The suit or sportcoat size in the US is described as a number, referring to your chest measurement, and a letter, describing the jacket length. To find the corresponding pant size, see the pant conversion below. Don't know your size? Check out our Measuring Guide or come into a Men's Wearhouse Store.

* To get accurate measurements, you will need a soft measuring tape and a friend or partner to help out. Of course, you can always stop in to any Men's Wearhouse and we'll be happy to take your measurements

Step 1: Chest Measurement Wrap the tape measure around your torso. Go underneath your arms, across your shoulder blades, and over the largest part of your chest. The chest measurement is usually the size of the coat. For a more relaxed fit, add 1 inch to the total measurement.

Step 2: Over Arm Measurement However, if your over arm measurement is more than 7 inches larger than your chest measurement, the over arm measurement trumps the chest measurement. In this case, your suit size needs to match your over arm measurement.

Your over arm measurement is important, particularly if it is larger than your chest measurement. If this is the case, you will need to fit your chest and upper arm rather than rely on the chest measurement alone. For example, if your chest measurement is 40 inches and the over arm measurement is 49 inches (remember, you subtract 7 from the over arm measurement), you will likely want to start with a size 42 to accommodate your larger upper arms and shoulder width.