Have you ever come across a lifter who is turning a dial or pulling a pin before picking up a dumbbell only to ask yourself, “How do adjustable dumbbells work?”

Adjustable dumbbells are the fitness equipment industry’s response to customers wanting to save space and their wooden or tile floors from heavy steel and iron dumbbells.

Although it might look complicated, an adjustable dumbbell set with a rack is relatively easy to use. Let’s take a closer look at how adjustable dumbbells work, the pros and cons of these dumbbells, and whether they are worth buying.

Anatomy of Adjustable Dumbbells

Every type of adjustable dumbbell is going to have the same basic layout:

Bar / Handle: Typically made from steel, the bar or handle is the center of an adjustable dumbbell. On either side of the bar, you’ll find an extended piece of material – usually metal – that holds external weight plates. (Just like the ones pictured below.) 

External Weight: The external weight that can be used with an adjustable dumbbell depends on the type it is. Some adjustable dumbbells have loose weight plates, a miniature version of what you’d use with barbells. Others will have uniquely shaped weight plates that are locked into place with a turn-and-hook mechanism. More on this below.

How Do Adjustable Dumbbells Work?

How adjustable dumbbells work primarily depends on the type you’re using: traditional vs. modern adjustable dumbbells.


Have you ever walked into a friend’s garage (or maybe your own) and tripped over a stack of small weight plates and steel bars? This is the old-school adjustable dumbbell.

Depending on how much resistance you needed, you would simply unscrew the fasteners on each end of the handle and add or remove small-weight plates.

There’s not much to these OG adjustable dumbbells. Not surprisingly, their simplicity inspired numerous homemade substitutions involving broomsticks and trash bags filled with water.

Despite its simplicity, the traditional adjustable dumbbell is straightforward and durable. Spending the extra money on a steel handle and rubber-coated plates gives a bit more life to your weightlifting equipment


Let’s face it, traditional adjustable dumbbells lacked convenience, variety, and an overall WOW fitness factor. Seeing an obvious need, many fitness brands got to work to create a modern adjustable dumbbell, something more efficient than its predecessor.

Nowadays, the best adjustable dumbbells are almost exclusively based on the turn-and-hook model. All of the external weight plates are settled in a sturdy base in a pyramid-style order from lightest to heaviest.

The external weight plates are placed on the bar handle simply by turning a crank or switching a pin. The days of unscrewing the fastener, throwing weights off, and putting weights on are long gone with the introduction of modern adjustable dumbbells.

Two of the best examples of modern adjustable dumbbells would be the BowFlex 1052 dumbbells and the Power Block Pro Series dumbbells. 

Pros and Cons of Adjustable Dumbbells

Let’s take a closer look at the great things about adjustable dumbbells along with why you might want to avoid buying them.


Upfront Cost: Let’s say you wanted to buy enough dumbbells to get you started and support you throughout the next several years of your fitness journey. A set of 5 to 60 pounds would be sufficient for most. With this in mind, the initial cost of adjustable dumbbells makes them attractive.

A single adjustable dumbbell will vary in price, depending on the brand, locking mechanism, and materials used. However, in general, you can expect to pay between $400 and $500 for a single adjustable dumbbell that ranges from 5 to 60 pounds or a collection of adjustable dumbbells that total the same amount.

For example, you might buy a pair that goes from 5 to 30 pounds and another pair that goes from 30 to 60 pounds.

Space Saver: The modern adjustable dumbbells are surprisingly convenient for those who lack space in their homes. Having trouble visualizing how much space you’ll need for adjustable dumbbells? Put it this way: you just need enough room for a small to medium-sized microwave.

Given how little space these dumbbells take up, you can easily store them in a closet, under a raised bed, or behind a couch, to provide a few examples.


Equipment Malfunction: More moving pieces present a greater chance for malfunctioning and it doesn’t take long to find dozens of user reports on modern adjustable dumbbells failing during use. The most common malfunction of an adjustable dumbbell is the failure of the locking mechanism to engage. As luck would have it, this usually tends to happen to most people once their warranty expires, resulting in a costly repair.

Risk of Injury: Continuing with the point above, if an external weight plate has not been properly engaged and locked into place, you run the risk of getting hurt. For example, a weight plate can fall on your head or foot. A 20-pound dumbbell plate crashing on your foot can do some serious damage.

Not to Be Handled Rough: Unlike fixed dumbbells that can be tossed on the ground after a heavy set, you cannot drop or throw adjustable dumbbells. This eliminates a lot of the fitness population from using them, especially powerlifters who are constantly aiming for a new one-rep maximum. If you drop adjustable dumbbells, you are guaranteed to break them, and some warranties won’t cover anything outside of mechanical failure due to manufacturer defects.

Awkward Hold: The first thing you’ll notice when using adjustable dumbbells is how awkward they feel when compared to fixed dumbbells. What’s more, depending on the brand and length of the handle, you won’t be able to perform some exercises. For example, a longer bar handle will not allow you to properly execute a supinated bicep curl.

Fixed Dumbbells vs. Adjustable Dumbbells

Convenience is great but simplicity still might be preferable for some, and this is where fixed dumbbells come into play. While a set of fixed dumbbells might require more space and a bigger upfront cost, they are going to be the better investment for several reasons:

The Real Price: While fixed dumbbells might be more expensive in the beginning, they are almost guaranteed to last longer than adjustable dumbbells because of how they are made. While you are paying for repairs on your adjustable dumbbells, your fixed dumbbells are a one-and-done payment. So, the real cost of fixed dumbbells is lower than adjustable dumbbells in the long run.

Durability and Longevity: Fixed dumbbells are solid pieces of steel or iron, finished with a powdered coating that’s so tough, it’s placed on industrial machinery. Case in point, fixed dumbbells are built to take one hell of a beating, which is why you can throw and drop them, and you won’t find a scratch. This high level of durability is going to ensure that your fixed dumbbells are around for many years. Try doing the same thing with adjustable dumbbells… It won’t turn out well.

Reliability: Fixed dumbbells are one solid piece of metal. There’s no turning or cranking the dumbbells; you just pick them up and use them. They are simple and they are reliable. Adjustable dumbbells, on the other hand, require you to put them down, turn the dial, pick them up, and repeat. What’s more, there is always the risk of malfunction in the dialling mechanism, and it’s not a matter of “if” but a question of “when?” 

Are Adjustable Dumbbells Worth Buying?

If you have extremely limited space and a tight budget, adjustable dumbbells might be your only option. However, given their reliability and longevity, we highly recommend sticking with fixed dumbbells.

While modern adjustable dumbbells might give the illusion of progress, any experienced weightlifter will tell you that the industry has taken a step back. Why? What adjustable dumbbells make up for in space-saving, they lack in usability and reliability.

They’re awkward and fragile. If you’re serious about your workouts – regardless of your goals – you want fitness equipment that is going to be tougher than you. That’s why, for our money, fixed dumbbells will always be the way to go.