Barbell plate calculator (plates per side)

A barbell plate calculator tells you which plates to put on each side of the bar to reach a target weight. The maths is simple: take away the bar (and collars, if you use them), halve what's left, and build that number from the heaviest plates down. For 100 kg on a 20 kg Olympic bar with no collars, that's 40 kg a side, or a 25, a 10 and a 5.

How the calculator works

1. Subtract the bar and collars. Target minus bar weight minus both collars.
2. Halve it. That's the weight per side, since both sides must match.
3. Load from heaviest to lightest. The calculator takes the biggest plate that fits, then the next, and so on, but only from the plates you ticked and only as many pairs as you said are free.
4. If the exact weight can't be made, it searches every combination your plates allow and shows the nearest total, plus the next option on the other side.

Say you want 101 kg on a 20 kg bar with no collars, and your gym's smallest plates are 2.5 kg. That's 40.5 kg a side, which 2.5 kg steps can't make. The nearest options are 40 kg a side (100 kg total) and 42.5 kg a side (105 kg total), and the calculator shows both. Add 1.25 kg plates and you could make 102.5 kg; add 0.5 kg plates and 101 kg works exactly. Small fractional plates are often missing in commercial gyms, which is why the plate list lets you untick them.

What does an Olympic barbell weigh?

The two big federations publish exact specs:

The weightlifting numbers come from the IWF Technical and Competition Rules & Regulations and the powerlifting numbers from the IPF Technical Rulebook (2026). So in competition the bar and collars together are 25 kg for men and 20 kg for women in weightlifting, and 25 kg in powerlifting.

Most gym-goers don't use competition collars. Spring clips are light enough to ignore, so pick "None / spring clips" unless you really use the 2.5 kg locking kind.

Why you should weigh your gym's bar

Many Indian commercial gyms have a mix of bars: a full-size Olympic bar, shorter straight bars, EZ curl bars and fixed-weight bars. Only competition-grade bars are made to a published spec. The shorter bars especially vary a lot from one maker to the next, and the number painted on them (if there is one) isn't always the real weight.

Plates are the same story. The IPF requires competition discs to be within 0.25% or 10 grams of their face value. Ordinary cast-iron gym plates aren't held to that tolerance, and old ones chip and rust. The only way to know what a plate really weighs is to put it on a scale.

None of that matters much for day-to-day training, as long as you use the same bar and plates each week. It matters when you compare numbers between gyms, or when you're chasing a specific total. The fix takes two minutes: put the bar on a weighing scale (a luggage scale or the gym's body-weight scale works), then use the Custom: weigh your bar option. That's why the 10 kg and 7 kg straight-bar options here are labelled "weigh your bar": they're common sizes, not a standard.

What do the plate colours mean?

Competition plates are colour-coded so referees can read the weight from a distance. The calculator draws them in the IWF colours:

The IWF also has 2 kg blue, 1.5 kg yellow and 1 kg green change plates. The IPF lets plates of 10 kg and under be any colour, so you'll see different schemes on powerlifting plates. In the drawing, 1.25 kg is shown in chrome. Pound plates have no colour standard, so lb mode draws them grey.

Both federations also say the heaviest plates go on first, with lighter ones outside them. Do the same in the gym: it keeps the load close to your hands and makes the weight easy to check.

How to use the warm-up ramp

The table under the calculator gives one common way to build up to a heavy set: the empty bar for 10 reps, then about 40%, 60%, 80% and 90% of your working weight for 5, 3, 2 and 1 reps. It's one approach, not a rule. Lighter working sets need fewer steps, and the table drops any step that would round down to the empty bar or repeat the previous load. Every load is rounded to the nearest 5 kg (10 lb in pound mode) and then to something your ticked plates can actually make.

If your programme gives weights as percentages of your max, find that max first with the one-rep max calculator. The 1RM percentage chart guide explains which percentages suit strength or muscle, and the push pull legs split shows where heavy barbell work fits in a training week.

Limits

• The totals are only as accurate as your bar and plates. With uncalibrated gym equipment, treat every number as approximate.
• Pound mode treats 45 lb and 35 lb as the bar weights because that's how those bars are usually labelled. A 20 kg bar is really 44.1 lb.
• Make sure the bar has room. Long stacks of thin plates may not fit on a short straight bar.
• Use safety bars or a spotter for heavy squats and bench presses.

Useful links

• IWF Technical and Competition Rules & Regulations, 2020 edition (bar, disc and collar specs)
• IPF Technical Rulebook 2026 (bars, discs, collars)
• IPF technical rules page