Barbell Plate Calculator: Plates per Side, kg and lb (Free)
Enter the weight you want on the bar and see which plates go on each side, with the closest loadable total when your target does not split cleanly.
Plates per side
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Quick answer
To load a barbell, subtract the bar weight from your target, halve the remainder, and build that half on each side with the largest plates first. For 100 kg on a 20 kg bar that is 40 kg per side: one 25 and one 15. For 225 lb on a 45 lb bar it is 90 lb per side: two 45s. The calculator above does the subtraction, the halving and the plate choice for you, and tells you the nearest weight you can actually load when the target does not divide evenly.
This calculator runs entirely in your browser: nothing you type is uploaded, stored or tied to an account. You give it a target weight, tell it which bar you are using, and it tells you which plates to put on each side, drawn as a small diagram so you can check it against the bar in front of you.
Loading a bar is not hard arithmetic, but it is arithmetic done between sets, with a resting heart rate of 140 and a rack of mixed plates in front of you. Most loading mistakes are not about maths ability; they are about doing the maths while thinking about something else. The calculator takes that job away so you can think about the lift.
How to use it
- Type your target weight. This is the total you want on the bar, including the bar itself. If your program says 100 kg, type 100.
- Pick your bar. The drop-down lists 20 kg, 15 kg and 10 kg bars, plus 45 lb and 35 lb. A standard men's Olympic bar is 20 kg or 45 lb; a women's bar is 15 kg or 35 lb; the 10 kg option covers technique bars.
- Pick your unit. Kilograms or pounds. Match this to the plates in your gym, not to the unit in your head.
- Read the result. The big number shows the plates for one side, largest to smallest, for example
25 + 15 kg. Load the same on the other side. - Check the note underneath. It says either "Loads exactly" with your total, or "Closest loadable weight" with the nearest total the plate set can actually reach.
The diagram under the result draws the bar and the plates in order, heaviest nearest the collar. If the diagram does not match what is on your bar, one of you is wrong, and it is usually worth checking which.
How the maths works
There are three steps, and the calculator does them in this order.
Subtract the bar. The bar is part of the total but it is not a plate, so it comes off first. Target 100 kg on a 20 kg bar leaves 80 kg of plates to find.
Halve it. Plates go on both ends, so each side carries half. 80 kg becomes 40 kg per side. This is the number that matters at the rack, and it is the one people most often forget to halve, which is how a 100 kg squat becomes a 180 kg squat for one surprising second.
Load greedily, largest plate first. The calculator walks down the plate set from heaviest to lightest and, at each size, adds as many of that plate as still fit in what remains. For 40 kg per side: one 25 leaves 15; a 20 does not fit; one 15 leaves 0. Result: 25 + 15. For 90 lb per side: two 45s and done. For 42.5 kg: 25 + 15 + 2.5.
This is the same method most experienced lifters use without naming it, and it has a useful property. Because every plate in the standard set is a whole multiple of the smallest one (1.25 kg or 2.5 lb), the greedy walk always finds the combination with the fewest plates. Fewer plates means less sleeve used, less flex, and less to take off between sets.
Why some targets are not loadable. The smallest plate sets the resolution. With 1.25 kg plates, each side can only change in 1.25 kg steps, so the total on the bar can only change in 2.5 kg steps. Ask for 101 kg and there is no combination that produces it; the closest is 100 kg or 102.5 kg. The calculator reports the closest total it can reach without going over, and labels it "Closest loadable weight" so you know the number you typed was not the number you will lift. In pounds the smallest standard plate is 2.5 lb, so totals move in 5 lb steps and a request for 227 lb resolves to 225 lb.
The same logic explains the message when your target is below the bar weight. There is nothing to subtract from, so the calculator tells you so rather than showing negative plates.
Two edge cases worth knowing. First, a target equal to the bar weight returns "Empty bar", which is correct and sometimes the right answer for a warm-up. Second, the calculator assumes you have as many of each plate as you need. If your rack has a single pair of 25s and someone else is using them, load two 10s and a 5 instead; the total is the same, the sleeve is a little more crowded.
