Clean a CSV File Online
CSV exports can collect stray spaces, completely blank records, repeated rows, or columns that were never filled in. This CSV Cleaner lets you choose which of those issues to fix, review the result, and download a cleaned copy. It works with CSV and TSV files up to 50 MB, and leaves your original file untouched.
The first row is treated as the header. After opening a file, the page shows a preview of the source data. Select the cleanup options you need and choose Clean CSV to apply them.
How to Clean a CSV or TSV File
- Choose Browse CSV File or drop a CSV or TSV file into the upload area.
- Review the source preview and choose the cleanup options you want.
- Select Clean CSV to process the data. The page shows the cleaned preview and counts for rows and columns removed.
- Check the result, then choose Download Cleaned CSV to save a separate file.
Use only the cleanup steps you need. Trimming, blank-row removal, and duplicate-row removal are selected by default; removing empty columns is optional. Trimming runs first, so it can affect whether a row counts as blank or duplicate.
What Each CSV Cleaning Option Does
| Option | What it changes |
|---|---|
| Trim cell whitespace | Removes leading and trailing whitespace from the header cells and data values. Trimming runs before the other selected cleanup steps. |
| Remove blank rows | Removes data rows where every cell is empty or contains only whitespace. The header row is kept. |
| Remove duplicate rows | Keeps the first occurrence of a complete data row and removes later identical rows. It compares every cell in the row, not one chosen column. |
| Remove empty columns | Removes columns with no non-whitespace data when at least one column contains values. If all data columns are empty, the tool keeps the headings so the output retains a table structure. |
How Duplicate Row Removal Works
The cleaner compares whole rows after any selected trimming. Every value must match for a row to count as a duplicate, and letter case matters: London and london are different values. When two rows match, the first stays in the cleaned file and later copies are removed.
This works when the entire record must be repeated to count as a duplicate. If you want to deduplicate by one field, such as an email address or SKU, use a workflow that lets you choose a key column; this cleaner compares all columns together.
Review and Download the Cleaned File
After cleanup, the summary reports the number of rows before and after, duplicate rows removed, blank rows removed, and empty columns removed. The table below previews up to 10 cleaned rows at a time; use the page arrows to browse the rest. Review the headings and sample rows before downloading.
Download Cleaned CSV saves a new comma-separated .csv file. If you opened a TSV file, the output is still CSV. CSV stores text values; it does not preserve spreadsheet formatting, formulas, or multiple worksheets. The original upload is not overwritten.
Questions About Cleaning CSV Files
Can I remove duplicates based on one column?
No. This cleaner compares complete rows and keeps the first exact match. It does not let you choose a key column, and values with different letter case are treated as different.
Does trimming happen before duplicate checking?
Yes. When Trim cell whitespace is selected, surrounding whitespace is removed first. Rows that then have the same values across every column are treated as duplicates.
Will removing blank rows delete my header?
No. The first row is treated as the header and is kept. The blank-row option applies to the data rows that follow it.
Can I clean a TSV file?
Yes. You can open CSV and TSV files up to 50 MB. The cleaned download is saved as a comma-separated CSV file.
Does the cleaner change my original file?
No. Cleanup happens in the page, and the download is a separate file. Your source file is not overwritten.
Are my file contents uploaded?
No. The selected file is read and processed in your browser. This tool does not send its contents to a server.
File Handling and CSV Limits
The cleaner reads the selected file in your browser and supports files up to 50 MB. Processing time depends on the size of the file and the available memory and speed of your device. If the file has malformed or inconsistent rows, check its structure with the CSV Validator before cleaning.
Related CSV Tools
Use the CSV Row Viewer to find and inspect individual records, the CSV Column Viewer to focus on one field, or the CSV Editor to change cells manually. Browse all CSV tools for other tasks.