Dedupe
To remove duplicates from a CSV or mailing list: open the file in Sift, pick a match key (email, phone, or a name and company fingerprint), choose exact or fuzzy matching, review the duplicate clusters with a before and after diff, and merge each into one record. Then export a clean file. It's free, it runs entirely in your browser, and nothing is uploaded.
Dedupe your CSV in Sift, free →
Excel and Google Sheets both have a built-in way to strip duplicate rows, and for a truly clean list they work. In Excel it's Data → Remove Duplicates: pick the columns to compare on, and it deletes any row that repeats. In Google Sheets the equivalent is =UNIQUE(range), which returns only the distinct rows.
Both share the same two limits. First, they only catch exact, character-for-character matches. The duplicates that actually pollute a mailing list are rarely exact: the same person shows up as "Bob" and "Robert", as "Jon Smith" and "Jonathan Smith" on the same phone number, and the same email in two different casings. Exact-match dedupe keeps every one of them. As one CRM admin described the manual approach on Reddit, companies handle dedupe "with Excel and building formulas... you are going to end up missing quite a few if you use Excel."
Second, when they do find a duplicate, they delete the duplicate row. If one row has the phone number and the other has the job title, you lose whichever row Excel drops. There's no merging two half-complete rows into a single, more-complete record.
Not every list needs fuzzy matching or survivorship. Reach for Excel's Remove Duplicates or Google Sheets UNIQUE when:
Once the duplicates are near-matches, or two rows each hold a field you want to keep, an exact-match tool stops short. That's the point where fuzzy dedupe and golden-record merging earn their place.