Some constraints aren't about row count at all, they're about file size: an upload portal that rejects files over a certain number of megabytes, an email attachment limit, or simply a preference for output files that stay under a predictable size regardless of how wide or narrow the rows are.
Turbo CSV Splitter's File Size method addresses this directly: instead of counting rows, it rolls over to a new part as soon as the current one reaches your target size in megabytes. Use it when the constraint is a size cap rather than a row count, an upload portal that rejects files over 100 MB, for example, or an email attachment limit.
Because rows vary in width, size-based parts hold different row counts but all stay near your chosen size, unlike row-based splitting, which produces consistent row counts but variable file sizes depending on how much text each row contains.
This method is the right choice whenever the actual limiting factor in your workflow is bytes rather than records, matching your split output directly to whatever size constraint you're working around.
The header is repeated at the top of every size-based part, keeping each one independently valid regardless of exactly how many rows happened to fit before the size threshold was reached.
Everything runs offline, entirely on your own Windows PC, so splitting a file by target size never requires uploading the original file anywhere to test whether it meets a size limit. Delimiter and encoding both default to Auto and are detected directly from the file itself, so you only need to touch them in the rare case detection gets something wrong, an unusual delimiter or a legacy encoding, for example. This makes the tool equally useful for data analysts working with irregular exports, developers automating a recurring pipeline step, e-commerce teams distributing catalog data by category, and anyone else who regularly runs into the practical limits of opening a large CSV file directly in a spreadsheet program.
- Install Turbo CSV Splitter on your Windows PC.
- Browse to or drag and drop your CSV file.
- Choose your output folder.
- Select the File Size split method.
- Set your target size in MB.
- Run Preview to confirm the setup.
- Click Start Split and monitor progress.
- Open the output folder to find your size-limited files.
- Adjust the parallel worker slider (1-128) if compressing many output parts.
- Check the status bar for the final row count and file count summary.
- Rolls over to a new file once a target MB size is reached
- Matches output directly to upload or attachment size limits
- Header repeated on every size-based part
- Works regardless of how wide or narrow individual rows are
- Ideal when the constraint is bytes rather than row count
- Live progress with speed and ETA
- Runs fully offline with no uploads required
- One-time purchase for Windows, with Gumroad license activation
- Compression options: uncompressed, per-part ZIP/gzip, or a single bundled archive
- Works with files on local drives, external drives, and network shares
How is this different from splitting by row count?
Row-count splitting produces files with a consistent number of rows but variable file sizes; File Size splitting produces files near a consistent target size but with variable row counts, since row width differs.
When should I use File Size instead of Number of Rows?
Use File Size when your actual constraint is a byte or megabyte limit, such as an upload portal or email attachment cap, rather than a row count limit.
Will every output file be exactly my target size?
Files roll over once they reach approximately your target size; since the split happens at row boundaries, the exact size may vary slightly around your target.
Does the header count toward the target file size?
The header is included in each file's size, though its contribution is typically small relative to a substantial target size in MB.
Does this work on both Windows 10 and Windows 11?
Yes, Turbo CSV Splitter is built and tested for both Windows 10 and Windows 11.
Is my data safe when using this tool?
Yes, all processing happens locally on your PC; no files are ever uploaded, so proprietary or sensitive data stays fully under your control.
Can I compress the split output files?
Yes, you can leave parts uncompressed, zip or gzip each part individually, or bundle everything into a single ZIP or gzip archive, sped up by a parallel worker slider.
Can I use this on files stored on an external or network drive?
Yes, CSV files on local drives, external drives, or mapped network shares all work the same as any local file.
Can I cancel a split job partway through if I need to?
Yes, cancelling saves a checkpoint file in the output folder, so you can resume the job later exactly where it left off instead of starting over.
Is there a trial version available before buying?
Check the product page on turbo-soft.com for current trial availability and details.
Ready to split your CSV file by target size, fully offline?