Bumper plates come in a few standard sizes and are sold in pounds with kilogram conversion listed. All Fringe Sport bumpers are sold by the pound, and are great for beginners, experts, and everyone in between. Here is a chart with rough pound and kilogram weights: Bumper WeightBest Weight For: 10 lbs ~ 5 kgGreat for teaching or learning Olympic lifts. 15 lbs ~ 7 kgSame uses as the 10s, but this offers greater durability at only a slightly heavier weight. 25 lbs ~ 11 kgA very popular weight as they are very durable and throwing these on an Oly bar gives you 95 pounds (Fran Rx). 35 lbs ~ 16 kgA great size for adding more weight on the bar. 45 lbs ~ 20 kgThe most popular size for gyms - 45's really let you load up your bar and make some serious strength gains. 55 lbs ~ 25 kgWhen the 45s just don't cut it, we have 55lb bumpers to add some serious weight to the bar.