How to clean a CSV file
CSV files are easy to create and easy to get wrong. Exports from different systems disagree about dates, spaces, blanks and capitalisation, and the problems only show up when you try to analyse the file. Omixa checks the file, fixes what is safe to fix, and flags the rest for you to decide.
Clean a file freeCSV, XLSX or XLS · no account needed
What goes wrong in CSV files
Most CSV problems are small but numerous: values padded with spaces, the same category written three ways (Male, MALE, male), dates in several formats, phone numbers with mixed punctuation, and "N/A", "null" or "-" standing in for a missing value. Exact duplicate rows are common when files are merged or exported twice.
None of these stop a CSV from opening, which is why they survive until a pivot table, a join or a chart gives the wrong answer.
What Omixa does with a CSV
Upload a .csv file (up to 10 MB on Free, 25 MB with Pro) and Omixa reads it cell by cell. It reports what it found with a data-quality score, applies the safe fixes you leave switched on, and gives you a before and after preview and a change log.
Only a truly empty cell is treated as missing when the file is read. Values such as N/A, null and NA are recognised as placeholders by a rule you can see, so each conversion is logged rather than happening silently. Whole numbers stay whole (45 does not become 45.0), and ID-like columns such as account numbers and zip codes are protected from changes that would drop leading zeros.
Your original stays untouched
Omixa never edits the file you uploaded. It writes a separate cleaned copy, and then re-reads that copy to check it against the cleaned data. Cells nobody changed read exactly as they did in your upload. Files are deleted automatically, at most 30 minutes after upload.
Steps
- Upload your CSV, or try one of the sample files.
- Read the findings and the quality score.
- Choose which cleaning rules to apply and review any flagged values.
- Download the cleaned CSV and keep the change log with it.
Common questions
Is it free to clean a CSV file with Omixa?
Yes. Cleaning one file at a time is free and needs no account. Omixa Pro adds batch processing, Quality Profiles and PDF quality reports.
Will Omixa change my data without asking?
Only safe, well-defined fixes are applied by default. Filling gaps with estimates is off unless you turn it on, and anything ambiguous is flagged for your review.
What happens to my file after cleaning?
It is removed automatically, at most 30 minutes after upload. Omixa keeps basic records such as file name, size, row counts and quality scores, not your cell contents.
Related guides
- Remove duplicate rowsFind and remove exact duplicate rows in CSV and Excel files, and review near-duplicates safely. The first occurrence is kept and every removal is logged.
- Handle missing valuesSpot blanks and placeholders like N/A, null and dashes, and decide whether to leave them or fill them. Omixa never fills gaps with estimates unless you ask.
- Standardize spreadsheet dataMake spreadsheet values consistent: dates, phone numbers, emails, countries, categories and capitalisation. Ambiguous values are flagged, not guessed.