Barbell & plate guide
Plate colors, sizes and weights, plus barbell and collar dimensions, the reference behind the calculator. Numbers follow the IWF weightlifting standard; individual brands vary slightly.
Plate color codes
Competition kg plates follow a fixed color code, so an experienced eye reads the load at a glance. The plates below are drawn to the standard – embossed, naturally, with the only brand that matters here.
- 25 kg · Red
- 20 kg · Blue
- 15 kg · Yellow
- 10 kg · Green
- 5 kg · White
Below 10 kg, weights are usually smaller steel “change plates” rather than full-diameter bumpers: 5 kg white, 2.5 kg red, 1.25 kg chrome, and fractional plates (also called micro plates) down to 0.25 kg for micro-loading.
Bumper vs iron plates
Bumper plates are rubber-coated and built to be dropped – Olympic lifters and CrossFitters bounce them off the platform, which also lets you pull deadlifts from a consistent height and spares the floor. Competition bumpers share the 450 mm diameter at every weight and follow the kg color code. Iron plates are thinner and cheaper per kg, so they're typical for the small “change” sizes and for lifts you rack rather than drop (squat, bench, press). Plenty of home and garage gyms mix the two: bumpers for the big lifts, iron for the change plates.
For jumps smaller than the lightest plate, fractional plates (a.k.a. micro plates) go down to 0.25 kg / 0.25 lb, so you can micro-load a stalling lift. The calculator uses them automatically when they get you an exact total.
Plate dimensions
Full-size competition discs all share a 450 mm diameter and a 50 mm center hole; only the thickness changes with weight.
| Plate | Color | Diameter | Thickness |
|---|---|---|---|
| 25 kg | Red | 450 mm | ≈ 67 mm |
| 20 kg | Blue | 450 mm | ≈ 54 mm |
| 15 kg | Yellow | 450 mm | ≈ 43 mm |
| 10 kg | Green | 450 mm | ≈ 35 mm |
Barbell dimensions
The two standard Olympic bars. The women's bar is shorter and lighter with a thinner 25 mm shaft, easier to grip for smaller hands. A US “45 lb” bar is essentially the 20 kg bar (20 kg ≈ 44 lb).
| Spec | Men's bar | Women's bar |
|---|---|---|
| Weight | 20 kg (≈ 44 lb) | 15 kg (≈ 33 lb) |
| Total length | 2200 mm | 2010 mm |
| Shaft / grip diameter | 28 mm | 25 mm |
| Sleeve diameter | 50 mm | 50 mm |
| Loadable sleeve length | ≈ 415 mm | ≈ 320 mm |
| Distance between sleeves | ≈ 1310 mm | ≈ 1310 mm |
Collars
Collars lock the plates on. Competition collars are a real weight; spring clips are negligible. The calculator counts plates only, so add collar weight yourself if it matters for your total.
| Type | Weight (each) | Per pair |
|---|---|---|
| Competition collar | 2.5 kg | 5 kg |
| Spring clip | ≈ 0.25 kg | ≈ 0.5 kg |
| Lock-jaw / plastic | ≈ 0.2–0.5 kg | ≈ 0.4–1 kg |
Barbell trivia
Why the men's bar has a center knurl
Look closely at a 20 kg men's bar and there's a rough patch of knurling dead center – the women's 15 kg bar has none. It's a historical leftover: early Olympic weightlifting included one-arm lifts, and the center knurl gave grip for single-arm work. The one-arm snatch was dropped in 1924, but the men's bar never changed. The women's bar, introduced for the 2000 Sydney Games, was simply designed without it.
Shaft diameter and "whip"
Not all 20 kg bars are equal. An Olympic weightlifting bar uses a 28 mm shaft that flexes – the "whip" lets lifters store and release energy in explosive lifts like the clean & jerk. A powerlifting bar runs 29 mm or thicker to stay stiff under heavy static squats and benches. The women's bar drops to 25 mm for smaller hands.
The first modern barbell
Before the 1900s, strongmen used thick, fixed-sleeve bars. The rotating sleeve, which spins so plates don't torque your wrists, was pioneered in Germany: Franz Veltum and Kaspar Berg built early revolving barbells around 1905–1910, and the "Berg Barbell" became the global standard after the 1928 Amsterdam Olympics.
Why competition plates share one diameter
Competition bumpers are all 450 mm across so the bar always sits at the same height off the floor, only the thickness changes with weight. The strict color code does the rest: experienced loaders read the bar by its color pattern, not a calculator.
The math
Loading is symmetric: per-side weight = (target − bar) ÷ 2, mirrored on both ends. See how many plates that is for the milestone chart, or let the calculator do it for any weight and any plate set.
FAQ
- What do the barbell plate colors mean?
- They're the IWF weightlifting standard: 25 kg red, 20 kg blue, 15 kg yellow, 10 kg green, 5 kg white. It lets you read the load by color from across the gym. Pound plates aren't standardized the same way, though many follow a similar scheme.
- How thick is a barbell plate?
- Full-size 450 mm competition bumpers get thicker with weight, roughly 35 mm for a 10 kg up to about 67 mm for a 25 kg. Thickness matters because it sets how many plates fit on the sleeve.
- What's the difference between bumper plates and iron plates?
- Bumper plates are rubber-coated and made to be dropped, so they suit Olympic lifts and CrossFit and let you deadlift from a consistent height while protecting the floor. Competition bumpers all share the 450 mm diameter and follow the kg color code. Iron plates are thinner and cheaper, common for the small change sizes and for lifts you rack rather than drop. Fractional plates, also called micro plates, go down to 0.25 kg or 0.25 lb for micro-loading.
- How long is an Olympic barbell?
- A men's 20 kg bar is 2200 mm long with a 28 mm shaft; a women's 15 kg bar is 2010 mm with a thinner 25 mm shaft. Both use 50 mm sleeves that fit Olympic plates.
- Do collars add to the weight?
- Yes. Competition collars are 2.5 kg each (5 kg per pair); spring clips are about 0.25 kg each. Plates Calc computes the plates only – add collar weight on top if you use heavy ones.
- Why does the men's barbell have a center knurl?
- It's a historical leftover from early Olympic one-arm lifts, which needed a center grip. The one-arm snatch was dropped in 1924 but the men's 20 kg bar kept the center knurl. The women's 15 kg bar, introduced in 2000, was designed without it.
- What is barbell whip?
- Whip is the flex of the shaft. Olympic weightlifting bars use a 28 mm shaft that flexes to store and release energy in explosive lifts; powerlifting bars are 29 mm or thicker to stay stiff under heavy static loads.