EXACTLY how much weight can a 45lb bar hold?

Barbell shopping can be confusing – working out which bar you need (or want) without blowing your budget is tough, and working out just how much weight a 45lb Olympic barbell can hold is down right tricky as all manufacturers seem report it slightly differently! Here’s what I’ve found out about weight capacity from trawling online:

Official weight limits will vary

Not all 45lb Olympic barbells are created equal, and not all published weight limits are comparable. For example some quote a static load – the amount a barbell can hold still – while others quote weights that can be moved or lifted with the bar.

What is the weight capacity of a good quality 20kg (or 45lb) Olympic barbell?

As an example of the variation in the Olympic Barbell marketplace, here are three popular, good quality 20kg bars and their respective weight capacities:

• Strength Shop 2028 Olympic Bar – rated to 250kg in use
• Rogue Ohio Bar – rated to around 500 – 550kg (not explicitly listed on site)
• ATX RAM Bar – rated to 700kg

So it is safe to say that the capacity of the barbell is unlikely to be a factor for many, if any, amateur lifters! Hopefully this means you can lift with peace of mind that your bar can take the strain…

What influences how much weight a barbell can hold

Barbell shafts are made of steel typically with a coating or finish to protect the metal from corrosion. On each end there is a sleeve that is loaded with plates. The sleeve can (or should) rotate – if it doesn’t rotate then it’s not a great sign!

The barbell shaft is the key piece that influences weight capacity. The two main properties that matter are:

1. Quality of steel
2. Amount of steel

Lets take a look at each in turn:

QUALITY of steel

I am far from a metallurgist but my understanding is that poorer steel will bend or break under a lower load than higher quality equivalent. In the barbell-world the closest to a reporting standard is the tensile strength of the metal.

If you use a lower quality steel you need comparatively MORE of it to lift the same weight as a higher metal would otherwise tolerate.

Quality barbells will typically be around 190k+ PSI. The famous Texas Power Bar is around 190,000 PSI, my ATX RAM bar is around 206,000PSI with the Rogue Ohio similarly around 205,000 PSI. 

Cheap or unbranded bars will often take the easy escape of simply NOT publishing a tensile strength or similar rating which makes comparing bars even harder for us. If you are unsure on the quality of the bar and can’t find this then consider it a red flag. Drop the supplier a message and see if they can help you out.

AMOUNT of steel

A 45lb or 20kg barbell should be 7ft in length. As the length is fixed the only variable that can influence the AMOUNT of steel in the shaft is the THICKNESS.

This is because if the quality of steel is otherwise identical, the thickness will determine the weight capacity of any bar.

High quality barbells will range in diameter from 27mm to 29mm. The thinner 27mm is reserved for deadlift bars where bar whip is a bit more desirable, while 29mm is for stiffer power bars. 28mm and 28.5mm bars are excellent choices for general training needs or hybrid bars.

Bars that are thicker than this typically indicate poorer steel quality. It is very common to find 30mm – 32mm unbranded chrome plated bars in the marketplace so be aware these are not the optimal diameter, nor exhibit the quality of metal you would hope for!

Budget bars often have LESS weight capacity

Poorer quality bars will deviate from the usual thickness range – often in the 30mm – 32mm diameter range as noted above. This is so they can use a lower quality steel, but make up for it in VOLUME used.

While a few millimetres of diameter doesn’t sound like much it is an indication of a lack of research in to proper bar specs, usually of poorer quality steel AND as a result can be harder to use due to being 10% – 20% thicker.

Standard 1” vs Olympic 2” barbells

In this article we are focused on the 45lb / 20kg Olympic barbells with sleeves designed to take weight plates with 2” hole diameters.

When shopping for home gyms equipment it is common to find 1”, or ‘standard’, barbells. These typically have reduced weight capacity with many topping out around 250lb – 300lbs. While this is fine for accessories it is unlikely to be enough for serious deadlifting or squats where you will race up to and likely through these figures in a few months of serious training.

While the same general rules apply around steel quality and thickness, these 1” standard bars are out of scope for this article. 

2” Olympic barbells are a bit more expensive than the 1” equivalent, BUT they are superior in a few key areas:

• Rotating sleeves
• Heavier build weighing 45lbs
• Uniform length at 7ft
• Better acting and knurling options
• Wider range of plates available including several sets that are more accurately calibrated

In other words, if you have space and budget an Olympic barbell will likely be a better investment over the long term. The standard size makes buying squat racks and other gym equipment easier, as well as letting you buy from a reputable manufacturer (the likes of Rogue et al don’t tend to entertain standard 1” bars). It’s also easier to pick up decent value plates with the Olympic 2” hole than the 1” equivalent. 

A quick note on barbells BENDING…

You could have the best quality Olympic barbell in the world, BUT it can still be bent fairly easily. Leaving a barbell LOADED with weight plates on a rack will bend most bars over time. Even relatively modest weights can bend them if left for long enough.

To prevent this simply empty your bar each time you finish up!

Conclusion

Barbells look simple – but they are complicated beasts! Even trying to pin down how much weight they can hold can be tricky – in my research above I found the weight capacity of a 45lb barbell to generally be 250kg – 700kg which is more than enough for MOST lifters. Buying a good quality bar from a respected manufacturer who KNOWS the sport will ensure you can lift safely for many years without worrying about overloading your barbell!