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Format guide · .xlsx

Anonymize an Excel workbook in your browser

Anonymize any document before it reaches an AI. Nothing leaves your device. Cell text and comments are replaced; formulas, number formats and charts stay exactly as they were.

  • 0 network requests
  • Works with Wi‑Fi off
  • Free, no account
  • Same format back

The tool below is preset for .xlsx files. Up to 10 files, 50 MB each.

  1. 1Upload
  2. 2Choose rule
  3. 3Review
  4. 4Download

Upload

Drop your XLSX file here or choose

Up to 10 files · 50 MB each · files stay on your device

  • xlsx

Old .doc, .ppt and .xls files: save them as .docx, .pptx or .xlsx first.

0 network requests during processing

What stays intact

What we preserve in Excel files

The file is edited in place: only the detected text changes. Everything else is written back byte for byte where possible.

  • Formulas untouched

    Formula cells are never rewritten. Only literal text in cells and the shared string table is scanned.

  • Sheets and structure

    All sheets are processed. Sheet names that contain a detected value, such as a client name, are replaced consistently.

  • Cell comments and notes

    Comment text is scanned and replaced like cell text.

  • Inline and shared strings

    Both storage forms are handled, so text pasted with formatting is not missed.

  • Number formats and column widths

    Formatting, freeze panes, filters and conditional formatting are copied unchanged.

  • Charts and pivot caches

    Chart parts are copied as they are. Pivot caches keep their data; refresh the pivot after anonymizing if it shows old labels.

What gets detected

Names, numbers and identifiers: three layers

Patterns with checksums (IBAN, national IDs, card numbers, emails, phones, URLs, IPs, dates, plates), your own dictionary of names and terms, and an optional model that runs in your browser for person, company and place names.

  • Person names
  • Companies and brands
  • Places and addresses
  • Emails and phone numbers
  • National IDs, tax IDs, passports
  • IBANs and card numbers
  • URLs and IP addresses
  • Dates and license plates
See how detection works

Questions

Excel questions, answered

Will formulas or numbers change?

No. Formulas and numeric cells are skipped. Only text cells and comments are scanned, so totals still compute.

Are all sheets processed?

Yes, every worksheet in the workbook, plus sheet names and comments.

What if a client name is used as a sheet name?

It is replaced with the same label used in the cells, for example Company A, and the mapping table records the pair.

Can it detect IBANs and ID numbers in cells?

Yes. IBANs, national IDs, tax IDs and card numbers are validated with their checksums, which keeps false positives low.

Does it handle very large workbooks?

Files up to 50 MB are supported. Large workbooks take longer because the shared string table is scanned once and rewritten.

Are .xls or .csv files supported?

.xls is not; save it as .xlsx first. CSV has its own page and is handled cell by cell.

Other formats

Same tool, eight more file types

Drop any of these into the tool above; the format is detected from the file, so you never have to switch pages.