How to use Merge CSV Files
Combine exports by matching column headers.
- Choose multiple CSVs. Headers are matched after trimming whitespace, and columns missing in a file are left blank. Preview and export the combined table.
- Process the selected files, then inspect the preview, dimensions or warnings.
- Download a new copy and check it before replacing or sharing the original.
How processing works
Output columns are the union of header names across files. Each row is aligned by matching header text, with empty cells where that source file has no matching column.
A quick example
Merge January and February exports even when their columns are in a different order.
Assumptions, edge cases & limits
- Header spelling and letter case must match to join the same column.
- Rows are appended, not joined by a database key; duplicates remain unless removed separately.
- Header matching is case-sensitive after trimming. Review the combined columns before saving.
Questions about Merge CSV Files
Can I merge CSV files with different column orders?
Yes. Columns are matched by header name rather than position. New headers are added to the output and missing fields are left blank.
Does merging combine matching customer records?
No. This is an append operation, not a relational join or an update by customer ID. Use duplicate review afterward if repeated records should be removed.
Are my files or inputs uploaded?
Calculation and file processing run in your browser without a processing upload. Downloads go to your device. Choosing a next-step transfer creates a temporary local copy for that workflow. Region preferences are stored separately from tool inputs. See our privacy details.
Can I use this tool for free?
Yes. No signup, subscription or payment is required to use the tool or download its output. File tools have device and size limits; a smaller batch may work better on a phone.
A result or explanation needs correcting? Tell us the tool name and an example.