Who knew working out involved so much math...

As great as strength training is for everything from your calorie-burn to your bones, sometimes it feels like a lot of math. First, you need to figure out how much the barbell weighs (wait, do you need to factor in those clip things, too?), then add up all of the weight plates on it, and then you can drop down into that barbell back squat. And if you're working toward your one-rep max? Might as well go get your bachelor's in math first.

But before you can even start crunching numbers, you need to know one very important thing: How much does the bar weigh that you're lifting?

ICYDK, you'll find a bunch of different types of bars at the gym, all weighing different amounts, and for different purposes. Here's the DL.

Types of Barbells At the Gym

Imagine trying to do a bicep curl with a full-size barbell—yep, that's just one reason different types of barbells exist. Different sizes and shaped bars allow you to weigh your movements in different and more efficient ways.

"Different types of barbells provide you with a different type of stimulus," explains Grayson Wickham, P.T., D.P.T., C.S.C.S., founder of the mobility and flexibility platform Movement Vault.

Take deadlifting with a traditional barbell and a trap or hex bar, for example: "With the traditional barbell deadlift, the bar (and weight) is directly in front of your body," says Wickham. As a result, lifting that bar fires up your posterior chain (the muscles on the back of your body), like your hamstrings and glutes. "With a hex or trap bar deadlift, though, you're essentially inside the bar, so the weight is directly at the center of your body," he says. Deadlifting from this position puts the focus on your quads.

Basically, the different barbell options at the gym help you mix up different movements and fire up different muscles. Here's what you need to know about how much each type of bar weighs—and why. (Related: Training Volume Basics If You're New to Lifting Weights)

How Much Each Bar Weighs

Note: Depending on the brand, the bar at one gym may weigh a different amount than the bar at another, even if they're the same type, says Wickham. Some brands mark a barbell's weight on the very end of the bar—but, when in doubt, check with a trainer to confirm how much it weighs before you start loading on the plates. (Then work on these essential barbell exercises everyone should master.)

Standard Barbell

Your standard straight barbell weighs 45 pounds, is about 7 feet long, and can be used for most lifts, including squats, deadlifts, bent-over rows, overhead presses, and even biceps curls, says Wickham.

Olympic Barbell

Like your standard barbell, an Olympic barbell also weighs 45 pounds and is about 7 feet long. The difference between the bars, though, is that Olympic bars have rotating sleeves (the parts that hold the weight plates), so you can use them for Olympic weightlifting moves like clean-and-jerks and snatches, says Wickham. (The rotating sleeves allow you to rotate the barbell easily throughout these complex movements without having to spin the weight as well.) Olympic bars are typically also slightly smaller in diameter (a.k.a. thinner), so that they're easier to grip throughout complex moves.

Women's Barbell

In many bigger gyms (and CrossFit boxes), you'll find 35-pound women's bars, which are thinner, lighter, and slightly shorter (about 6.5 feet) versions of your standard barbell. (You'll find both standard and Olympic versions of these smaller bars.) Since women often have smaller hands than men, these bars' smaller diameter makes them easier to grip, says Wickham. These lighter bars also make various moves more accessible to beginners and people you are beginning with less strength. Oh, and one more thing: Since there's less distance between the weight plates on a women's bar, you need less stability to safely perform whatever exercise you're doing, adds Wickham.

Trap or Hex Bar

Typically shaped like a hexagon with two weight sleeves coming out of the sides, trap or hex bars allow you to stand directly in the middle of the weight you want to lift. They typically range between 35 and 65 pounds, and can be used for deadlift variations, farmer carries, and trap shoulder shrugs, says Wickham.

EZ Bar

EZ bars, which have a W-like shape in the middle, usually weigh 20 to 40 pounds and are much shorter than a standard barbell. They are typically used for biceps curls, triceps exercises (like skull-crushers) and rowing movements—and allow you to vary your grip, according to Wickham. Switching up your grip means you can focus on different parts of a muscle group. (See: Close-Grip vs. Wide-Grip Bench Press)

Triceps Bar

Typically a smaller, simpler version of the multi-grip bar, triceps bars weigh between 20 and 40 pounds. They allow you to perform triceps moves (like skull-crushers) with a narrow, neutral grip (meaning your palms face each other), which Wickham says sets your triceps on fire.

Safety Squat Bar

Consider the safety squat bar a more intense contraption created from a standard barbell. Weighing in at 60 to 75 pounds, this bar has curved ends so the weight plates sit closer to the ground, making the weight easier to balance, explains Wickham. Two padded bars also jut out of the middle of the bar and wrap forward around your shoulders for you to hold onto. Though intimidating-looking, safety squat bars make back squatting easier for people with shoulder mobility issues or injuries who can't reach back for regular back squats. Plus, because of the lower weight plates, the safety bar also increases the demand on your quads during squats. (Related: Build Proper Squat Form with Squat Therapy)

Swiss or Multi-Grip Bar

Swiss or multi-grip bars can weigh between 35 and 55 pounds and are basically small metal ladders with bars coming out of each end. (Though shorter than standard barbells, they're longer than the next two bars on this list.) They're usually used to mix up your grip in upper-body exercises, such as the bench press, overhead press, and row, says Wickham.

Smith Machine Bar

The Smith machine features a barbell on a fixed movement path that you can perform a variety of moves using, such as bench presses, squats, lunges, and rows on, says Wickham. Depending on you gym's model, the bar alone weighs 30 to 55 pounds. Since the Smith machine bar moves on a fixed path, you don't need to use stabilizing muscles (like those in your core) to keep it balanced while you use the bar, explains Wickham. As a result, it often feels super light (and maybe even a little awkward) as you move it up and down its fixed track. That said, it's a safe place to start if you're new to lifting weights.

What About Weight Clips and Locks?

If you're wondering just how much the clip or lock you use to secure your weight plates on your barbell weighs, well, it depends. The simple springy metal clips you'll find at many gyms weigh just about a quarter of a pound, while heftier plastic or thick metal locks (also known as collars), can weigh closer to two pounds, according to Wickham.

If you're using light metal clips, don't worry about factoring them into your total weight. If you're using heavier metal locks or collars, though, you might as well give yourself credit for those few extra pounds.

Different Types of Weight Plates

Though different gyms may offer a slightly different potpourri of weight plates for you to add to your barbell, Wickham says that most stock the following weight plates: 2.5lbs, 5lbs, 10lbs, 15lbs, 25lbs, 35lbs, and 45lbs. (Powerlifting gyms and CrossFit boxes may also have 55-pounders.)

While most traditional weight rooms and box gyms are stocked with regular, round metal weight plates (which are sometimes coated black and octagonal in shape), CrossFit boxes and weightlifting gyms often stock colorful Olympic plates, a.k.a. bumper plates. (P.S. did you know you can do exercises with just the weight plates alone?)

"Olympic plates have a metal core with hard rubber coating on them so that you can safely drop the weight from various heights during Olympic lifts [like cleans]," says Wickham. If you were to drop a barbell with traditional plates on it from shoulder-height, the impact would damage the bar.