Merge CSV files
Append two pasted CSV tables or 2–20 files with matching headers into one table.
- 1Add input
- 2Adjust settings
- 3Get your result
Tool input and files are processed in this browser without being uploaded.
Before you start
Combine CSV records vertically, keeping one header row. Paste two tables or choose multiple files, verify their headers and order, then download the complete result.
How to use this tool
- Paste two headered tables or choose 2–20 UTF-8 CSV, TSV or TXT files in the order you want.
- Choose the input delimiter and confirm every source has the same column names. Reorder selected files with the arrows if needed; reordered columns are flagged before merging.
- Merge, check the row count from each source and the output preview, then copy or download the complete CSV.
Supported inputs and limits
Every source needs the same unique, nonempty column names and equal row widths. Columns in a different order are aligned by name to the first source. This appends rows; it does not join records by an ID or add different columns.
Paste two tables of up to 1 MiB each, or choose 2–20 UTF-8 files up to 10 MiB each and 30 MiB combined. The result must also fit 200,000 cells, 1,000 columns and 20 MiB; meeting the input limits does not guarantee an export.
Files and input are processed in this browser. No account needed.
Table headers, preview cells and displayed column or filter values show at most 240 Unicode characters, followed by an ellipsis when shortened. Metadata JSON previews show the first 20,000 Unicode characters when limited; use the complete metadata JSON copy button for the full document. CSV copy and download remain complete.
Worked example
Example input
name,age Mori,3
Example options
{}Example output
name,age Mori,3 Amy,2
When something does not work
Choose the correct delimiter, check that every source has the same unique column names and row widths, and correct a source with missing or extra columns before merging.
Frequently asked questions
How can I check the result from Merge CSV files?
Check the source order, each source row count, identical headers and the first output rows. The result has one header row and all data rows in source order. Cell text, including formulas and leading zeros, is preserved; output uses comma-delimited CSV with normalized quoting and record endings.
What should I check before using the result?
This appends rows with matching column names, aligning their order. It does not join by a key, deduplicate rows, rename columns or combine XLSX workbooks.
Is my input sent to a server?
No. Tool input is processed in your browser, not sent to a server. Temporary workspaces stay in the same tab and are cleared by a refresh or tab closure. Save the results you need.