CSVCLEAN / A SMALL TOOL FOR TIDIER DATA
Clean the cells.
Keep the control.
Choose exactly what changes, inspect every duplicate group, and download a new copy. Your original CSV never changes.
UTF-8 CSV · up to 5 MiB, 5,000 records, 100 columns · No account. No charge. No uploads.
Open a CSV or explore the synthetic sample.
No source loaded.
Set column rules
Nothing changes until you preview.
Order: trim → case → literal replacement → date. No type or locale guessing. Blank dates remain blank. Rules never alter the header.
All configured columns
Choose duplicate keys
Exact matches after your selected rules.
Select no columns to keep every record. A blank component excludes a record from grouping; it is always retained. Whitespace is significant unless you trim that column.
Every preview starts from the original source. Applying twice cannot compound a replacement. Editing rules clears the preview and its approval.
Fix these before exporting
Review the exact result
Before → after
Each entry names the original CSV record (header = record 1), not a physical line. Quoted newlines stay in their record. Before/after values use JSON string notation to make whitespace and line breaks visible. All changes are available across pages and in the audit JSON.
| Record | Column | Before | After |
|---|
Keep selections
Every duplicate starts retained. Uncheck only the records you want omitted from the new copy. At least one record per group must remain. The full source and transformed record values are shown below.
| Keep | Original record | Original values (ordered JSON array) | Transformed values |
|---|
CSV formula-like values (including headers and negative-looking text) receive a leading apostrophe. Audit/project JSON preserve exact text. Import CSV columns as Text in spreadsheet software to prevent leading-zero or date auto-conversion. Review downloads before use; local JSON is unencrypted.
Record explorer
All columns are preserved, including empty and duplicate headers. Position numbers disambiguate them. Scroll horizontally for wide data; every record is available across pages.
Local by design. Explicit by default.
Your work lives in this tab until you save a project. Closing or resetting clears the session, not your source files or earlier downloads. There is no auto-save. No uploads, app analytics, fuzzy matching, XLSX support or inferred data types. Use a current desktop browser. Large files can temporarily block the page; low-memory devices may need smaller files. Project and audit exports contain your data and are not encrypted—keep them private.