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CSV Column Arithmetic
Append exact add, subtract or multiply results from two CSV columns, with up to twelve product fraction digits.
UTF-8 CSV or TSV file, Pasted delimited text
Quoted delimited CSV
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Paste CSV input or choose a CSV file and select Input delimiter.
- Set Left column, Right column, Operation and New column name. Choose Protect spreadsheet formulas.
- Select Calculate column, then Download result for calculated-column.csv. Cancel stops the worker; Reset restores defaults.
Examples
Multiplying 0.000001 by 0.000001 produces 0.000000000001 exactly; adding-1.25 and 2 produces 0.75.
Limitations
- 5 MiB input,50000 data rows,500 output columns,500000 cells including header,20 MiB output and 30 seconds.
- Each operand needs an optional sign,1–18 digits total and at most 6 fraction digits; no spaces, exponents or locale separators. Multiplication uses scale12 and at most 48 scaled-product digits.
- Only generated results normalize signed zero/trailing fraction zeros. Generated valid negative decimal text is not prefixed by spreadsheet protection; untrusted originals/header follow the existing policy exactly once.
- No division, rounding, formulas or arbitrary expressions. Headers must remain unique after protection.
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