Plate calculator
Enter the total weight you want on the bar and see which plates go on each side, using the fewest plates your gym has. It also plans your warm-up sets.
Filled in with example values. Replace them with yours.
Bar, collars and plates20 kg bar · no collars · 7 plate sizes
| Reps | Weight | Per side |
|---|---|---|
| 10 | 20 kg | Just the bar |
| 5 | 40 kg | 10 |
| 3 | 60 kg | 20 |
| 2 | 80 kg | 25 + 5 |
| 1 | 90 kg | 25 + 10 |
| Top set | 100 kg | 25 + 15 |
How to load a barbell
The total weight on a barbell is the bar plus the plates on both sides. A 100 kg lift on a 20 kg bar leaves 80 kg for the plates, which is 40 kg on each side. Here that is a 25 and a 15 kg plate. The calculator does this for you and picks the combination with the fewest plates, so the bar stays short and quick to load. It also draws the loaded bar.
A few habits make loading safe and fast:
- Heaviest plates first. Slide the biggest plate on first so that it sits next to the bar’s center, and finish with the smallest on the outside. Competition rules ask for the same thing: the first and heaviest discs go on first.
- The same on both sides. One heavier side tips the bar mid-rep. Count the plates on each side before you unrack.
- Use collars. Plates can slide on the sleeve, especially on a pull from the floor or a bench press that is not perfectly level. A collar costs two seconds and keeps the load where you put it.
Barbell and plate weights in kg and lb
The bar is part of the load, and not all bars weigh the same. Plates are marked with their weight, and common sizes run from 1.25 to 25 kg or from 2.5 to 45 lb.
- Barbell (20 kg or 45 lb). The standard men’s bar in competition and in most gyms.
- Women’s bar (15 kg or 35 lb). Thinner and a little shorter, and the standard women’s bar in weightlifting.
- EZ bar. Curved for the wrists. Weights vary by model, usually around 7 to 10 kg. If yours says otherwise, choose Other and type it.
- Trap bar. Often 25 kg, but 20 to 30 kg is common. Check the label.
- Smith machine. The bar slides on rails and is often counterbalanced, so its weight varies widely. Many gyms print it on the machine. If not, treat the first rep as a test.
If you do not know your bar, put an empty bar on a scale or ask the gym. A wrong bar weight is a wrong load on every set.
Kilograms and pounds
Most gyms outside the United States have kilogram plates, and many American gyms use pounds. The numbers on the plates look similar and are not the same. A 45 lb plate is 20.4 kg, and a 20 kg plate is 44.1 lb. Calculators that convert 100 kg to 220.5 lb are right, but you cannot load 220.5 lb with pound plates, which move in steps of 5 lb with a 2.5 lb plate on each side.
That is why this calculator works in your unit. Switch to lb and it uses pound plates, the 45 lb bar and 5.5 lb competition collars. When you change unit, your weight moves to the closest loadable weight in the new unit.
Small plates and why they matter
Every plate goes on both sides, so the smallest step you can take is twice your smallest plate. With 2.5 kg plates the jump is 5 kg. With 1.25 kg plates it is 2.5 kg. With 1.25 kg and 0.5 kg plates together it drops to 0.5 kg.
For a lifter who presses 40 kg, a 5 kg jump is 12.5 % more weight. That is a big step for one workout, and it is one reason progress stalls on upper-body lifts. Small plates let you add weight in steps your body can follow. If your gym has fractional plates, switch them on under Your plates and the calculator will use them. If it does not, a pair of 1.25 kg plates costs little and is the cheapest upgrade for a home gym.
Muscla works on the same idea. It rounds the weight in your plan to what your plates can load, so a suggestion never lands on a weight you cannot build.
A few loads to check against
Doing it by hand a few times makes the numbers feel natural. Take off the bar first, then halve what is left.
- 60 kg on a 20 kg bar: 40 kg for the plates, 20 kg per side. One 20 kg plate on each side.
- 102.5 kg on a 20 kg bar: 82.5 kg left, 41.25 kg per side. That is 25 + 15 + 1.25.
- 140 kg on a 20 kg bar: 60 kg per side, which is 25 + 25 + 10.
- 135 lb on a 45 lb bar: 90 lb left, 45 lb per side. One 45 lb plate each.
- 225 lb on a 45 lb bar: two 45 lb plates per side. Lifters call this two plates.
When you add competition collars, take their 5 kg off as well before you halve the rest. The calculator shows the sum in one line under the plates, so you can check it against your own count.
