Withdata DataFileConverter merges Excel files into one fixedwidth file locally — any number of files, mapped column by column, with the output options of your choice. 100% local, secure, and cross-platform.

Why Choose Withdata DataFileConverter as a Excel Merger?

🔒 100% Local & Secure

All merging runs on your own computer. Nothing is uploaded to any cloud server.

⚡ Fast Streaming Merge

Millions of rows within a minute. Large files are streamed with low memory usage.

📁 Any Number of Files

Add two files or a whole folder, then combine everything into a single Fixed-Width Text file.

🔄 Column Mapping

Files with a different column order or extra columns can be mapped to the output columns before merging.

🖥 Windows, macOS, Linux

Native builds for Windows, macOS and Linux, with a step-by-step GUI wizard and a command line interface.

⏱ CLI & Scheduled Tasks

Save a merge session and run it automatically from Windows Task Scheduler or crontab.

Full Feature Comparison

Feature	Supported details
Input	Any number of Excel files, added one by one or as a folder
Output format	Fixed-width text with auto-detected or custom column widths
Merge mode	All input rows into one output file
Running mode	GUI wizard · command line · scheduled tasks
Column handling	Source columns are mapped to the output columns
Output options	Column widths (auto-detected or manual), header row, encoding
Platform	Windows, macOS, Linux (native, 64-bit)

Excel to Fixed-Width Text — What Changes

Sheet rows become fixed-width lines. Formatted numbers and dates are resolved to text first, because a fixed-width column has no type of its own.

All Excel Merge Options You Need

Merge several Excel files into one Fixed-Width Text file — step by step in the GUI wizard
Merge a whole folder of Excel files in one run
Map the columns of each input file to the output columns
Run the merge from the command line, and schedule it as a scheduled task
All Excel tools and all Fixed-Width Text tools

Same source format, other targets

This page merges Excel into another format. If you need a different output, these pages each do that one job:

All merge tools, by format

Merging into Fixed-Width Text — Notes

There is no delimiter and no quoting — every column has a fixed width.
Merged output widths are measured from the data (widest value plus 15% slack, at least 2 and at most 15 extra characters) and can be edited.
For N columns, N-1 widths are used — the last column takes the rest of the line.
When reading fixed-width files: N columns need N-1 widths, no delimiter is used, and the header row is optional.

How to Merge Excel Files (4 Steps)

Open Withdata DataFileConverter and choose Merge (combine multiple files into one).
Add the Excel files you want to merge — two files, a list, or a whole folder.
Check the preview and map the source columns to the output columns; then set the output options (Column widths (auto-detected or manual), header row, encoding).
Click Convert — the single Fixed-Width Text file is written in seconds. Save the session if you want to run it again from the command line.