Measuring Your Shoulder Width Accurately
First, let’s talk about why shoulder width matters. When you lie down, your head and neck need to stay in a neutral position—imagine a straight line from your ear down through your shoulder and hip. If your pillow is too high, it forces your neck to bend upward, straining the muscles. If it’s too low, your head drops down, pinching nerves and cutting off circulation. The gap between your side and your head is filled by that pillow, and that gap is largely determined by how broad your shoulders are. A side sleeper with wide shoulders needs a tall loft—often four to six inches—while a person with narrow shoulders might only need two to four inches. Stomach sleepers generally need the thinnest pillows, sometimes just one to two inches, to avoid cranking their neck backward.
So how do you measure your shoulder width at home? You’ll need a flexible measuring tape and a friend, or a sturdy wall and a little patience. Stand up straight with your shoulders relaxed—don’t puff them up or slouch forward. Have your friend measure from the bony bump on the outside of one shoulder, called the acromion process, straight across your back to the same point on the other shoulder. This is your biacromial width. If you’re doing it solo, stand with your back to a wall, press your shoulders against it gently, and mark where each shoulder hits. Then measure between the marks. For most American adults, that width falls between sixteen and twenty-two inches. A measurement under eighteen inches is considered narrow, eighteen to twenty is average, and over twenty is broad.
Now, here’s where pillow loft comes into play. The goal is to close the gap between your shoulder and your head when you’re lying on your side. A simple rule of thumb: take your shoulder width in inches and divide by two. That number is roughly the loft height you need for side sleeping. For example, if your shoulders measure eighteen inches across, look for a pillow with a nine-inch girth? No, that’s too literal. Actually, the loft is about half of the shoulder width once you account for compression. A better method: lie on your side with a pillow and have someone check if your spine is straight. If your chin is tucked down, the pillow is too high. If your head tilts up toward the ceiling, it’s too low. Trust the feel.
Back sleepers need a different approach. Here, a pillow should support the natural curve of your neck without pushing your head too far forward. Measure the distance from the back of your head to the wall when you lie flat on the floor or a firm mattress and press your chin slightly downward. That distance, usually two to four inches, is your optimal loft. Stomach sleepers, meanwhile, often skip pillows altogether or use a very thin one, under three inches, to avoid twisting the cervical spine.
Once you have your shoulder width and preferred sleep position, you can shop with confidence. Look for pillows marketed as “side sleeper,” “back sleeper,” or “adjustable loft.” Adjustable pillows with removable fill are especially forgiving because they let you dial in the height after you measure. Memory foam and latex pillows tend to hold their loft better than down or polyester, which compress more over time. And don’t forget your mattress firmness—a softer mattress lets your shoulder sink deeper, so you might need a slightly lower loft to compensate.
A final word from SleepGoals: Your pillow is not a one-size-fits-all purchase. It’s a custom fit for your unique frame. Sleep is the foundation of your health, and a properly aligned spine means fewer aches, better breathing, and more restorative rest. So grab a tape measure, find your shoulder width, and give yourself the gift of a pillow that actually works for you. Your neck—and your next morning—will thank you.
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