CSV injection sanitizer
Make a CSV safe to open in Excel or Google Sheets by neutralising cells that would otherwise run as formulas.
- Nothing uploaded
- Instant results
- No account needed
Drop a CSV file hereUp to 10 MB · processed in this tab, never uploaded
Your result appears here as soon as you add a file.
How it works
Three steps, nothing to install- 01
Add the CSV you’re about to share or open.
- 02
Choose the prefix (an apostrophe or a tab) and whether plain numbers like -5 are left alone.
- 03
Download the sanitised file.
Good to know
What the tool does, exactlyWhat CSV injection is
Spreadsheet apps treat a cell that begins with =, +, - or @ as a formula. If a CSV contains values typed by other people, such as form responses or support tickets, opening it can run formulas the author never intended. OWASP recommends prefixing those cells so they are shown as text.
Apostrophe or tab?
An apostrophe is the conventional way to force text in a spreadsheet and is hidden in Excel’s cell display. A tab is invisible in most apps and is what the CleanYourDataset workspace uses on export. Either way, plain numbers such as -5 can be left as numbers.
Private by design
The file is processed in your browser and never uploaded, so it’s safe for customer lists and financial exports.
Questions
About formula sanitizerWill negative numbers break?
Not with “Leave plain numbers alone” on: values such as -5, +3.2 or -1,000.50 stay as they are. Turn it off to prefix every cell that starts with a formula character.
Is the header row changed?
No. Only data rows are sanitised when “First row is a header” is on.
Can I undo it later?
Yes. The prefix is a single leading character, so it can be removed with a find-and-replace if you ever need the original value.
Keep going
All free toolsCleaning the same
files every week?
The free workspace saves each dataset, with undo and a full history. See features