Question 1

What does the CSV File Splitter do?

Accepted Answer

It splits one large CSV into many smaller CSVs. You can split by row count (e.g. 1000 rows per file), by target file size (e.g. 1MB per file), by column value (each unique value becomes its own file), or by number of output files (split into N roughly equal parts).

Question 2

How is the header handled?

Accepted Answer

By default, the first row (header) is preserved at the top of every split file. You can turn this off if your CSV has no header row.

Question 3

How do I name the output files?

Accepted Answer

Use the filename template with placeholders: {base} (original filename without extension), {index} (zero-padded split number), {total} (total split count), {group} (column value when grouping), and {date} (current date). Example: '{base}_part{index}_of_{total}.csv' → 'sales_part01_of_05.csv'.

Question 4

Can I download all splits as one ZIP?

Accepted Answer

Yes. Click 'Download as ZIP' to get a single .zip containing every split. Or download individual files one at a time.

Question 5

What extra features does this tool have?

Accepted Answer

10 extras: (1) Drag-drop input. (2) Preview first N rows of each split. (3) Live stats (total rows, estimated split count, per-split row counts). (4) Custom delimiter (comma, tab, semicolon, pipe, or custom char). (5) Encoding detection (BOM sniffing). (6) Progress bar during split. (7) Split by number of output files (divide into N equal parts). (8) Column selection (keep or drop columns before splitting). (9) Dedup rows inside each split. (10) History (localStorage — last 10 split configs).

Question 6

Is my CSV uploaded anywhere?

Accepted Answer

No. All parsing, splitting, and ZIP packaging happen in your browser using pure JavaScript. Your data never leaves your device.

Question 7

What's the maximum CSV size?

Accepted Answer

There's no hard limit, but very large files (> 100MB) may slow the browser. We use efficient array operations and show a progress bar.

CSV File Splitter

How to use