File size, not row count, is often the real constraint that matters: a storage system with a per-file cap, a transfer process that struggles with very large single files, or simply a practical need to keep individual files within a size that's comfortable to handle and move around.
Turbo CSV Splitter's File Size method divides a large CSV file directly by size, rolling over to a new part as soon as the current one reaches your target size in megabytes, rather than dividing based on any particular row count.
This approach directly targets whatever byte-based limit you're working within, whatever number that limit happens to be, without needing to first calculate or guess at a corresponding row count that would produce files near that size.
Because CSV rows can vary significantly in width depending on how much text each field holds, size-based division produces more predictable file sizes than a row-count approach would when the actual constraint is bytes rather than records.
Every size-based part carries the header at the top, keeping each output file complete and independently valid regardless of how the actual row count happened to land within your target size.
Everything runs offline, entirely on your own Windows PC, so dividing a large file by size never requires uploading it to test against an external size limit first. 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 large 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-divided 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.
- Divides a large file based directly on target file size
- Matches output to byte-based limits without row-count guessing
- Header carried on every size-divided part
- More predictable sizing than row-count division for size constraints
- Works on files of any total size via streaming
- 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
Why does file size matter more than row count in some cases?
Storage systems, transfer processes, and upload portals often cap based on bytes rather than record count, so a size-based split matches those constraints more directly.
Does splitting by size work well even with rows of very different lengths?
Yes, since the method rolls over based on actual accumulated size rather than a fixed row count, it adapts naturally to varying row widths.
Can I combine size-based splitting with other data cleanup?
Yes, column tools, filters, sorting, and deduplication can all be applied as part of the same workflow before the size-based division runs.
Is the header included in the size calculation for each part?
The header contributes a small amount to each file's total size, though its impact is typically minor relative to a substantial target size.
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 divide your large CSV file by size, fully offline?