Duplicate rows creep into spreadsheets from repeated exports, merged lists, or manual data entry, and they throw off counts and totals. InstantTools Deduplicate Rows removes exact duplicate rows entirely in your browser using the SheetJS engine, so your file never gets uploaded.
What this tool actually does
Upload a .xlsx, .xls, or .csv file and this tool compares every row across all columns — a row is only removed if it's an exact match of another row, cell for cell. There's no option to deduplicate based on a single column (like just "Email" while ignoring other differing fields); if two rows share the same email but differ anywhere else, both are kept.
One more thing worth knowing: only the first sheet of a multi-tab workbook is processed. If your file has several tabs, upload each one separately (or split it first with our Split Sheet tool) if you need every tab deduplicated. The result always downloads as .xlsx, regardless of whether you uploaded a .csv.
Why do this locally instead of uploading?
Most online "duplicate removers" require uploading your file to their servers — a real exposure for customer lists, payroll data, or CRM exports. Because deduplication runs entirely in your browser's memory, nothing leaves your device.
How to remove duplicates
- Drag and drop your Excel or CSV file into the uploader.
- Click "Run & Download."
- The engine compares every row for an exact match and keeps only the first occurrence of each unique row.
- Your cleaned
.xlsxfile downloads automatically.
Common use cases
- Clean a mailing list that was assembled from several exports before importing it into an email tool.
- Remove accidental double-entries from an expense log or sales report.
- Deduplicate a contact list before a CRM import, when you know the source data is truly identical row-for-row.
Frequently Asked Questions
Can I deduplicate based on just one column, like Email?
Not today — this tool only removes rows that are identical across every column. If your rows differ in any field besides the key column you care about (a typo, a different timestamp, etc.), they won't be treated as duplicates.
Does it process every tab in my workbook?
No — only the first sheet. If you have a multi-tab file, split it into separate files first with our Split Sheet tool, then run each one through this tool individually.
Does this tool send any data to a server?
No. The entire deduplication process happens in your browser's memory using SheetJS. Nothing is uploaded.
Will the formatting of my original file be preserved?
The output always exports as .xlsx, and cell values are preserved. Complex formatting, formulas, and macros from the original file are not carried over — the output is a clean re-export of the deduplicated data, not a formatted copy.
Is there a file size limit?
Free accounts can process files up to 100MB. Premium accounts can handle files up to 500MB, still entirely in the browser.