Merge two lists and kill the duplicates, exactly
Combining two exports or cleaning a contact list sounds simple until you hit the duplicates: the same person twice, or 'Jon Smith' and 'John Smith' who are really one contact. This free tool merges your lists and removes both exact and near-duplicate rows, shows you exactly what it did, and gives you a clean CSV back, all in your browser.
What it does
- Merge two lists into one, or clean a single list.
- Match on any column (like Email) or the whole row.
- Exact and fuzzy matching: fuzzy catches near-duplicates such as typos, extra spaces and small name variations.
- Full preview: see every duplicate group, which row was kept and which were removed.
- Export the cleaned list as a CSV or copy it.
Why a real tool beats pasting into a chatbot
Data hygiene has to be exact. Chat models quietly truncate long lists and can drop or invent rows, so you never quite trust the output, and for a contact or product list that is dangerous. This tool processes every row deterministically, never truncates, and shows you a preview of exactly what it removed. Because it runs in your browser, your customer data never leaves your device, which most online dedupe tools cannot promise.
Exact versus fuzzy
Use exact matching on fields that should be identical, like an email address or an ID: two rows are duplicates only if that value matches character for character. Use fuzzy matching on messy human-entered fields like names and addresses, where the same person is written slightly differently each time. The strictness slider controls how close two entries must be before they are merged, so you can be aggressive on obvious typos or conservative to avoid merging genuinely different people.
Private and free
Everything runs in your browser: parsing, matching and export. Nothing is uploaded. It is free and unlimited within your browser's memory, and handles standard comma-separated values with quoted fields.