How to Use the CSV Splitter Tool
✂️ Open the CSV Splitter and follow along with this tutorial.
Open Tool →Steps
Step 1: Prepare Your CSV File
Locate the CSV file you want to split on your device. Make sure it has a header row as the first row — the tool will preserve this header in every output file.
Step 2: Open the CSV Splitter
Navigate to financialdatatools.com/csv-tools/csv-splitter/ in any modern browser. No login or installation is required.
Step 3: Upload Your CSV
Click Upload CSV in the toolbar or drag and drop your file onto the drop zone. The tool parses the file and shows statistics: filename, total row count, and column count.
Step 4: Choose a Split Mode
In the options bar, select one of two modes:
- Split by row count — each output file will contain at most N data rows (plus the header). The number of output files is calculated automatically.
- Split by file count — produce exactly N output files with rows divided as evenly as possible.
Step 5: Enter the Split Value
Type the desired row count or file count into the input field. A preview shows how many output files will be created and the approximate rows per file.
Step 6: Run the Split
Click Split. The tool divides the data rows into groups and shows the output file list immediately. All processing happens in your browser.
Step 7: Review Output Files
Each output file is listed with its filename and row count. Confirm the counts add up to your original total row count.
Step 8: Download the Files
Click Download on each file card to save it as a .csv file. Every file includes the original header row followed by its assigned data rows.
Privacy reminder: Your file is never uploaded anywhere. All splitting happens locally in your browser tab. Closing the tab clears all data immediately.
Common Issues
- File count of 1: If you set a row count higher than the file's total rows, you will get one output file identical to the input. Lower the row count.
- Uneven last file: When splitting by row count, the last file will often have fewer rows than the others. This is normal — it contains the remaining rows.
- No header in output: The tool always writes the first row of the input as the header of every output. If your source CSV has no header, add one before splitting.