Splitting a CSV by raw text lines can break records containing quoted line breaks. A CSV-aware tool reads records first, then writes valid CSV files with the header repeated.

Choose a row count

Open Split CSV and choose the number of data rows per part. The header does not count toward that number. For example, 2,500 data rows split into parts of 1,000 produce three files with 1,000, 1,000, and 500 data rows.

Inspect the ZIP output

The download contains numbered CSV files. Check the first and last records of adjacent parts and confirm the column names. FileToast parses quoted fields and writes UTF-8 CSV output; it does not preserve the exact source delimiter or original whitespace.

Combine matching files again

Merge CSV files requires matching headers in the same order and keeps a single header. Use Select CSV columns first if you need to reorder columns.