Barbell plate math: which plates to load for any weight
A plain method for working out which plates go on each side of a barbell, with worked examples and reference tables in kilograms and pounds.
November 11, 2026 · 6 min read
Loading a barbell is a small subtraction problem that most people solve under time pressure, between two sets, with someone waiting for the rack. The method below takes about ten seconds once it is a habit, and it works for any bar and any set of plates.
Know your bar first
The number in your program is the total weight: bar plus plates. So the first thing to know is what the bar weighs.
| Bar | Kilograms | Pounds |
|---|---|---|
| Standard Olympic bar | 20 kg | 45 lb |
| Shorter, thinner Olympic bar | 15 kg | 35 lb |
These are the two most common bars, but not the only ones. Trap bars, EZ curl bars, safety squat bars and fixed machines vary a lot by manufacturer. If a bar is not marked, ask the gym staff or weigh it once and write the number down.
Know your plates
A typical kilogram set contains 25, 20, 15, 10, 5, 2.5 and 1.25 kg plates. A typical pound set contains 45, 35, 25, 10, 5 and 2.5 lb plates.
Not every gym has every size. Many kilogram gyms stop at 20 kg plates, and plenty of pound gyms have no 35s. The method stays the same; you only skip the sizes you do not have.
The method: subtract, halve, largest first
- Subtract the bar from the target weight. What is left is the total weight in plates.
- Halve it. That is the weight to load on each side.
- Take the largest plate that fits, as many times as it fits, then move to the next size down until nothing is left.
Loading the largest plates first puts the heavy plates closest to the middle of the bar and uses the fewest plates.
Worked examples
100 kg on a 20 kg bar. 100 minus 20 is 80. Half of 80 is 40 per side. The largest plate that fits is 25, which leaves 15. A 15 kg plate finishes it. Each side: 25 + 15.
If the gym has no 25s, the same 40 kg per side becomes 20 + 20.
72.5 kg on a 20 kg bar. 72.5 minus 20 is 52.5. Half is 26.25 per side. One 25 leaves 1.25. Each side: 25 + 1.25.
60 kg on a 15 kg bar. 60 minus 15 is 45. Half is 22.5 per side. One 20 leaves 2.5. Each side: 20 + 2.5.
185 lb on a 45 lb bar. 185 minus 45 is 140. Half is 70 per side. One 45 leaves 25. Each side: 45 + 25.
155 lb on a 35 lb bar. 155 minus 35 is 120. Half is 60 per side. One 45 leaves 15, a 10 leaves 5, a 5 finishes it. Each side: 45 + 10 + 5.
Weights you cannot load
Plates go on in pairs, so the smallest step you can make is twice your smallest plate. With 1.25 kg plates, the bar moves in steps of 2.5 kg. With 2.5 lb plates, it moves in steps of 5 lb.
If the per-side number does not come out as a sum of the plates you have, the target is not loadable with that set. Round to the nearest weight that is, and write down what you actually lifted rather than what the plan said.
Quick reference: kilograms, 20 kg bar
| Total | Per side | Plates per side |
|---|---|---|
| 40 kg | 10 kg | 10 |
| 50 kg | 15 kg | 15 |
| 60 kg | 20 kg | 20 |
| 70 kg | 25 kg | 25 |
| 80 kg | 30 kg | 25 + 5 |
| 90 kg | 35 kg | 25 + 10 |
| 100 kg | 40 kg | 25 + 15 |
| 110 kg | 45 kg | 25 + 20 |
| 120 kg | 50 kg | 25 + 25 |
| 140 kg | 60 kg | 25 + 25 + 10 |
| 160 kg | 70 kg | 25 + 25 + 20 |
| 180 kg | 80 kg | 25 + 25 + 25 + 5 |
| 200 kg | 90 kg | 25 + 25 + 25 + 15 |
For a 15 kg bar, add 2.5 kg to each side to reach the same total.
Quick reference: pounds, 45 lb bar
| Total | Per side | Plates per side |
|---|---|---|
| 95 lb | 25 lb | 25 |
| 115 lb | 35 lb | 35 |
| 135 lb | 45 lb | 45 |
| 155 lb | 55 lb | 45 + 10 |
| 185 lb | 70 lb | 45 + 25 |
| 205 lb | 80 lb | 45 + 35 |
| 225 lb | 90 lb | 45 + 45 |
| 245 lb | 100 lb | 45 + 45 + 10 |
| 275 lb | 115 lb | 45 + 45 + 25 |
| 315 lb | 135 lb | 45 + 45 + 45 |
| 365 lb | 160 lb | 45 + 45 + 45 + 25 |
| 405 lb | 180 lb | 45 + 45 + 45 + 45 |
For a 35 lb bar, add 5 lb to each side to reach the same total.
Collars
Spring clips and light plastic collars weigh very little, and most people leave them out of the count. Competition collars are different: they weigh 2.5 kg each, so the pair adds 5 kg and has to be counted.
With a 20 kg bar and competition collars, the starting weight is 25 kg. For 100 kg: 100 minus 25 is 75, half is 37.5 per side. Each side: 25 + 10 + 2.5, then the collar.
Whichever way you count, count the same way every session. A log is only comparable with itself if the convention never changes.
Mixed kilogram and pound gyms
Some gyms have a kilogram bar and pound plates, or a mix of both on the same rack. A few numbers help:
- 1 kg is about 2.2 lb.
- A 20 kg bar is about 44.1 lb, so it is close to a 45 lb bar but not identical.
- A 45 lb plate is about 20.4 kg. A 25 kg plate is about 55.1 lb.
The safe way is to convert every piece to one unit and add them up. A 20 kg bar with one 45 lb plate per side is 20 + 20.4 + 20.4, which is about 60.8 kg, or about 134.1 lb. That is neither a clean 60 kg nor a clean 135 lb, and it is worth recording the real figure.
Always read the number and the unit printed on the plate; colour alone is not a reliable guide across brands.
Letting a calculator do it
The arithmetic is simple, but it is easy to get wrong when you are tired. Quintal, an iPhone lifting log, includes a plate calculator that draws the bar as it should be loaded for the weight you enter, in kilograms or pounds.
The same subtraction is behind every ramp-up before a heavy set; see how to plan warm-up sets for that arithmetic. And if you want to compare what you loaded today with a set done at a different rep count, an estimated one-rep max gives you a common scale.
This guide is general information, not medical or personal training advice. Ask a qualified professional about your own situation.