Shopping for a barbell? You have probably noticed that barbells have different weights. The most common are 15 kg. (35 lbs.) and 20 (45 lbs.). What’s the difference and what’s best for you? Here are the differences and what you have to know to decide.
The differences in bar weight are the result of Olympic standards. Women’s Olympic barbells weigh 15 kg (33 lbs.) while men’s Olympic bars weigh 20 kg (45 lbs.). Length, shaft diameter, load capacity and knurling are also different. For most people a 20 kg/44 lbs. is the best choice. Exceptions are if you have limited space and/or smaller hands.
Below we’ll dive into all the differences into great detail.
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What’s the difference between 15 kg and 20 kg bars?
Let’s take a look at what the difference is between the barbells of different weights. Before we get into the details, it’s important to know where the differences originate.
Below you’ll find some words not everyone is familiar with, related to parts of a barbell. Click here to find a post that explains exactly what all the parts of a barbell are.
The different weights come from the Olympic standards. You might not know this but the women’s and men’s Olympic barbells are different. The women’s barbells are slightly different than men’s barbells in quite a few ways.
While most barbells you buy for a random (home) gym aren’t intended to be used on an Olympic stage, they are still modeled after those two different standards.
That leads to quite a few differences;
|Men's Olympic Barbell||Women's Olympic Barbell|
|Weight||20 kg/ 44lbs.||15 kg/ 33lbs.|
|Total Length||2200 mm/ 86.6"||2010 mm/ 79.14"|
|Shaft length||1310 mm||1310 mm|
|Sleeve Length||16.25"/ 415 mm||12.5"/ 320 mm|
|Shaft Diameter||28 mm||25 mm|
|Knurling||Center Knurling||No Center Knurling|
|Load Capacity (Bumper Plates)||540 lbs./ 245 kg||360 lbs./ 163 kg|
Weight: The weight is obviously different. The men’s Olympic bar weighs 20 kg. Converting that to pounds will give you 44.092452437 lbs. Since that’s a bit specific, most barbells are advertised as 44 or 45 lbs.
Women’s Olympic barbells weigh 15 kg. which translates to 33.0693393278 lbs. Often these barbells are advertised as 33 lbs. or even 35 lbs. in imperial units.
Most barbells are just modeled after Olympic standards but aren’t actually within specification to be certified for Olympic use. However, these bars will be close enough to that weight for general gym use. 300 grams difference really doesn’t matter all that much in a non-competition setting.
The weight differences are the result of a few other differences between women’s and men’s Olympic bars.
Shaft length: The shaft length (length between the sleeve collars) is actually the same on women’s and men’s Olympic barbells. The length between the collars is 1310 mm. on both women’s and men’s Olympic barbells. That means the ways you can hold the different barbells are exactly the same ways.
Shaft diameter: Besides the weight, the other biggest difference in Olympic barbells is the shaft diameter. Men’s Olympic barbells have a 28 mm diameter shaft while women’s bars have a 25 mm diameter shaft.
The main reason for this difference is the difference in hand size between men and women. Men generally have bigger hands and therefore are more comfortable with a slightly bigger diameter bar.
Length: The official total length of a women’s Olympic barbell is 2010 mm. or 79.13386 inch. The total length of a men’s Olympic barbell is 2200 mm or 86.61417 Inch.
The standards are set in millimeters by the Olympic committee which is why the length in inches looks a bit messy. Often the lengths in inches are just rounded to 86.6” for men’s barbells and 79.14” for women’s bars.
Sleeve length: Since the total length is different but the length between the collars is the same, the sleeve length has to be different. And it is.
The loadable sleeve length for men’s Olympic barbells is 16.25” (415 mm)
The loadable sleeve length for women’s Olympic barbells is 12.5” (320 mm)
This is where the difference in lengths comes from between 15 and 20 kg. barbells.
Strength: With good manufacturing and engineering, the strength of a 15 kg. and 20 kg. barbell should be the same. The tensile strength and whip should be very similar between the bars. There is likely more variability between two 20 kg. bars from different manufacturers than between a 15 and 20 kg bar from the same brand.
Load capacity: Since the sleeves are different lengths, the load capacities are also different. How much weight you can load on the bar depends on which type of plates you’re using. Some weight plates are thicker than others.
Bumper plates are thicker than most other plates. 45 lbs. bumper plates are 2.15” thick. Olympic collars are 3” Wide.
So that means you can fit the following on the different bars;
Men’s bar load capacity;
- Men’s bar loadable sleeve: 16.25”
- 16.25” – 3”(collar) = 13.25”
- 13.25”/2.15” = 6.16 plates. Obviously you can’t load 0.16 plates so you can fit 6 plates on one side. That means 12 plates on both sides.
- 12*45 = 540 lbs.
Women’s bar load capacity;
- Men’s bar loadable sleeve: 12.5”
- 12.5” – 3”(collar) = 9.5”
- 9.5”/2.15” = 4.42 plates. Obviously you can’t load 0.16 plates so you can fit 4 plates on one side. That means 8 plates on both sides.
