Barbell plate calculator
Enter the weight you want on the bar and see exactly which plates to load per side, with a diagram of the loaded barbell. The calculator searches every combination your plates allow instead of just stacking the heaviest first, so it still finds the exact weight when your gym is missing sizes.
How the math works
The bar counts toward the total, so the plates only cover the difference: target weight minus bar, split equally between the two sides.
From there the calculator searches combinations and returns the one with the fewest plates. That matters more than it sounds: the naive approach of stacking the heaviest plate that still fits misses exact loads. If your gym only has 25s and 10s and you need 30 kg per side, that approach loads a 25 and stops 5 kg short, even though 10+10+10 hits it exactly. This one does not make that mistake.
Small habit, fewer ruined sets
Misloading the bar is the most common silent error in the gym, especially in a rush between sets. Knowing the per-side breakdown before you touch the plates removes the arithmetic at the moment you are most tired. The warm-up sets calculator gives you the ramp weights to load, and inside the APX app your working weights come from your own log, so the target is never a guess.
Method and sources
There is nothing to model here beyond arithmetic, so the only external source is the equipment specification: which bars and plates count as standard, and why they are coloured the way they are.
- International Weightlifting Federation. Technical and Competition Rules & Regulations: barbell and disc specification. IWF, section 4 (Equipment) Used for: bar weights (20 and 15 kg), plate denominations and the colour coding used in the diagram
Frequently asked questions
Subtract the bar weight from your target weight and halve it: that is what goes on each side. For 100 kg on a 20 kg bar that is 40 kg per side, either two 20s or a 25 plus a 15. This calculator searches every combination your plates allow and returns the one using the fewest plates.
A standard Olympic barbell weighs 20 kg (45 lb), and the women's Olympic bar weighs 15 kg (35 lb), per IWF specification. Many gyms also have lighter training bars. Specialty bars vary: check the label, because assuming the wrong bar shifts every set by several kilograms.
Untick a size you do not have, or set how many of each you can actually get per side. The calculator rebuilds the load from what remains. If the exact target cannot be built, it loads the closest weight below and shows the gap: round down, keep the reps.
The same weight can be built several ways: 40 kg per side is both 25+15 and 20+20. The calculator shows the combination with the fewest plates and picks the first one when several tie. Any combination summing to the same per-side weight is equally correct.
That is the IWF colour code used in weightlifting and most gyms: 25 kg red, 20 kg blue, 15 kg yellow, 10 kg green, 5 kg white, 2.5 kg small red, 1.25 kg chrome. Colour is faster to recognize than the number stamped on the rim.
Know your numbers before you load
APX keeps your working weights and history, so every session starts with the right target.
Download APX free