How do I get the right size for a motorized roller shade?

Several listings here are custom-size or offer multiple width-and-height options, so measure your window opening carefully and decide between an inside mount (fits within the frame) and an outside mount (covers the frame for better blackout). For wide windows, look specifically for models rated for larger widths, as motor torque and roll diameter limit how big a single shade can go before sag or slow operation becomes an issue.