How do I mask part of a value in Excel, like showing only the last 4 digits?

Use a formula such as =REPT("*", LEN(A2)-4) & RIGHT(A2, 4) to hide everything but the last four characters. Tellsheet's Mask method does the same with adjustable keep-start and keep-end counts, and previews the result.

How can I anonymize data but keep the rows linkable?

Use a deterministic method — hashing or pseudonyms — so the same input always maps to the same token. Equal values stay equal, which means joins, counts, and pivots still work on the anonymized copy. Tellsheet's Hash and Pseudonymize methods are deterministic for exactly this reason.

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How to Anonymize & Mask Data in Excel

Sharing a spreadsheet for a demo, a report, or a support ticket? De-identify names, emails, and IDs first — by masking, hashing, redacting, or replacing them with consistent pseudonyms.

Last updated: August 2026

Original		Masked	Pseudonym
john.doe@acme.com	→	************e.com	ID 1
4539 8891 0032	→	*********0032	ID 2
Jane Smith	→	******mith	ID 3

Method 1 — Mask with a formula

Keep a few characters visible and star out the rest:

In a helper column, enter =REPT("*", LEN(A2)-4) & RIGHT(A2, 4) to keep only the last 4 characters.
To keep the start instead: =LEFT(A2, 2) & REPT("*", LEN(A2)-2).
Fill down, then Copy → Paste Special → Values over the original and delete the helper column.

Method 2 — Pseudonymize with a lookup

Build a small mapping table of each distinct value → a label (ID 1, ID 2…).
Use =VLOOKUP(A2, Map!$A:$B, 2, 0) (or XLOOKUP) to swap each value for its label.
Because the map is fixed, the same customer always becomes the same ID — so your counts and joins still line up.

Method 3 — Redact with Find & Replace

For quick, total removal, select the range and use Find & Replace (Ctrl+H) to overwrite values with a token like [REDACTED]. Simple, but it's all-or-nothing and not reversible.

The 1-click way — Tellsheet

Anonymize / Mask Data gives you all four methods without a single formula: Mask (keep N chars at the start/end), Hash (a stable 8-character token), Redact (a fixed placeholder), or Pseudonymize (Value → "ID 1"). The hash and pseudonym methods are deterministic — equal values map to equal tokens — so relationships in your data survive and pivots still work. Blanks and the header row are left alone, you preview before applying, and everything runs on your machine: no cells are ever uploaded.

Frequently asked questions

How do I show only the last 4 digits of a value?

Use =REPT("*", LEN(A2)-4) & RIGHT(A2, 4), or Tellsheet's Mask method with keep-end set to 4. Both hide everything but the last four characters.

How can I anonymize data but keep rows linkable?

Use a deterministic method — hashing or pseudonyms — so the same input always maps to the same token. Equal values stay equal, so joins, counts, and pivots still work on the anonymized copy.

Is it safe to anonymize sensitive data in Excel?

Cloud add-ins upload your cells to a server. Tellsheet runs entirely on your computer, so it's suitable for PII you can't paste into an online tool. Keep a secure copy of the originals if you still need them.

Can I find personal data before anonymizing it?

Yes — Tellsheet's Scan for PII tool flags likely emails, phone numbers, and IDs so you know which columns to mask first.

Related Excel guides

Anonymize a column in one click

Mask, hash, redact, or pseudonymize right inside Excel — with a preview, and nothing ever leaving your computer.

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