Combine 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. Before you run it on a workbook other people depend on, try it on a copy or a few rows first. Undo only reaches back through the current session, so a quick trial run is the cheapest way to see exactly what will change before the file is saved and shared. For “combine csv files in excel”, the reliable version is a short checking loop, not just the first command that appears to work. Run it on a deliberately small range first, watch how the affected cells change, and only then apply the same setup to the full sheet. 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. That is what makes a text operation that turns messy entries into clean, usable data useful in real work: repeatable, auditable, and not dependent on memory or luck.

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. If this is something you do often, add the command to the Quick Access Toolbar (right-click it on the ribbon and choose Add to Quick Access Toolbar) or learn its shortcut, so next time it is one click instead of a hunt through the menus.

In Google Sheets

This is a command rather than a formula, so there is no syntax to carry over. Google Sheets arranges its commands in menus across the top instead of a ribbon, names some of them differently and does not have every Excel command — look for the equivalent in the Sheets menus or its help before assuming the steps match. 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 and the detail above shows why it holds — so the next time a colleague asks, you can answer without reaching for search. The short version of “combine csv files in excel”: the answer is at the top of this page, and the sections above explain why each step matters, so a variation of the problem does not stump you. Try it once on a copy of a real file and the steps stick far better than re-reading them.

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