An exercise ball, also called a swiss ball or stability ball, is a large inflatable ball people use for core exercises, stretching, balance work and as a seat. The size you need depends mostly on your height, because the ball has to put your hips and knees at the right angle when you sit on it. Below is a size chart, a quick sitting test, what anti-burst means, how firm to pump it up, and every exercise ball we stock in NZ, grouped by size. The whole range is in bosu and swiss balls.
Exercise ball size by height
This is the size chart on our swiss ball product pages. If your height is close to the edge of a band, the sitting test below decides it.
- 55cm ball: 140cm to 165cm tall
- 65cm ball: 165cm to 185cm
- 75cm ball: 185cm to 195cm
- 85cm ball: 195cm and over
The 45cm ball is child sized, so it’s the one to get for kids.
The sitting test
Pump the ball up to its full size and sit on the top of it with your feet flat on the floor, about hip width apart. Your hips and knees should both be at about 90 degrees, with your thighs close to level or your hips a little higher than your knees. If your knees end up higher than your hips, the ball is too small or too soft. If your feet barely reach the floor, it’s too big or pumped up too hard. People with long legs for their height often go up a size.
Anti-burst balls and load ratings
An anti-burst ball is made to let air out slowly if it’s punctured, instead of popping. Most of our swiss balls are sold as anti-burst, including the LivePro 65cm Swiss Ball with Pump, the 55cm, 65cm and 75cm Swiss Ball Anti Burst with Pump models, the 85cm Swiss Ball with Pump, Anti-Burst and the two peanut balls.
Each ball also has a load rating. The LivePro 65cm, the 65cm White, the 55cm Purple and the 75cm Black are rated to 300kg. The 85cm Swiss Ball is tested to exceed 800kg. The Avec Professional Swissball range is the commercial one, rated for loads up to 800kg. The 55cm Swiss Ball Pink takes up to 200kg, and the Donut Fitness SwissBall Blue 136kg. If you plan to hold dumbbells while you’re on the ball, count that load too.
Pumps and plugs
Most balls come with something to pump them up. The LivePro 65cm, the 65cm White, the 45cm Swiss Ball with Pump, Small and the 85cm come with a foot pump. The 55cm Purple, the 75cm Black and both peanut balls come with a hand pump, and the SKLZ Fitness Swiss Ball 65cm includes a pump too. Most also include a spare plug.
If you lose a plug or want a spare pump, the Replacement Plug for Swiss Ball comes with a plug remover, and the Ball/Cushion Hand Pump has a pin nozzle for ball valves.
How firm to pump it up
Pump the ball to its listed size. To check, stand it next to a wall and measure from the floor to the top: a 65cm ball should be about 65cm high. A new ball is often stiff, so many people pump it most of the way, leave it a day, then top it up.
Firmness changes how the ball behaves. A firmer ball is bouncier and rolls more easily, so exercises feel harder to control. A softer ball sits lower, spreads out under you and feels steadier, which suits people new to ball work. Balls lose a little air over time, so check the height every few weeks.
Other shapes
- Peanut balls are two balls joined in the middle, so they only roll in one direction. We have a 90cm x 45cm in blue and a 100cm x 50cm in red.
- Half balls are flat on one side and domed on the other. The Half Round Balance Ball LivePro Grey can be used flat side up or round side up for push-ups, sit-ups and balance work.
- The Donut Fitness SwissBall is flat sided, about 25cm x 45cm, so it doesn’t roll away when you sit or kneel on it.
- The Mini Inflatable Therapy Ball with Pump is a small peanut shape, 27cm long by 13cm wide.
Using an exercise ball at home
A few common exercises to start with:
- Ball crunch: lie with your lower back on the ball and feet flat, then curl up.
- Plank with your forearms on the ball.
- Hamstring curl: lie on your back with your heels on the ball, lift your hips and roll the ball in and out.
- Wall squat with the ball between your back and the wall.
- Stretching: lie back over the ball, or kneel and roll it forward to stretch through your shoulders.
Use the ball on a mat or carpet in a clear space, away from anything sharp or hot. Some people also sit on a ball at a desk for part of the day. The SwissBall Chair holds the ball in a frame with four wheels, and the Swiss Ball Base keeps a single ball in place or stores it when you’re done. For more balance and core gear, see speed, agility, balance and core.
Exercise balls by size
Exercise ball questions
What size exercise ball do I need?
Go by your height using the chart above, then sit on it. Hips and knees at about 90 degrees with your feet flat means the size is right.
Can two people of different heights share a ball?
Often, yes, if they’re within a band of each other. Pumping the ball a little softer lowers it for the shorter person.
What does anti-burst mean?
The ball is made to go down slowly if it’s punctured, instead of popping.
See the full range in bosu and swiss balls, or read our other buying guides. We ship NZ-wide.