Output files have uneven row counts
The row count setting applies to data rows, while the header row is copied into every file.
Set the split size based on the destination upload limit and remember that each file will include one extra header row.
Use this tool
Prepare the input and run the tool
Paste CSV text or choose a .csv file. Result: Download one or more smaller CSV files.
Split a local CSV into smaller files by data-row count. Large files are streamed in a Web Worker so the page stays responsive.
Recommended laneUp to 500MB on modern desktop browsers
Local splitNo upload; CSV files stream in a worker
Large outputsSplit files are downloaded as safe CSV parts
Best for Chrome or Edge on a desktop browser. Keep this tab open while the worker runs. For very large files, choose a larger row count such as 100,000 rows per file to avoid producing too many parts.
Drop a CSV file here
Use this before running another tool when one source file is too large for the recommended browser lane.
Ready.
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Split CSV output summary appears here.
Data handling: Files and pasted data are processed in this browser session.
Tool guide
How to use Split CSV
Use this when an upload form, email, review process, or another browser-local tool cannot handle one large CSV. The header row is copied into each split file.
What this tool does
Split a large CSV into smaller CSV files by row count in a local browser worker.
- Input
- Paste CSV text or choose a .csv file
- Output
- Download one or more smaller CSV files
Tool advantages
- Runs in this page; the file or pasted data is not sent to a new app.
- Keeps the preview, report, and download in the same screen.
- Gives you a report you can use as a cleanup list.
Step-by-step usage guide
- 1Choose a local CSV file or paste a small sample.
- 2Set the number of data rows per file.
- 3Run the local worker and download the split CSV files.
Common errors and fixes
A downstream import says headers are missing
The original CSV may not have a real header row, or the first row may contain data.
Add the correct header row before splitting so every output file carries the expected column names.
Large CSV text feels slow to preview
Very large pasted files can stress the browser tab before the ZIP is created.
Use a smaller row size, close other heavy tabs, or split the source file in smaller batches.
When to use Split CSV
- You are checking files before an upload, import, share, or delivery.
- You want to confirm the result before sending it to another system.
- You need a copied result, downloaded file, or report that can be reviewed outside the page.
FAQ
Is the header kept?
Yes. The first CSV row is included as the header in each split file.
How are rows counted?
The row limit applies to data rows after the header.
Can it handle very large files?
The recommended lane is up to 500MB on modern desktop Chrome or Edge. The file is streamed locally in a worker and is not uploaded.