Data Analysts
Use Split CSV into Chunks to prepare split csv into chunks results for repeatable reporting, exports, and data quality checks.
PRIVATE BY DEFAULT. INSTANT BY DESIGN.
Large CSV Splitter & ZIP Download
Split by row count, equal file count or UTF-8 byte size, with headers repeated and a local ZIP export.
0 characters
Your CSV files stay in this browser.
Before & after: Split CSV into Chunks
BEFORE · INPUT
id,name 1,Ada 2,Alex 3,Sam
AFTER · OUTPUT
id,name 1,Ada 2,Alex 3,Sam
How to use Split CSV into Chunks
01
Add CSV data
Paste CSV or drop local files. Joining requires a primary table and lookup table.
02
Choose options
Select match columns and join rules, chunk limits or source encoding and line endings.
03
Process locally
Run the task in a cancellable browser worker. Review the preview and result summary.
04
Download your result
Download joined or repaired UTF-8 CSV, or a ZIP of chunks with repeated headers.
Real-world workflows
Software Engineers
Use Split CSV into Chunks to transform source content for integration fixtures, debugging, or code review directly in the browser.
E-Commerce Managers
Use Split CSV into Chunks to adapt product catalog exports and order spreadsheets for downstream inventory workflows.
Technical edge cases & frequently asked questions
Do my CSV files leave this browser?
No. Parsing, joins, repair and ZIP generation run in local browser workers. No source is uploaded.
How are duplicate and blank join keys handled?
Duplicate right keys expand to all matching rows. Blank keys do not match. Full joins copy unmatched right keys into the left match column. Matching trims whitespace and ignores case by default.
What are the practical limits?
Combined decoded sources have a 64 MiB cap; joins cap results at 1,000,000 rows and splitting caps output at 1,000 files. Device capacity varies; no under-50-ms guarantee. Quoted multiline fields are preserved and every chunk repeats its header.
Can all broken encodings be repaired?
No. Files use strict UTF-8 detection with Windows-1252 fallback; ISO-8859-1 is ambiguous and browser decoding maps it to Windows-1252. Reversible mojibake can be repaired, but lost replacement characters cannot be recovered. Review punctuation before export.
| Encoding | UTF-8 (text) |
|---|---|
| Processing | Local JavaScript / browser Canvas |
| Max recommended file size | 50 MB+ may work; browser memory and tool complexity determine capacity. Start smaller. |
| Server retention | 0 bytes — no server uploads |