Stand with your feet hip-width distance apart, holding one dumbbell vertically close to your chest, beneath your chin, with both hands.
Slowly bend your knees as if you were going to sit in a chair, keeping all the weight in your heels. Don't let your knees move beyond your toes, and don't let the knees roll out or in. Squat down as low as you can, keeping your head and chest lifted, your spine long, and your shoulders relaxed.
Press through your heels and slowly straighten your legs to stand up, completing one rep.