Browser Tool
Free CSV Combiner
Merge dozens of files instantly. We auto-align headers and add a traceability column so you never lose track of your data source.100% Client-Side. Secure processing.
Upload CSV files
Drag and drop multiple files here. We'll verify headers and combine them automatically.
Use Case
Consolidate Multiple Files
Merge monthly reports or identical extracts into a single file instantly. Useful for preparing batches for analysis when source files are consistent.
- Multi-file concatenation
- Auto-align headers
- Add source filename column
Need to clean or validate the merged data?
Simple concatenation works if files are perfect. DataFlowMapper allows you to map, transform, and validate the combined dataset in a repeatable workflow before export.
Client-Side Processing ArchitectureSecure
Your data never leaves your device. All processing happens locally in your browser's memory via WebAssembly/JavaScript. This ensures complete data sovereignty and compliance with GDPR, HIPAA, and SOC2 standards as no files are uploaded to our servers.
Frequently Asked Questions
What is the difference between Combining and Merging?▼
Combining (or Appending) stacks files vertically to create a longer list of rows. Merging (or Joining) links files horizontally based on a common ID column. Use this tool if you have multiple monthly reports you want to combine into one master file.
Do headers need to match exactly?▼
Ideally, yes. However, our tool attempts to align columns by name. If File A has 'Email' and File B has 'Email Address', they might end up in separate columns unless you standardize headers first.
How many files can I combine?▼
You can select hundreds of files at once. The practical limit is your browser's memory, but users regularly combine batches of 50+ files instantly.
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