CSV & Excel Cleaner
Clean rows in CSV or Excel
Open one CSV or XLSX file, or paste CSV below. Files are processed in your browser. Limits: 5 MB, 10,000 rows, 100 columns, 200,000 cells.
Open a file or load pasted CSV to see your rows.
Cleaned preview
Edit any visible cell to correct its source value. Preview and downloads update after each edit. Use the page buttons to reach more rows.
Downloads contain only the selected sheet's values. Excel formulas use their stored results; formatting, charts, and macros are not retained. XLSX text cells are exported as text.
About CSV & Excel Cleaner
CSV & Excel Cleaner applies a small set of explicit cleanup rules to a table: trim surrounding spaces, remove empty rows, normalize a selected date column, and remove duplicates. Open a CSV or XLSX file, or paste CSV, then inspect the editable preview before downloading the cleaned values. For a workbook, you choose one sheet to process. The tool runs in your browser and creates a separate CSV or XLSX download. It is useful for preparing an import table when you know which fields identify a record and how its dates are written.
How to Use CSV & Excel Cleaner
Load the table and choose its separator
Open one CSV or XLSX file up to 5 MB, or paste CSV and click Load pasted CSV. Select comma, semicolon, or tab for CSV input. For XLSX, choose the sheet you want to clean. A table may contain up to 10,000 rows including its header, 100 columns, and 200,000 cells including blank positions.
Set the header and cleanup rules
Keep First row is a header checked when the first row names your columns. Enable Trim strings to remove surrounding whitespace, and Remove empty rows when needed. Choose whether duplicates should compare all columns or one selected column. Select a date column and its explicit input format only when you want date normalization.
Review changes and correct cells
The preview updates when a cleanup option changes, and the status reports removed rows, trimmed cells, normalized dates, and unrecognized dates. Use the row paging controls to inspect more of the table. Edit a visible cell to correct its source value, then leave the cell to apply the cleanup rules again and refresh the result.
Download the cleaned values
Choose Download cleaned CSV or Download cleaned XLSX after checking the preview. CSV protection for formula-like values starts enabled and can be changed before export. Downloads contain the selected sheet values rather than the original workbook structure. Keep the source file if you need its other sheets, formulas, formatting, or charts later.
Common Use Cases
Prepare a contact or product import
Remove surrounding spaces from identifiers and compare one column when that field defines a duplicate in the destination system. Check blank keys first: blank values in the selected column also count as duplicates. Comparing every column is more conservative when two records share an identifier but have different details. Use Online Spreadsheet for broader table editing or calculations.
Standardize dates before data conversion
Choose day/month/year or month/day/year based on the source system, then export recognized dates as YYYY-MM-DD. An ambiguous value such as 03/04/2026 means different dates under those two choices. Review the source convention before changing it. If your next step needs structured data instead of a spreadsheet, SQL Converter can work with a checked CSV export.
Technical Specifications
| Input Formats | CSV, XLSX, Pasted CSV |
|---|---|
| Output Formats | CSV, XLSX |
| File Size Limit | 5 MB |
| Processing Engine | 100% Client-side (Runs locally in your browser) |
| Data Retention | Files never leave your device |
| Batch Processing | Single file processing |
Tips for Best Results
Cleanup runs in this order: trim strings, remove empty rows, normalize dates, then deduplicate. Earlier changes affect duplicate comparisons. For example, two keys that differ only by surrounding spaces can match after trimming.
Trim strings removes whitespace at the beginning and end of text. It does not rewrite capitalization, punctuation, or spaces inside a product name. Duplicate comparisons remain case-sensitive.
A checked header is retained outside the data-row removal and date rules. If the source has no header, uncheck the option so the first record participates in cleanup instead of being protected as column names.
Choose the separator that matches the CSV source. If the table appears in one column, try the appropriate separator before making cleanup decisions. Changing the separator reloads the CSV data.
Frequently Asked Questions
Which duplicate row is kept?
The first row encountered with a matching comparison value is retained. Later matches are removed. Choose Compare all columns for identical full rows, or a named column for a key such as SKU. The tool does not merge information from the removed rows into the retained record.
Are ABC and abc treated as the same duplicate key?
No. Comparisons are case-sensitive. Trimming can remove surrounding spaces when enabled, but it does not convert letter case. If your destination treats those identifiers as equivalent, standardize them deliberately in a spreadsheet editor before relying on duplicate removal.
What happens to blank values in the duplicate column?
When you compare one column, repeated blank values match each other and only the first such record remains. A row with a blank key can still contain useful information elsewhere. Inspect those records before enabling single-column duplicate removal so you do not discard distinct entries unintentionally.
Will the cleaner guess an unfamiliar date format?
No. You select YYYY-MM-DD, DD/MM/YYYY or DD-MM-YYYY, or MM/DD/YYYY or MM-DD-YYYY. Recognized valid dates become YYYY-MM-DD. Unrecognized values and impossible dates remain unchanged and contribute to the unrecognized-date count. It does not guess month names, two-digit years, or mixed regional conventions.
Does XLSX export preserve formulas and other sheets?
No. The cleaner reads the selected sheet values and exports a new table. Existing formulas use their stored results rather than being recalculated here. Other sheets, cell formatting, charts, and macros are not retained. Keep the workbook original when any of that information matters.
Why does a CSV value start with an apostrophe after export?
With CSV protection enabled, text starting with formula-like characters such as equals, plus, minus, or at-sign receives an apostrophe. This reduces the chance of a spreadsheet treating that text as a formula. You can disable the option when your destination requires the literal value and you have checked the data.
Do I need to click a separate cleanup button?
After data is loaded, changing an option updates the cleaned preview automatically. A cell edit applies when you leave that cell. Editing pasted CSV is different: click Load pasted CSV again to replace the loaded table with the revised text. Download after the current preview has updated.