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Trim cells, remove blank rows, normalize line endings, and remove duplicate identical rows without uploading your data.
Rows: 0 · Columns: 0 · Input size: 0 B
Trim cells, remove blank rows, normalize line endings, and remove duplicate identical rows without uploading your data.
Selected file contents are processed locally in your browser for supported workflows. This privacy build does not intentionally load ads, analytics, remote fonts, or third-party runtime scripts.
Use the controls on this page, review the output in your browser, then copy or download the result.
CSV exports often include extra spaces, blank rows, inconsistent line endings, or repeated rows. Cleaning those safe issues makes datasets easier to import, compare, and review.
This tool avoids destructive transformations. It preserves column order and values except for trimming whitespace, removing blank rows, and deleting exact duplicate rows.
CSV exports from spreadsheets often carry small, mechanical problems: extra spaces around values, blank lines left from manual editing, and rows repeated by a copy-paste mistake or a duplicate export run. This tool applies a small, fixed set of safe transformations instead of guessing at data quality: it does not lowercase text, does not remove empty cells inside an otherwise valid row, does not reorder columns, and does not attempt to repair a row with the wrong number of columns.
Cleaning runs in three steps using the same hand-written CSV parser as the CSV to JSON converter on this site: every cell is trimmed of leading and trailing whitespace, rows where every cell is empty after trimming are dropped, and any row whose trimmed cells exactly match an already-seen row is dropped as a duplicate. The header row gets no special treatment; it passes through the same trim and duplicate check as every other row.
| Issue | Handled automatically |
|---|---|
| Leading or trailing space in a cell | Trimmed |
| A fully blank line | Removed |
| An exact duplicate row, after trimming | Removed |
| A row with a different column count than the rest | Kept unchanged, only flagged with a warning |
| Internal double spaces inside a cell | Kept as typed |
| Case differences, such as Alice versus alice | Treated as a different row, not deduplicated |
The Sample CSV button loads six raw lines, including inconsistent spacing, a repeated row, and a blank line:
name, city, note Alice , Bangkok , hello Bob, Paris, cafe Alice , Bangkok , hello Chao, Taipei, unicode
Cleaning it removes the blank line and the repeated Alice row, and trims the stray spaces around every value, leaving:
name,city,note Alice,Bangkok,hello Bob,Paris,cafe Chao,Taipei,unicode
Six input lines became four output rows: one header and three unique data rows. The duplicate row was recognized only after trimming made Alice with a trailing space and Alice with a leading space compare equal; two rows differing only by capitalization, such as Alice and alice, would not be merged, since the duplicate check compares trimmed values exactly, not case-insensitively.
Yes. You can paste, clean, preview, copy, and download CSV without signup.
No. CSV files are read and cleaned locally in your browser.
The tool trims cell whitespace, removes blank rows, normalizes line endings, and removes duplicate identical rows.
No. Column order is preserved. The tool avoids destructive reshaping.
The tool shows a friendly warning and preserves your original input.
No. Deduplication only matches rows whose trimmed cells are exactly equal; near-duplicates caused by capitalization or internal spacing differences are both kept.
No. A row with a different column count than the rest is kept exactly as parsed and only flagged with a warning; the tool does not pad or trim columns to force alignment.
No. The on-page preview is capped to the first 8 rows and first 8 columns for readability; the cleaned output and any download include the full result.
Privacy build: This build removes ads, analytics, remote fonts, runtime CDN scripts, and file-operation telemetry. Selected files are processed in the browser using local JavaScript and browser APIs.
ConvertUnlimited does not provide a server-side upload endpoint for this CSV cleaning flow. Selected CSV files are processed locally in your browser.
ConvertUnlimited is provided as is. Review cleaned CSV before importing it into production systems.
Files are processed locally where supported. Review the Trust Center for the processing model and the Privacy Policy for public-site privacy boundaries.