How to Merge Multiple CSV Files Into One
Twelve monthly exports. Or one CSV per store, per region, per client. Each file has the same columns, and you need them stacked into a single file you can actually work with. Opening twelve files and copy-pasting them one under another is slow, and you'll redo it next month.
There's a cleaner way to merge multiple CSV files into one — and clean them all the same way in the same pass.
Why copy-paste (and most scripts) let you down
- Copy-paste is slow and risky. Miss a header row, paste into the wrong spot, and the whole file is off by one.
- Files drift. One export has an extra space in a header, another has a different date format — and your stacked file is quietly inconsistent.
- A Python script works once. Then a column moves, the path changes, and the non-coder on the team is stuck.
Two kinds of "merge" — know which you need
Stacking (append): same columns, more rows — twelve months into one year. That's what this guide covers.
Joining (by a key): pulling columns from a second file by matching an ID — the VLOOKUP job. That's a different step; see merge two spreadsheets without VLOOKUP.
The repeatable way, step by step
- Put all the files you want to combine in one folder.
- Build a cleaning recipe on a single sample file (trim, fix dates, dedupe — whatever they all need).
- Run the recipe in batch mode across the folder.
- Choose merge into one file as the output (instead of one cleaned file each).
- Export the single combined, cleaned file.
Do it with Kramata
Kramata is a free desktop app for repeatable spreadsheet cleanup. Build the recipe once on a sample, then point batch processing at the whole folder and choose merge into one. No code, no copy-paste, and your files never leave your computer.
- Same cleanup for every file — consistency by default.
- Separate outputs or merged — one cleaned file each, or all combined into one.
- Big folders, big files — powered by an in-process database, not formulas.
Cleaning a single file and saving recipes is free. Batch processing across a folder is part of Kramata Pro.
Related
Clean a messy CSV the same way every time · Merge two spreadsheets without VLOOKUP
FAQ
Do the files need identical columns? Same columns stack cleanly. Matching headers first (trim, fix case) keeps the merge tidy.
CSV and Excel mixed? Yes — Kramata reads both and combines them.
Is it reproducible next month? Yes — drop the new files in the folder and re-run the same recipe.