How to Choose the Right Exercise Ball for You

What is an Exercise Ball?

An exercise ball or a yoga ball is a great fitness equipment that has everything you dream of for a killer workout or as a comfy alternative seating at home, in the office or gym. It is versatile, but not one-size-fits-all. Therefore, effectively using the exercise ball requires careful selection of just the correct size for you.

What is the Exercise Ball SIZE?

The size of an exercise ball refers to its diameter or height when inflated. The sizes of the Trideer exercise ball available are extra small (45cm/18") small (55cm/22"), medium (65cm/26"), and large (75cm/30"), extra large (85cm/33"). But of course, the size availability of different brands differs.

How to Select the RIGHT SIZE?

Choosing the exercise ball size based on your particular height is the standard way to go. This is to ensure perfect ergonomics while using it. Please check out the size chart below for your reference:


Two ways: measure the DIAMETER or CIRCUMFERENCE.

1. Measuring the Diameter: Pen-Mark-on-the-Wall

1) Make a mark on the wall at the desired height or diameter of your exercise ball using a pen or pencil.

2) Place a yardstick or long book on the top of the exercise ball parallel to the floor and against the mark to see if the yoga ball reaches about the same mark level.

2. Measuring the Circumference

Some might find measuring the circumference of an exercise ball with a long tape measure more handy, so here’s the chart for your reference:

【Tip】If your exercise ball does not reach the exact height/diameter or circumference, don’t panic! Please kindly know that it is normal for it to fall within a certain range (please refer to the Size Chart) rather than be the exact desired size. Take a 65 cm Trideer exercise ball (or 26"), its diameter falls between 58-65 cm / 23-26 inches upon full inflation. If it falls under the range, please re-inflate again until it reaches somewhere within the range.

On the other hand, just like overeating can lead to indigestion, over-inflation can potentially lead to problems of use or unwanted injuries, so please take care of your yoga ball by never inflating it to a size more than it should be.

The SIMPLEST Way to Measure

Got no tool to measure? No worries! You’ve got your best tool available -- you!

Here’s the Golden Rule:

Hips & Knees ≥ 90°+ Upper Body Upright when sitting on the exercise ball

Knees at 90 degrees is the minimum requirement for a yoga ball in order for it to work for you.

When Should I Choose a Larger Size?

Choose a LARGER ball if any of the following applies:

1. body weight / height proportion > average
This is quite intuitive as the Extra Weight would compress the exercise ball down more than usual, compromising your body alignment.

2. Legs Longer than average
Longer legs make your knees higher than your hips, easily resulting in a rounded back.

3. Using the yoga ball as a Chair Alternative

4. Back Problems

Comfort is the top concern when you use the exercise ball as a chair, yet a fully inflated exercise ball (to its maximum diameter) is too firm for you to sit on for an extended period. Therefore, choosing a larger yoga ball may be wiser as you can deflate a tiny bit and still maintain a good posture, which is key to relieving your back problems.

Note: The maximum height of your yoga ball chair should be no less than 4 inches higher than your regular chair.

5. Height is near the Upper Range

6. Novice Exerciser

A larger exercise ball means more contact area with the floor and your body, thus providing more stability and support during your workouts. If you have just embarked on your workout journey or have poor balance, then a larger yoga ball is a better option to start with.

7. If in Doubt
If you can’t decide between two close sizes, choose the larger one. You can always deflate the exercise ball later.

Should I Make the Exercise Ball Harder or Softer?

Go for Harder:

If you are up for a challenge in balancing and stabilizing, add more air in to decrease the contact area of the exercise ball with the floor.

Go for Softer:

If you are a novice exerciser, deflate a little so the yoga ball is more stable and you do not have to work your muscles as hard.

If you just gave birth, deflate your birthing ball as well since your pelvic floor is quite sensitive during this delicate postpartum period and a softer ball will make your seat more comfortable than a regular chair.

Other Factors to Consider

The exercise ball should not sink more than 6 inches / 15 cm when you sit on it. Such a degree of sinking means you either bought a yoga ball that is too large but under inflated, or the exercise ball needs re-inflation.

Press on a fully inflated yoga ball with your finger, and it should compress about 2 inches / 5 cm.

Go have fun!

Now you’ve got the correct ball size, it’s time to make the most out of your Trideer exercise ball ! Let us know how it goes - we value your voice and embrace any comment from you.