No account, no file size limit, no paywall.