Split a large CSV into smaller chunks, delivered as a ZIP.
All processing happens in your browser — files never upload anywhere.
Split CSV runs entirely in your browser using SheetJS (community edition, MIT-licensed) and JSZip. Your workbook never leaves your device, so it's safe for confidential financial data, HR spreadsheets, and other sensitive files.
SheetJS (the community MIT-licensed Excel WASM library) with JSZip
Every step runs on your device — nothing is uploaded.
Open Split CSV on Toolspace.
Drop your .xlsx, .xls, .xlsm, or .csv file.
Pick the mode / target format from the controls shown.
Click the action button to run SheetJS and download the result.
Split CSV is powered by SheetJS (community edition), the same library used by Microsoft's own Office online tooling. It handles workbooks up to ~1 million rows in browser memory. Above that, use the Split Excel tool first to chunk your workbook.
No. Split CSV runs entirely in your browser — SheetJS parses the .xlsx binary format locally, transforms it, and returns the output. Nothing hits our servers. Financial data, HR spreadsheets, and other confidential workbooks are safe.
Formulas and cell data types are preserved. Cell styling (colors, borders) is preserved for XLSX-to-XLSX operations. Charts and macros are trickier — they're preserved when re-writing XLSX but lost when converting to lossless-only formats like CSV.
Split CSV accepts .xlsx, .xls (Excel 97-2003), .xlsm (macro-enabled), and .csv inputs. Output depends on the specific tool — see the accepted-formats hint in the drop zone.
Excel's own limit is 1,048,576 rows per sheet. Split CSV respects that. In practice, browser memory becomes the limit around 500,000-800,000 rows depending on cell density.
Yes — export your Google Sheet as .xlsx (File → Download → Microsoft Excel), then drop it into Split CSV.
All free, all browser-based, all zero-signup.