How the plate math works
Every barbell weight is the bar, plus the collars, plus the same plates on both sides. So the calculator starts with what is left after the bar and collars, halves it and finds the plates for one side. It works the same for the bench press, squat, deadlift or any other barbell lift.
Example: 315 lb on a 45 lb bar leaves 270 lb, or 135 lb per side. That is three 45 lb plates on each side. In kg, 100 kg on a 20 kg bar leaves 80 kg, so 40 kg per side: a 25 and a 15.
The calculator does not just grab the biggest plate that fits. It checks every mix of the plates you turned on and picks the one with the fewest plates. That matters when a plate size is missing: with only 25 and 20 kg plates, 40 kg per side is two 20s, not a 25 and something that does not exist.
When the weight does not add up
The smallest plate sets the step. With 2.5 lb plates as the smallest, the total can only change in steps of 5 lb, because each side gets the same plate. If your target falls between two steps, the calculator shows the nearest weight you can load and the one on the other side, so you can pick.
- Need smaller steps? Turn on fractional plates such as 1.25 lb or 0.5 kg if your gym has them.
- Mixed gym? Choose the unit of the plates. A 20 kg bar works on the lb setting too: the calculator converts it. For other weights, use the weight converter.
Loading the bar
- Heaviest plates first: big plates go on the inside and small ones outside. The IPF rulebook requires this order in powerlifting meets, with the heaviest discs innermost.
- Load both sides evenly: add plates to one side and then the other, so a bar in a rack does not tip.
- Lock them on: put collars on the bar before you lift.
In IPF powerlifting competitions, 25 kg discs are red, 20 kg blue and 15 kg yellow, and the collars weigh 2.5 kg each. The drawing uses those colors for kg plates. Plan your training weights first with the one rep max calculator, then load each set here.
How to use the plate calculator
- 1Choose lbs or kg for your plates and type the total weight you want to lift, bar included.
- 2Pick your bar, add the collar weight if your collars are heavy, and turn off any plates your gym does not have.
- 3Load the plates shown for each side, heaviest first. If the weight is not possible, load the nearest one or tap it to switch.
Frequently asked questions
How do I work out the plates for a barbell?
Take the target weight, subtract the bar and the collars, and halve what is left. That is the weight for each side. Then load the heaviest plates first and fill up with smaller ones. For 225 lb on a 45 lb bar: 225 − 45 = 180, so 90 lb per side, which is two 45 lb plates.
What if my weight cannot be loaded exactly?
Then the calculator shows the nearest weight you can load with the plates you have, below or above, and how far it is from your target. Add a smaller plate size to your list if you have one, or load the nearest weight instead.
Do collars count toward the weight?
Only if you enter them. Collars with real weight add up, so type the weight of one collar under Collars, and leave it at 0 for clips you want to ignore. In IPF powerlifting competitions, collars weigh 2.5 kg each, and the bar and collars together weigh 25 kg.
Can I use kg plates on a lb bar?
Yes. Pick the unit of your plates, then choose the bar in either unit or type its weight under Custom. The calculator converts the bar and works out the total in the plate unit, with the other unit shown beside it.
In what order should I load the plates?
Heaviest plates go on first, closest to the middle of the bar, with smaller plates outside. The IPF rulebook asks for this order in competition, so the referees can read the weight on each plate. The calculator lists and draws the plates in that order.