What goes on each side of the bar, in bumpers, drawn to scale.
Bumpers, exact. 25kg is 58mm thick, 20kg 50mm, 15kg 39mm and 10kg 35mm, all 450mm across, as published by Eleiko for their IWF competition disc. That is why only the colour tells the big four apart on the bar.
The sleeve, exact. 415mm a side, and a 20kg bar 2200mm long, from the IWF technical rules. A collar still goes on after the last plate, so the warning here says "before the collar" rather than pretending all 415mm are yours.
Change discs, approximate. The IWF gives their diameters and nobody publishes their thickness, so those four figures are estimated from the diameter and are the only estimates on this page. They shift the total by a few millimetres and never decide whether a load fits.
A gym set is not a competition set. Training bumpers are often thicker again, so if the answer here is close to the limit, measure yours.