Vertical Append Stack & Horizontal Key Join • Zero Uploads
Merge Multiple CSV Files Online
Import your first CSV or workbook, click + Add Sheet to drop additional CSV files as tabs, then run Merge / Join Sheets to either Append Rows Vertically or match records by key column.
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Drop XLSX, CSV, TSV, Markdown (.md), or JSON here
Runs locally inside browser memory. Multi-sheet workbooks open into tabs automatically.
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Zero Uploads
Combine Two or More Columns
Merge 2+ columns cleanly without writing formulas.
Preview
Split Column by Delimiter
Remove Duplicate Rows
Find & Replace
Sort Rows
Filter or Delete Matching Rows
Quick Cleanup:
Fill, Prefix / Suffix & Extract Column
Merge Multiple Files / VLOOKUP Join Sheets
Append rows from multiple files/tabs or join two sheets by a key column.
Option A: Stack / Append All Open Sheet Tabs
Option B: VLOOKUP / Left-Join Two Sheets by Key
Format Preview & Export Converter
Column Profiler & Quick Summary
| Col | Header | Filled | Blank | Unique | Dupes | Min / Max / Avg |
|---|
Paste CSV, TSV, Markdown Table, JSON, or HTML
Confirm Action
Two Ways to Merge CSVs in One Click
- Stack / Append CSV Files: Combine monthly exports or lead lists vertically while keeping headers aligned.
- Join / Enrich by ID (Left Join): Match emails, SKUs, or order numbers across two CSV files without writing VLOOKUP or Python pandas scripts.
- Deduplicate Immediately: Run Remove Duplicates on the combined sheet before exporting clean XLSX or CSV.