🧩 I Built a Simple Tool to Merge Excel Files — the Lazy Way

#webdev #javascript #html #ai

Introduction

Merging multiple Excel files into one — it’s probably more common in the workplace than we’d like to admit.

For example:
・Sales reports from different departments
・Daily CSV log files
・Survey results filled out by different team members

You’ve likely heard (or said) this before:

　“Can you just combine them all into one file?”

But opening each file and copy-pasting manually is a pain.
Writing VBA macros is annoying.
Spinning up Python with pandas just for this? Also overkill.

🎉 So I Built a "Lazy Merge" Tool for Excel

I created a lightweight web tool where you can simply drag and drop multiple Excel files into your browser, and the tool merges them all and copies the result to your clipboard.

✅ No installation required — runs entirely in your browser
✅ Supports .xlsx, .xls, .xltm, and .csv
✅ Automatically extracts the first sheet of each file
✅ Combines the data into one and copies it instantly
✅ Paste into Excel — merge complete!

Perfect for quick tasks, admin work, or when you just want to get it done.

💡 How to Use It

It’s dead simple:

Open the site (either hosted or saved locally)
Drag & drop multiple Excel files at once (.csv, .xltm, etc.)
Click the 📋 Copy All button
Open a new Excel file and paste the result

That’s it! 🎉
The merged content is handled as tab-separated values (TSV), so the result is cleanly formatted when pasted into Excel.

🔧 What’s Under the Hood?

This tool is built with:

・HTML + JavaScript (frontend only)
・SheetJS(xlsx) for parsing Excel/CSV files
・FileReader API for reading files in-browser
・Clipboard API for copying to clipboard

Everything runs locally in your browser.
✅ No server
✅ No uploads
✅ Your data stays on your machine.

🧪 After Using It Myself...

Originally, I built this tool thinking,

　“I just want a quick little utility for myself.”

But it turned out to be so useful, I’ve kept it around and even shared it with coworkers.

・No more VBA or macro maintenance
・No code — anyone can use it
・Everything self-contained in a single HTML file

If you’re looking for a no-frills, anyone-can-use tool — this is it.

✅ Summary

・I built a simple browser-based tool to merge Excel/CSV files
・Just drag & drop → click → paste. Done.
・Works offline, no installation needed
・Handles .xltm and other formats thanks to SheetJS

Whether you're in admin work, data processing, education, or just looking to save time —
I hope this helps!