Key Takeaways
- The free CSV splitter separates one file by row count, by number of parts or by a column value.
- The same tool merges several CSVs that share a header into one file.
- Everything runs in your browser, so nothing is uploaded.
- For splitting and reassembling data inside a spreadsheet, Flookup Data Wrangler adds matching and cleaning.
Introduction
A file is too large for the system that needs it. Or you have a folder of monthly exports that should be one file.
Both tasks are routine, and both should take seconds.
The free CSV splitter and merger cuts one file into smaller ones or joins several back together, in your browser. Open the CSV splitter and merger.
Splitting and Merging in One Tool
Split and merge are two faces of the same job, so the tool handles both. In split mode one input becomes many outputs. In merge mode many inputs become one output. No upload, no size limit imposed by a server.
Three Ways to Split
Choose the split that matches your reason for splitting:
- By rows per file: set a maximum row count and every file comes out at or below it, handy for import limits.
- By number of parts: say how many files you want and the rows are divided evenly between them.
- By column value: group rows by a column so each country, region or category gets its own file.
Each output keeps the header row, so every file stands on its own.
Merging Files with a Shared Header
Merging is the reverse. Give the tool several CSVs that share the same columns and it writes one file with the header once and every file's rows in order. This is the usual fix for monthly or per-region exports that should be a single table.
The one requirement is a matching header. If columns differ, standardise them first with the free CSV Editor so the rows line up under the right headings.
Privacy First
Files are read and written in a background worker in your browser.
Nothing is uploaded, stored or logged, so you can split customer exports and internal reports without a second thought.
How to Use It
- Choose split or merge mode.
- Open a file or paste the content, or load several files when merging.
- For a split, pick rows per file, number of parts or a column value.
- Press Split or Merge, then download the resulting files.
Common Pitfalls
- Headers that do not match on a merge: one differing column name shifts the data. Align the headers before merging.
- A column value with many distinct entries: splitting by column can produce hundreds of tiny files. Use rows or parts when you just need size control.
- Quoted line breaks: a field containing a line break is kept intact, so split counts follow records rather than raw lines.
- Reaching for a spreadsheet: very large files defeat spreadsheet import limits. Split first, then open the parts.
When to Split or Merge
- Cutting a large export into parts that each fit an import limit.
- Sending one file per region or owner by splitting on a column.
- Combining monthly exports into a single table for analysis.
- Reassembling parts after a downstream tool has processed them.
- Producing evenly sized files for a batch upload.
Beyond One-Off Splits
The splitter works on one file at a time and does not match records across files. When you need to merge duplicate rows, not just stack files, the Flookup Data Wrangler add-on brings deduplication and fuzzy matching into Google Sheets. The CSV joiner handles exact-key joins between two files.
One Big File Should Not Be a Blocker
Files arrive too large and too many, and reshaping them should not need a script. The CSV splitter cuts a file by rows, parts or column value, and the merger stacks files back into one, all in your browser.
Nothing leaves your device, so you can reshape sensitive exports freely.
For matching and merging records inside a spreadsheet, Flookup Data Wrangler brings the same workflows into Google Sheets.