When your plates are not the standard set
A home gym often has only a few sizes, and that changes the answer. With only 20 kg and 15 kg plates, 80 kg on the bar needs two 15 kg plates per side, because 20 kg plus 15 kg is too much and 20 kg alone is too little. Taking the biggest plate first does not always work, so the calculator searches all combinations and keeps the one with the fewest plates.
Some totals cannot be built at all. When that happens the calculator says so and shows the weight just below and the one just above, so you can pick the one that suits your workout. If you buy plates later, switch the new size on and the numbers update at once.
Warm-up sets
The table under the bar shows a warm-up ladder for your target weight. It starts with the empty bar for 10 easy reps, then adds about 40 % for 5, 60 % for 3 and 80 % for 2. For a heavy load it adds a single at 90 %. Each step is rounded down to the closest weight you can load with your plates, and steps that land on the same weight are dropped.
The idea is simple. Light early sets let you rehearse the movement and warm up the tissues you are about to load, and the falling number of reps keeps the warm-up from tiring you before your top set. Strength and conditioning textbooks describe the warm-up as a general part, followed by a specific part with the lift itself at lighter loads (Haff and Triplett 2016).
The exact percentages are a common pattern, not a law. Fewer steps are fine for a light day, an accessory lift or a weight you handle easily. Add a step if a joint is stiff or the jump to the top set feels big. Rest a minute or two between warm-up sets, and longer before your top set.
Plates in Muscla
The Muscla app has a plate calculator built in. You set which plates your gym has once. After that, every barbell set in your workout shows the plates per side, and the weights in your plan are rounded to what you can load. It uses the same logic as the calculator on this page. You never need a calculator at the rack: you read the plates and load them.
If you reached this page from the one-rep max calculator, the weight above is your estimated max. Most training uses a share of it, so change the number to the weight your program asks for.
Coming to the App Store. Free to start.
Questions
How much does an Olympic barbell weigh?
A men's Olympic barbell weighs 20 kg (45 lb). In weightlifting, the women's bar weighs 15 kg (35 lb); in powerlifting, women also lift with a 20 kg bar. Gym bars are usually close to this, but check the label or the end of the sleeve if your gym has older or special bars.
Do the collars count toward the weight?
Yes, if you use heavy ones. Competition collars weigh 2.5 kg each, so a pair adds 5 kg. Cheap spring clips weigh almost nothing and can be ignored. Choose Competition collars in the calculator when your gym uses them, or when you want the weight to match what you would lift at a meet.
Why does the calculator say my weight cannot be loaded?
Every plate goes on both sides, so the total always moves in steps of twice your smallest plate. With 1.25 kg plates the smallest step is 2.5 kg, so 101 kg does not exist: you can load 100 or 102.5. The calculator shows the closest weight below and the next one above, and you can tap either.
Which order do the plates go on?
Heaviest plates first, closest to the middle of the bar, then lighter ones toward the end, the same on both sides. A balanced bar is safer, and the collar sits snug against the lightest plate. The drawing shows this order for one sleeve.
Is a 45 lb plate the same as a 20 kg plate?
Nearly, but not exactly. A 45 lb plate weighs 20.4 kg, and a 20 kg plate weighs 44.1 lb. If you move between a gym with kilogram plates and one with pound plates, the difference adds up to a few percent on a heavy bar, so do not treat 100 kg and 225 lb as the same load.
How many warm-up sets do I need?
It depends on the weight and on how you feel. A common pattern is the empty bar for 10, then about 40, 60 and 80 % of your top weight for 5, 3 and 2 reps, and a single at 90 % when the load is heavy. Lighter days and lighter weights need fewer steps. The table is a starting point, not a rule.
Sources
- International Powerlifting Federation. Technical Rules Book, edition effective 1 March 2026. Rules on the barbell, collars and loading of the discs.
- International Weightlifting Federation. Technical and Competition Rules and Regulations 2025 (as of 5 November 2025). Bars of 20 kg (men) and 15 kg (women), collars of 2.5 kg each.
- National Institute of Standards and Technology. NIST Handbook 44, Appendix C: General Tables of Units of Measurement. 1 pound = 0.45359237 kg.
- Haff GG, Triplett NT, eds. Essentials of Strength Training and Conditioning. 4th ed. Champaign, IL: Human Kinetics; 2016. Chapter on warm-up: a general part followed by a specific part.