Clean a CSV File Online
Fix the formatting, duplicates and stray spaces automatically.
Drop a CSV file here
or browse your computer
.csv, .tsv · Up to 10MB and 50,000 rows without an account.
By uploading you agree to our Terms and Privacy Policy. Files are deleted automatically.
Free to run and free to preview. Downloading the finished file is part of the paid product.
How it works
- 1Upload your file. All of it is processed, not a sample.
- 2We tell you in plain English what is wrong with it — how many duplicates, how many date formats, which columns have stray spaces.
- 3You tick the fixes you want. Anything that could lose data arrives unticked.
- 4We process the whole file and show you a before-and-after preview with every changed cell marked and explained.
When people use this
- —An export from a system that formats dates three different ways
- —A contact list with duplicate records and inconsistent capitalisation
- —A file where a column will not add up because the numbers are stored as text
- —A CSV that opens with strange characters where the accents should be
Supported formats
This tool accepts .csv, .tsv. Up to 10MB and 50,000 rows without an account. We work out the encoding and the separator from the file itself, so a semicolon-separated export or one saved in a non-UTF-8 encoding opens correctly rather than as a single column of nonsense.
Questions
- What does it actually fix?
- Duplicate rows, blank rows and columns, stray and invisible whitespace, inconsistent capitalisation, mixed date formats, currency and percentage formatting, phone number formats, and numbers stored as text. It also finds problems it will not fix automatically — malformed email addresses, rows with the wrong number of columns — and tells you about those instead.
- What if it gets something wrong?
- It will not guess. Anything we cannot transform confidently keeps its original value and goes into a Needs Review sheet with the reason, and the workbook includes a Change Log listing every transformation and how many cells it touched. You can see exactly what happened.
- Do I need an account?
- Not to upload, not to process and not to see the result. Downloading the cleaned file is where we ask — either a one-off payment for that file, or a subscription if you do this regularly.
- What happens to my file?
- It is uploaded over an encrypted connection, processed, and deleted automatically - within 24 hours for anonymous use. We never use anyone’s spreadsheet data to train models. You can delete a job and its files at any time from the job page.
Do this every month? Save the cleanup and re-run it in two clicks.
The full app handles jobs that need several steps across several files, and can save the whole thing so next month takes two clicks.
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