Unreal Engine 4 (UE4) is free to download and use for game development, but finding a single "offline installer" (like an .exe or .msi that contains the entire engine) is not the standard procedure for individual users.
: Install UE4 on a computer with internet, then copy the engine folder (typically found in C:\Program Files\Epic Games\UE_4.X ) to an external drive. You can run the editor directly from the folder on another computer via Engine\Binaries\Win64\UE4Editor.exe without the launcher. unreal engine 4 free download offline installer
Epic has moved to Unreal Engine 5 as their primary supported version. UE4 is now a legacy product, and Epic no longer provides official standalone offline installers for it. Unreal Engine 4 (UE4) is free to download
There is no official, public "offline installer" for standard individual users. To get Unreal Engine 4 (UE4) for free, you must typically use the Epic Games Launcher while connected to the internet. Unreal Engine is distributed by Epic Games