Merge CSV Files in Excel

What this does

A .csv is plain text, not an Excel file — Excel merely knows how to display it. Double-clicking lets Excel guess the delimiter and data types, which is where mangled umlauts, stripped leading zeros, and dates like 1/2 turning into February 1st come from. Importing through Data ▸ From Text/CSV (Power Query) shows a preview where you control the delimiter, encoding, and per-column types before anything is loaded. Most people learn this as a sequence of clicks and forget it by next week; learning it as a pattern instead is what lets you apply it to the next, slightly different version of the problem without starting from scratch. That is the difference this page is trying to make. The difference between a quick fix and a sheet you can trust is the extra minute you spend validating “merge csv files in excel”. Start on a copy or a tiny sample, keep the affected cells visible, and compare the result with the tool above before you touch the real workbook. When this is a ribbon command, the selection matters more than the button: confirm the range, apply the command, then spot-check the output before saving. The point is a data step that keeps your analysis trustworthy, but the practical win is that someone else can open the file and understand what happened without asking you.

A worked example

A bank export orders.csv uses semicolons and contains the customer number 007. Double-clicked, Excel shows 7 in one column on some systems and everything-in-column-A on others. Imported via From Text/CSV with delimiter Semicolon and the customer column set to Text, it loads as 007 in its own column — then File ▸ Save As .xlsx makes it a real workbook. Almost every system exports CSV, and almost every recipient wants a clean spreadsheet. Controlling the import (or converting directly) prevents the classic silent data corruption: lost zeros, wrong dates, broken characters. One habit worth forming early: name the cells that hold your inputs, so the formula reads in plain language instead of a string of cell addresses. A reviewer — or you in three months — can then follow the logic without decoding what B7 and D2 were supposed to mean, which is most of what makes a sheet maintainable.

In Google Sheets

Everything above works in Google Sheets too. Excel and Sheets share the formula syntax used here; only the surrounding menus are arranged differently. That portability is deliberate — learn it once and it follows you between the two tools and across Windows and Mac. The aim was to get you unstuck fast and leave you a little more capable than a copy-paste would. The answer is at the top, the tool proves it, and the detail above shows why it holds — so the next time a colleague asks, you can answer without reaching for search. If you take one thing from this page on “merge csv files in excel”, make it the habit rather than the keystrokes: set the problem up with labelled inputs, reference those cells, and let Excel do the recomputing. Bookmark the page for the syntax, but do the example once in a blank sheet and check it against the tool above — five minutes of hands-on practice fixes the method in memory far better than re-reading, and it surfaces the small snags while they are still harmless. After that the technique is genuinely yours: faster than searching for it again, and reliable enough to drop into work that other people depend on.

Common mistakes

• Double-clicking the CSV and letting Excel guess the delimiter and types.
• Losing leading zeros because numeric-looking IDs were auto-typed as numbers.
• Broken ä/ö/ü because the file is UTF-8 but was read as ANSI — set File Origin to 65001: Unicode (UTF-8).
• Saving the imported data back as .csv and wondering where the formatting went — save as .xlsx.

Frequently asked questions