Barbell Plate Loading Calculator
Work out exactly which plates to load on each side of the barbell for any target weight in kg or lb.
Enter a target weight — the plates for each side are worked out as you type.
- Per side
- 25 kg × 1, 15 kg × 1
- Loaded total
- 100 kg
- Plates on the bar
- 4
- Match
- Exact
Plates available (pairs in your gym)
A pair is one plate for each side. Set a size to 0 pairs if you don't have it.
Warm-up ladder
| Set | Target | Loaded | Per side |
|---|---|---|---|
| 40% | 40 kg | 40 kg | 10 kg × 1 |
| 55% | 55 kg | 55 kg | 15 kg × 1, 2.5 kg × 1 |
| 70% | 70 kg | 70 kg | 25 kg × 1 |
| 85% | 85 kg | 85 kg | 25 kg × 1, 5 kg × 1, 2.5 kg × 1 |
| 100% | 100 kg | 100 kg | 25 kg × 1, 15 kg × 1 |
Loading numbers are arithmetic, not coaching: check every plate is seated and collared before you lift, and treat the warm-up ladder as a suggestion rather than medical or training advice.
How it works
A loaded barbell is symmetrical, so the calculator first works out the load for one sleeve:
per side = (target total − bar weight − 2 × collar weight) ÷ 2. It then searches
your plate inventory for the combination that hits that number with the fewest
plates, preferring the heaviest plate when two combinations tie. The search is a small
bounded-knapsack dynamic program over 0.25 increments, so it never over-reports a plate you
only own one pair of — unlike a plain greedy "biggest plate first" approach, which can miss an
exact match (40 kg a side from two 20s when you only have one 25).
When your target can't be hit exactly — say 101 kg with 1.25 kg as the smallest plate — the calculator loads the closest weight under the target and tells you how far short it lands, so you never accidentally lift more than you planned. The warm-up ladder repeats the same search at 40%, 55%, 70%, 85% and 100% of your working weight and rounds each set down to something you can actually load. Everything runs in your browser in plain JavaScript: no accounts, no ads, and nothing is uploaded.
Frequently asked questions
How do I work out the plates for a barbell?
Subtract the bar (and any collars) from your target weight, then halve what is left — that is the load for one sleeve. For 100 kg on a 20 kg bar that is (100 − 20) ÷ 2 = 40 kg a side, which the calculator loads as one 25 kg plate plus one 15 kg plate. Both sleeves must be loaded the same way.
What if my target weight cannot be loaded exactly?
The calculator loads the heaviest combination that stays under your target and tells you how far short it lands — for example 101 kg on a 20 kg bar with 1.25 kg as your smallest plate loads 100 kg, one kilo under. Add micro-plates (0.5 kg or 0.25 kg) to your inventory to close smaller gaps.
Does it handle my gym's plate set and both kg and lb?
Yes. Switch between kilograms and pounds at the top, then open "Plates available" and set how many pairs of each size you own — set a size to 0 pairs and the calculator routes around it. It searches for the fewest-plate combination rather than grabbing the heaviest plate first, so it still finds an exact match when the big plates run out.