How to Split a Large CSV
- Choose or drag in the CSV file. It is not uploaded, so even a multi-gigabyte file is ready in a second.
- Choose how to split: rows per file (best for Excel), maximum size (best for upload forms and email limits) or number of files (best for sharing work out between people or machines).
- Press Split File. Parts are named
yourfile-part-001.csv,yourfile-part-002.csvand so on. - Download all parts as a ZIP or save them straight into a folder.
Which Split Mode to Use
| You want to… | Use | Suggested setting |
|---|---|---|
| Open the data in Excel | Rows per file | 1,000,000 |
| Open it in Google Sheets | Rows per file | 10,000,000 ÷ number of columns |
| Import into a tool with an upload limit | Maximum size | A little under the limit, e.g. 95 MB for 100 MB |
| Attach to an email | Maximum size | 20 MB (or ZIP each part) |
| Divide work between 4 people | Number of files | 4 |
Why Excel Says the File Is Too Large
An Excel worksheet has a hard limit of 1,048,576 rows and 16,384 columns. When a CSV has more rows, Excel loads the first 1,048,576 and shows a warning that the file was not loaded completely. Everything after that row is simply missing, and if you save the file, it is gone for good. Well before that limit, a file of several hundred megabytes can make Excel slow or stop responding, because Excel works out cell types and formatting for every value.
Splitting the CSV into parts under the limit is the simplest fix when you need to look at, clean or share the data in a spreadsheet. If you only need a subset — one region, one customer, one month — splitting by column value usually gives you smaller, more useful files.
What Makes This Different from Other CSV Splitters
Upload-based splitters have to receive your whole file first and typically charge for large ones. Browser-based splitters that load the entire file into memory fail on big files, often without a clear error. This tool reads the file in small chunks and writes each part to your disk as it goes, so a 10 GB file uses about as much memory as a 10 MB one. It understands quoted values with commas and line breaks, keeps your values exactly as they are, and never sends your data anywhere.
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