CSV File Merger
Merge multiple CSV files into one.
Combining CSVs into one dataset
Data often arrives split across several CSV files — monthly exports, batches, files from different sources — that you need combined into a single dataset. This merges multiple CSVs into one, in your browser, so the data stays on your device.
Add your CSV files to merge them into one.
Merging cleanly, with matching columns
Merging CSVs is more than stacking files: the sensible approach keeps a single header row rather than repeating it from each file, and it works best when the files share the same columns in the same order, so the data lines up correctly. Files with mismatched columns are exactly where merges go wrong, producing misaligned or jumbled data, so it is worth checking the structures match before combining. Merging is a constant need in data work — consolidating periodic exports into one file for analysis, combining data gathered separately, or assembling a full dataset from pieces. Doing it in the browser keeps even sensitive data local, so records that should not be uploaded are combined on your own device. A clean merge into one properly-structured CSV turns a scattering of files into a single dataset ready to analyse, which is often the necessary first step before any real work with the data can begin.
Questions & answers
How should CSVs be merged cleanly?
Keeping a single header row rather than repeating it, and with files sharing the same columns in the same order so the data lines up correctly.
What goes wrong when merging CSVs?
Files with mismatched columns produce misaligned data, so it is worth checking the structures match before combining them.
Is my data uploaded?
No. The merging happens in your browser, so the data stays on your device.