Standard plates and bars
Competition plates are colour-coded so that a loader, a referee or a lifter across the room can read the bar at a glance. Both the powerlifting and weightlifting federations use the same colours for the large plates, and most gym plate sets, whether rubber bumpers or cast iron, have adopted them.
| Colour | Weight (kg) | Common lb equivalent |
|---|---|---|
| Red | 25 kg | 55 lb (or a 45 lb plate, often blue or black) |
| Blue | 20 kg | 45 lb |
| Yellow | 15 kg | 35 lb |
| Green | 10 kg | 25 lb |
| White | 5 kg | 10 lb |
| Change plates | 2.5 kg (red), 2 kg (blue), 1.5 kg (yellow), 1 kg (green), 0.5 kg (white) | 5 lb, 2.5 lb, plus fractional plates |
The kilogram and pound sets are not conversions of each other. A 20 kg plate is 44.1 lb, a 45 lb plate is 20.4 kg. Gyms that mix the two, and many do, end up with bars that are a few hundred grams off what the numbers say. That does not matter for training, but it is why the calculator makes you pick one unit and stay in it.
Bars are simpler.
| Bar | Weight | Typical use |
|---|---|---|
| Men's Olympic bar | 20 kg / 45 lb | Squat, bench, deadlift, most of the rack |
| Women's Olympic bar | 15 kg / 35 lb | Thinner shaft, shorter, common in weightlifting and many commercial gyms |
| Technique bar | 10 kg or lighter | Learning the lifts, warm-ups, rehab |
There is a full run-down of every bar you are likely to meet, including EZ, trap and safety squat bars, in how much does a barbell weigh. The short version: if a bar is unmarked and looks standard, treat it as 20 kg or 45 lb, and if it has a curve, a hex or a yoke on it, look for a stamp before you trust any number.
Loading etiquette and safety
None of this is complicated, and all of it gets skipped on a busy Monday.
- Use collars. A plate that walks off one end during a set unloads that side instantly, and the bar swings. On squats and presses this is the mechanism of most serious barbell accidents. Spring collars take two seconds.
- Load symmetrically, in the same order. Both sides should carry the same plates in the same sequence, heaviest against the collar. An asymmetric bar loads one side of your body more than the other and is easy to miss on a bar that looks full.
- Plates facing in. On most plates the flat side faces the collar and the lip faces out, so the plates seat flush against each other and the collar seats flush against the outer plate. Some bumpers are symmetric and it does not matter; when it does, the plates tell you.
- Alternate sides when loading heavy. Put one 25 on the left, then one on the right, then the next pair. Loading three plates on one side before touching the other tips the bar off the rack hooks.
- Strip the bar the same way, one side at a time in small steps. A bar with 60 kg on one end and nothing on the other will flip.
- Put plates back where they came from. The plate you cannot find is usually on someone else's bar because they could not find it either.
Plate slang: what "two plates" means
Lifters count plates on one side of the bar, and they count only the biggest plate in the set. "A plate" is one big plate per side; "two plates" is two per side.
In a kilogram gym the big plate is 20 kg, so one plate is 60 kg total (20 + 20 + the 20 kg bar), two plates is 100 kg, three is 140 kg, four is 180 kg. In a pound gym the big plate is 45 lb, so one plate is 135 lb, two plates is 225 lb, three is 315 lb, four is 405 lb.
The two systems do not line up. A metric two plates is 100 kg, which is about 220 lb; an American two plates is 225 lb, which is about 102 kg. Close enough to nod along in conversation, not close enough to log. The full breakdown, with a table, is in what does two plates mean.
This matters for logging as much as for talking. If you dictate your sets, the parser has to know which gym you are in. Strongbro's voice logging does: say "bench, two plates for five" and it writes 100 kg on a metric setting or 225 lb on an imperial one, and "forty a side" becomes 100 kg with the bar added, so the number in your log is the number that was on the bar.
The other tools
The plate calculator answers "what do I put on the bar". The other two free tools answer the questions on either side of it.
