CSVTools.dev

CSV Merge

Combine multiple CSV files into a single file. Handles different column orders and missing fields automatically.

100% Private — Files stay in your browserInstant processing

Drop CSV files here to add them

Supports .csv files. Add as many as you need.

How to csv merge

  1. Upload multiple CSV files you want to merge.
  2. The file will be processed instantly in your browser — no server upload required.
  3. Preview the result in the data table below.
  4. Click "Download" to save the output file to your device.

CSVTools.dev provides free online tools for working with CSV and JSON data. All processing happens locally in your browser, ensuring your data remains completely private and secure. No registration required.