Olympic Plate Diameter – Inside and Outside Dimensions
The overall, or outside, diameter of an olympic plate is 450mm (17.72″). This is the IPF (International Powerlifting Federation) and IWF (International Weightlifting Federation) regulation size.
This goes for most models of olympic plates, including:
- Bumper Plates – Solid rubber plates used for the clean-and-jerk and the snatch in Crossfit and olympic weightlifting.
- Powerlifting Discs – Solid steel calibrated plates used in powerlifting competitions
- 45lb+ Cast Iron Plates – Some 45lb and 100lb cast iron plates are made to the 450mm spec. This includes rubber or urethane coated plates that are only coated on the surface and are mostly cast iron. But models can vary from 430mm to 470mm.
Are they always these sizes?
Unfortunately not. I’ll explain.
There are two reasons for this specification:
- The bar shaft is sitting at an exact height of 211mm (assuming a 28mm diameter shaft) from the floor when the lifter begins a lift such as a deadlift or clean. .This is important for competition purposes. If you’re not competing, this doesn’t necessarily matter a whole lot. It also makes no difference for exercises like the bench press.
- Dropping the barbell is rough on plates, and if all the plates don’t reach the floor, the ones taking the shock load might not be able to handle it and can break. Even bumper plates are only engineered to take a little more than their own weight when dropped.
- If only some plates are touching the floor and there’s any slack in the hole sizing on them, you’ll end up with a jerky pull as you’re lifting some weight while still pulling slack out of the rest of the weights. Think of it like a coupler connecting railway cars, which is good for the engine because it can gain momentum as it pulls the slack out of each car at a time before it pulls the weight of all the cars, but it’s bad for you as a lifter because you need a smoother pull.
Some people gather plates over the years for their gyms and aren’t always able to get the same brand and model of plates each time. The odds of getting two brands of plates of a non-standard diameter to match up are pretty hopeless. However, if it’s 450mm diameter, your odds of getting some matching plates drastically improve.
Our 45 lb economy plates are measured at 451mm. These are what are included in our lowest priced 300 lb olympic weight sets.
Any cast iron plate 35lb or lighter will be smaller. The diameters are only the same for 45lb and 100lb (when the particular model is even made in a 100lb size) plates.
Bumper plates are all the same diameter, regardless of weight, and only vary in thickness. They are more targeted towards the olympic lifting market, so the IWF specification is taken more seriously and they tend to meet the 450mm spec. Even so, Hi-Temp bumpers and some other brands like some of Rage Fitness’ bumpers are more like 17.5″ or 440mm.
Hole Size / Inside Diameter
In a perfect world, all olympic plates would at least have the same sized holes. That isn’t always the case.
You can’t fit a 2″ rod into a 2″ hole, so good Olympic bars have 50mm (1 31/32″) sleeves, and good Olympic plates have holes just slightly larger than 50mm, such as 50.4mm or 50.8mm (2.0″).
What happened at some point was manufacturers started making cheaper olympic plates with holes a little larger than 2″. That way plates with casting defects in the holes would still fit the bars. So they have a very sloppy fit, which is annoying for any type of lift you do off the floor, such as deadlifts, cleans or snatches, because you have to pull the slack out.
Making matters worse, because their plates were so loose, the manufacturers making these cheap plates didn’t need to care about the bar sleeves being exactly 50mm, so they made the bar sleeves more like 2″ and sold them with their plates in weight sets. That worked out fine until customers wanted to fit high-quality plates on the cheap bar and found they were so tight they would get stuck.
Nearly all the olympic plates we sell on this website, and the olympic bars, are made for a snug fit. The exception is our “economy” plates that are clearly described on the product page as being a more sloppy fit than normal. Other fitness equipment retailers are often ignorant of the whole issue and just assume they’re the same, and they get confused if you try to tell them the fit is too sloppy or too tight on the equipment you bought from them. This is why it’s important to do your shopping with a company that understands what they sell.