How barbell plate loading is calculated
A loaded barbell is the bar plus two identical stacks of plates, one on each end. So the arithmetic is always the same three steps, whatever the weight.
1. Take the bar off the total
plate weight = target weight − bar weight
2. Halve it, because the bar has two ends
weight per side = plate weight ÷ 2
3. Make that figure from the plates you have
fewest plates that add up to the weight per side
For 142.5 kg on a 20 kg bar: 142.5 − 20 = 122.5 kg of plates, which is 61.25 kg per side, and that comes out as 25 + 25 + 10 + 1.25.
Loads people look up most
Every row below is what this calculator returns for that weight on a standard bar.
| On the bar | Bar | Each side |
|---|
| 60 kg | 20 kg | 20 |
|---|
| 80 kg | 20 kg | 25 + 5 |
|---|
| 100 kg | 20 kg | 25 + 15 |
|---|
| 142.5 kg | 20 kg | 25 + 25 + 10 + 1.25 |
|---|
| 200 kg | 20 kg | 25 + 25 + 25 + 15 |
|---|
| 185 lb | 45 lb | 45 + 25 |
|---|
| 225 lb | 45 lb | 45 + 45 |
|---|
| 315 lb | 45 lb | 45 + 45 + 45 |
|---|
How much does the bar weigh?
A standard Olympic barbell is 20 kg, or 45 lb. The women’s Olympic bar is 15 kg, or 35 lb, and is shorter with a thinner grip. Lighter training and technique bars are usually 10 kg or 15 lb. If you compete, spring collars weigh very little but competition collars are 2.5 kg each, so a bar with them on starts at 25 kg rather than 20. Set the bar weight to 25 in that case, because the calculator has no way to know.
Fixed-weight barbells, EZ curl bars and trap bars vary a lot between manufacturers and are often unmarked. If you are not sure, weigh the empty bar rather than assuming.
What if the gym is missing a plate size?
Untick it. The loading is recalculated around whatever is left, and it searches every combination rather than taking the heaviest plate that fits each time. That difference is not academic. Say you want 80 kg on a 20 kg bar, which is 30 kg a side, in a gym stocked with 25s, 20s and 15s only. Reaching for the 25 first leaves 5 kg to find and nothing to find it with, so a calculator working that way reports the weight as impossible. It is not: 15 + 15 loads it exactly.
When a weight genuinely cannot be made, you get the closest loadable weight below it and the size of the gap, rather than an error. What is not modelled is how many pairs of each plate the gym owns, so a loading can occasionally ask for four 20s a side when there are only two on the rack.
Why the plates go on in that order
Heaviest first, working outward from the collar. This is partly convention and partly mechanics: the largest plates sit against the shoulder of the sleeve where they are best supported, and loading them in a consistent order makes it obvious at a glance whether both ends match. It also means adding weight for the next set only involves the small plates on the outside.