Smart CSV Merger

Overview

Merge multiple CSV spreadsheets into a single unified file directly in your browser. Unlike naive mergers that just concatenate text and break when column orders don't match, Smart CSV Merger parses each file's structure, aligns columns by header name, fills missing fields, and combines your dataset cleanly.

How to Use

1. Upload your CSV files (select multiple files at once or drop them together).
2. Choose options:
   • Add Source File Column: Inserts a _source_file column showing where each row came from.
   • Deduplicate Rows: Automatically skips identical rows across files.
3. Click Merge CSV Files.
4. Download your combined CSV and inspect the merged column breakdown.

Key Features

• Header Alignment: Automatically maps columns by name even if files have columns in different orders.
• Header Union: Combines all unique column headers across all files; missing values for a file are filled with blank entries.
• 100% Client-Side Privacy: Your data never leaves your computer. Works securely with sensitive customer, payroll, or business data.
• Detailed Summary: View row counts, duplicate statistics, and column mappings in a clean summary table.

Common Use Cases

• Monthly/Quarterly Reports: Combining identical reports exported from different branches or periods.
• Data Pipeline Preparation: Merging disparate dumps with overlapping schemas into a single normalized file.
• E-commerce & Inventory: Consolidating stock lists from multiple vendors.

Frequently Asked Questions

What happens if CSV files have different columns?

The tool takes the union of all column headers. If File A has Name, Email and File B has Email, Phone, the output will have Name, Email, Phone, with empty values where data didn't exist.

Are my spreadsheets uploaded to any server?

No. All parsing and merging occurs entirely within your browser using Web Workers and JavaScript.