Originally Posted by 11515

Hey Michelle,

Personally, my ball sits a little lower then my normal chair; but ergonomically speaking its ok. It was awkward at first but I mentally adjusted. But then again I'm short and according to the chart below I should be using a smaller ball. I'm 5'3" and my ball is a 65cm one. You should purchase the ball according to the size recommended for your height. How tall are you?

Below is a chart I found that may help you decide the right size.

What Size is Right for Me?
The size of exercise balls varies. Physical therapists suggest using an exercise ball that fits each person's height and leg length, where the hips and knees are at or slightly greater than a 90 degree angle (thighs parallel to ground or point down slightly) with feet flat on the floor. It is best to work with a physical therapist or other spine specialist for a proper fit before using or purchasing an exercise ball.

Your Height
Ball Size

5' 3" and under
53 cm

5' 4" to 5' 10"
65 cm

5' 11" to 6' 4"
75 cm

6' 5" and over
85 cm