# How to Use a Speed Square

## Introduction

Speed squares aren't just for marking 90- and 45-degree angles when you're cutting 2x4s. You can use a speed square to find roof pitches, guide your circular saw and more—including marking any angle from 0 to 90 degrees.

• Circular saw
• Speed square

## What is a Speed Square?

Ever wonder why every contractor you see has a triangular square stuck in his tool belt? This cheap, handy little tool is called either a rafter square or a speed square, and it can offer you the biggest bang for the buck in your toolbox. This tool has dozens of uses; here are three of our favorites.

Step 1

## Find Roof Pitch

• Place the pivot point against the shingles.
• Then place a torpedo level on the fat base of the speed square.
• Adjust the square until the level is level.
• Read the pitch on the side of the speed square.
• Note: The pitch tells you the amount of vertical rise (in inches) for every 12 inches of run.

Step 2

## Mark Angles

• Swing the speed square until you read the desired angle on the board’s edge.
• Mark the angle on the board.
• Note: The example shows a 33-1/2 degree angle.

Step 3

## Guide Saw Cuts

• Cut 45- and 90-degree angles by using the speed square as a guide.
• Pro tip: This method works better (and safer) when right-handed users have a circular saw with the motor to the right of the blade (like in the photo).