- One-rep max calculator — turn any hard set into an estimated max and the percentages a program asks for. Work out that 85 percent of your estimated max is 102.5 kg, then come back here to load it.
- Training volume calculator — weight times reps, summed across sets, so you can compare this week's work with last week's.
All three run in the browser, store nothing, and need no account.
Where to go next
Loading the bar correctly is the first step; the second is knowing what to load next week. How to apply progressive overload covers the loop: repeat a weight until you own every prescribed rep, then add the smallest plate you have. That guide is also why fractional plates are worth the money on pressing movements.
If you log in Strongbro, the workout keypad prefills last session's weight so the plate maths for the next set is usually "same as before, plus 2.5". And if you prefer not to type mid-set at all, voice logging takes the sentence you would say to a training partner and turns it into structured sets, plate slang included. Either way, the log ends up with the real total on the bar, which is what your progress tracking depends on.
The bottom line
Subtract the bar, halve the rest, load the biggest plate that fits and repeat. The calculator on this page does exactly that with the standard kilogram and pound plate sets, tells you when a target cannot be loaded and what the nearest one is, and draws the result so you can check it at the rack. Use collars, load both sides the same way, and remember that "two plates" means 100 kg in one gym and 225 lb in another.
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Frequently asked questions
Does the plate calculator include the bar weight?
Yes. The target you type is the total on the bar, bar included. The calculator subtracts the bar you select (20, 15 or 10 kg, or 45 or 35 lb), halves what is left, and shows plates for one side. If you want to know the plates for a per-side figure instead, double it, add the bar, and enter that total.
Why does it say my target is not loadable?
Because the half-per-side remainder cannot be built from the plate set. With a 20 kg bar and 1.25 kg as the smallest plate, totals move in 2.5 kg steps, so 101 kg is impossible and the calculator shows 100 kg as the closest loadable weight. In pounds the smallest plate is 2.5 lb, so totals move in 5 lb steps.
Which plates does the calculator assume I have?
The standard competition set. In kilograms: 25, 20, 15, 10, 5, 2.5 and 1.25. In pounds: 45, 35, 25, 10, 5 and 2.5. It assumes an unlimited number of each, which matches most commercial gyms. If your rack lacks a size, load the equivalent from smaller plates, for example two 10s in place of a missing 20.
What does 'plates per side' mean?
The list of plates that goes on one sleeve of the bar. You load the same list on the other sleeve. A result of 25 + 15 means one 25 kg plate and one 15 kg plate on the left, and the same pair on the right, for a total of 80 kg of plates plus the bar.
Can I use it for a 15 kg women's bar or a 35 lb bar?
Yes. Pick the bar from the drop-down before reading the result. The 15 kg bar changes every per-side figure by 2.5 kg compared with a 20 kg bar, which is why a set that felt right on one bar can feel off on the other. The 10 kg option covers technique bars and lighter training bars.
Does it handle mixed kg and lb plates?
No. Choose one unit and the calculator uses that unit's plate set and expects the bar to match. Mixing a 45 lb bar with kilogram plates is common in gyms that were fitted out in stages, so if that is your situation, convert the bar to 20.4 kg mentally and accept that the total will be off by a few hundred grams.
Why do the plates load largest first?
Two reasons. Heavy plates sit closest to the collar where the sleeve is stiffest, which keeps the bar balanced and the load from whipping. And the greedy method, taking the largest plate that still fits, always produces the fewest plates for a given weight when plate sizes are multiples of the smallest, which they are in both standard sets.
How do I load a weight that needs a 0.5 kg or 1 lb change?
You need fractional plates, sometimes called micro plates, that this calculator does not include. They come in 0.25, 0.5 and 1 kg, or 0.25, 0.5, 1 and 1.25 lb. They are the practical way to add weight to pressing movements weekly rather than jumping 2.5 kg at a time, and they fit in a gym bag.
Does the calculator send my numbers anywhere?
No. The whole thing is a few lines of JavaScript that run in your browser. Nothing is uploaded, nothing is stored, and there is no account. Reload the page and it starts from 100 kg on a 20 kg bar again.
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