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For Spreadsheets

Bulk Percentage Calculator

Upload a CSV, apply a percentage operation to thousands of rows in one click, download the result. Files never leave your browser.

Upload CSV

Tip: All processing happens locally in your browser using JavaScript. The CSV file is never sent to a server, so even sensitive data is safe.

How it works

Upload any spreadsheet exported as CSV (Excel: File → Save As → CSV; Google Sheets: File → Download → CSV). One column should contain the numbers you want to operate on.

  1. Drag your CSV onto the upload zone — it never leaves your browser.
  2. Tell us which column the numbers live in and pick an operation (e.g. add 20% VAT, take 15% off, compute % change against another column).
  3. Hit Run. A preview appears, then download the result with a new column appended.

Example

Adding 20% VAT to the "price" column would produce:

Input CSV
product,price
Mug,12.00
T-shirt,25.50
Hoodie,49.00
Result CSV
product,price,price_with_vat
Mug,12.00,14.40
T-shirt,25.50,30.60
Hoodie,49.00,58.80