A rafter square, also called a speed square, is a versatile triangular carpenter's tool for quickly marking angles like 90° and 45°, finding roof pitches (common, hip, and valley) using its built-in scales for rise/run, and making precise cuts for rafters, as well as layout for doors, windows, and other carpentry projects. Key features include a base, a protractor edge for angles, a pivot point, and markings for common rafter dimensions and angles, allowing carpenters to efficiently mark cuts li