See what Excel might change before you open a file. Get an Excel workbook with every value stored as text, checked against your original CSV.
Synthetic samples. Your files are never needed for a demo.
Download original sample CSVPer file: 10 MiB · 100,000 data rows + header · 100 columns · 500,000 cells · 32,767 characters per cell. Whichever limit is reached first. Large files may take longer.
Choose a CSV or try a sample to start.
A successful decode does not prove the encoding is correct. Check names and punctuation yourself. Auto separator detection is an estimate. Override it if the preview is wrong.
Heuristics, not a complete prediction. Counts include the header; examples show up to 80 findings. A cell can have multiple findings.
All cells become text, including prices and dates. Convert numeric columns explicitly if you need calculations. Never overwrite your only original.
CSV only. Compares the same row and column, not IDs. Keep both files in the same order. Export always uses the original.
CSV Safe Open parses your original without numeric or date conversion. It flags common spreadsheet risks, writes every cell as text, then reads the XLSX back and checks the cell values and types. It cannot restore digits already lost, detect every incorrect encoding, or guarantee what another program does after you edit the result.
Read the testing policy