- 8*45 = 360 lbs.
Those calculations are for bumper plates which are quite wide. If you’re just using cast iron plates, which are a lot narrower, you can fit a lot more weight.
For example, a 1.3” thick cast iron 45 lbs. plate means you can fit 900 lbs. on a men’s bar and 630 lbs. on a women’s bar.
Knurling: The last difference between the two bars is the knurling. The knurling is the cross hatch pattern in the metal of the bar. The men’s (20 kg) Olympic barbell has knurling in the middle of the bar while the women’s (15kg) bar doesn’t have knurling in the middle.
The other knurling and knurling marks are the same. However, that is only applicable to barbells that are built to completely follow the Olympic standards. Many manufacturers don’t follow those standards to the last letter because they don’t have to since they are not aiming to build certified Olympic barbells. So for that reason you can find barbells that are 15 kg and do have center knurling.
Which weight barbell is best for you?
Above you can see all the differences between the 33 and 45 pound barbells. But what is actually good for you? Which one should you buy?
That depends on a few factors;
Hand size: The biggest difference you’re going to feel immediately is the diameter of the barbell. What is better for you depends on your hand size.
There is a reason why the women’s and men’s standards are different. That’s because hand size correlates very well with the genders. But of course it’s possible you have smaller or bigger hands than the average.
If you have smaller hands, a thick bar is going to be more difficult to hold on to. If you have bigger hands a smaller bar will feel uncomfortable since the weight is more concentrated on one spot.
So take a look at your hands and see what the best fit for you is.
Strength: How strong are you? If you want to go heavier, that’s easily solved with an extra plate. Making the bar lighter is not possible unless you attach helium balloons to it.
If you want to do exercises with a very light weight (lighter than 20kg), go for the 15kg barbell. However, this is a pretty small factor for most people. With a little bit of training, you’ll blow past the 20kg on every exercise very quickly.
Gym size: How big your gym is also plays a role. 15 kg. bars are a few inches shorter. In a small space, that can make the difference between being able to use it or not.
You want to leave about 5 inches from the end of the bar to the wall/other equipment at the minimum. If your walls are close together make sure to measure and see which bar is the better fit.
Exercise selection: Men’s bars have center knurling, women’s bars don’t. Why is that important? Mainly for back squats. It keeps the barbell in place during squats. Since most people will be using their bar for squats in a home gym, it’s good to have a center knurl.
One big caveat here: Many manufacturers don’t completely follow the Olympic standards. Since they know most people will benefit from center knurling most 15 kg. bars will have it as long as they’re not certified by the International Weightlifting Federation (IWF).
That means it’s absolutely possible to get a 15 kg bar with center knurling. Just pay attention when you’re shopping for one.
What about different weight barbells?
The two barbells above are the two most common sizes and weights. However, there are plenty more different barbells available although most of them are not as common.
Many barbells that are different are built for a specific goal. Where the standard Olympic barbells can be used for many different exercises, most other barbells are just used for a few movements. Deadlift bars for deadlifts, EZ curl bars for curls, etc.
So they are different and have different weights. However, if you’re looking for a barbell for general use, the specialty bars aren’t suitable. If you want to improve that specific lift, a specialty bar can be a great addition to your gym.
One honorable mention goes to the 6’ straight barbell. It’s very similar to the ‘standard’ Olympic barbells but just a little shorter.
In a small home gym, a 6’ barbell can be very useful. It’s a bit lighter and shorter than the women’s Olympic barbell so you can use it in a smaller space without bumping into the walls.
I’ve written a whole post about what you have to know about using a 6’ barbell effectively in a home gym. Click here to find it.
There are a few differences between 6’ and the longer ‘standard’ Olympic bars.
- Weight: A shorter bar means less metal is used to make it which in turn means it’s lighter. There are no standards for 6’ bars so they’re available in different weights. Most 6’ barbells weight around 30 lbs. /13.6 kg. but they can vary a few lbs.
- Diameter: Most 6’ barbells have a 28mm shaft diameter.
- Load capacity: Since the sleeves are likely cut short, you won’t be able to load as much weight on it as a full sized barbells.
- Length: Obviously the length is different but let’s get into it a little deeper;
6’ barbells are obviously shorter but how do manufacturers make that happen? There are two ways to save length;
- Shorten the shaft (between the sleeves)
- Shorten the sleeves
Or it’s possible to both shorten the shaft and sleeves.
Being able to use it in a smaller home gym seems to be just a benefit but there is a catch. If the shaft of the barbell gets too short, it won’t fit on your power rack. Most power racks are about 49” wide. That means to be able to rack the barbell, you need at least 50” of shaft length between the collars. Many 6’ barbells shorten the shaft too much which causes them to be useless for general use in a home gym because they don’t fit on the power rack.
There are 6’ barbells that just shorten the sleeves without shortening the shaft too much.
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