CSV Merger
Append two CSV tables vertically, matching reordered headers or combining different schemas with a union of columns.
Start with your input
Edit the example or replace it with your own text.
Choose your options
These settings are optional. Keep the defaults to get started.
How to use CSV Merger
- Load the example or enter your own values.
- Choose the relevant options and run the tool.
- Review the result, then copy it or download a local file.
When this tool is useful
Combine small exports from successive days or separate sources into one table with a single header row. Unlike joining by a key, merging appends records vertically and keeps every source row. The second table may use a different column order because cells are aligned by header name. Union mode also keeps columns that appear in only one of the tables.
Reading the result and limitations
Headers must be unique and nonblank. Strict mode requires the same set of column names; union mode keeps first-table columns first and appends new second-table columns. Missing cells are empty strings, which cannot distinguish an absent column from an explicitly empty value. Duplicate records are intentionally preserved. Inputs use comma-separated CSV with standard quoting, and output is limited to one hundred thousand cells for a responsive local conversion.
Example input
id,name 1,Ada 2,Grace
What are the main limits of CSV Merger?
Headers must be unique and nonblank. Strict mode requires the same set of column names; union mode keeps first-table columns first and appends new second-table columns. Missing cells are empty strings, which cannot distinguish an absent column from an explicitly empty value. Duplicate records are intentionally preserved. Inputs use comma-separated CSV with standard quoting, and output is limited to one hundred thousand cells for a responsive local conversion.
Is input uploaded?
Processing takes place in your browser. This tool does not send your input or selected files to a conversion API.