Barbell Plate Loading Math: How to Hit Any Target Weight in kg and lb
October 21, 2026
Loading a barbell is simple arithmetic once you know the bar's weight: target weight minus bar weight, divided by two, gives the weight to put on each side. A standard Olympic men's barbell weighs 20 kg (44.1 lb, usually treated as 45 lb in US gyms), and a women's bar weighs 15 kg (33 lb). For a 100 kg lift on a 20 kg bar: (100 − 20) ÷ 2 = 40 kg per side, which can be a 20 kg and a 20 kg plate, or a 25 and a 15.
In pound-based gyms, a target of 225 pounds on a 45-pound bar needs (225 − 45) ÷ 2 = 90 pounds per side, which is two 45-pound plates. Knowing the plate sizes in your gym and the standard combinations makes setup quick and avoids mistakes.
Skip the math and get your answer instantly:
Open the One-Rep Max Calculator →Standard Plate Sizes
Metric gyms use plates of 25, 20, 15, 10, 5, 2.5, and 1.25 kg. US gyms use 45, 35, 25, 10, 5, and 2.5 lb, and sometimes 55 lb or 100 lb plates. Competition plates are color-coded in kilograms: red 25, blue 20, yellow 15, green 10, white 5. Fractional plates down to 0.25 kg or 0.5 lb enable small increases.
| Target (kg) | Bar | Per side | Plates per side |
|---|---|---|---|
| 60 | 20 kg | 20 kg | 20 |
| 80 | 20 kg | 30 kg | 20 + 10 |
| 100 | 20 kg | 40 kg | 25 + 15 |
| 120 | 20 kg | 50 kg | 25 + 25 |
| 140 | 20 kg | 60 kg | 25 + 25 + 10 |
| 182.5 | 20 kg | 81.25 kg | 25 x 3 + 5 + 1.25 |
Pound Loading Examples
With a 45-pound bar: 135 pounds is one 45 per side. 185 is a 45 and a 25. 225 is two 45s. 275 is two 45s and a 25, since (275 − 45) ÷ 2 = 115 per side. 315 is three 45s per side, since (315 − 45) ÷ 2 = 135. 405 is four 45s per side, since (405 − 45) ÷ 2 = 180.
These round numbers have names among lifters: one plate (135), two plates (225), three plates (315), and four plates (405).
Converting Between kg and lb
1 kg = 2.20462 lb, and 1 lb = 0.453592 kg. A 100 kg barbell is 220.5 lb, while 225 lb is 102.1 kg, so a 225 lb lift is a little more than 100 kg. A 135 lb loaded bar is 61.2 kg. A 45 lb bar (20.4 kg) is about the same as a 20 kg bar, within 2%, so US lifters can treat them as equivalent when comparing, but should be careful for competition records.
When following a program written in kilograms in a pound gym, round loads to the nearest 5 lb increment, or use fractional plates, and remember that the bar's weight is part of the total.
Microloading for Steady Progress
Adding 5 kg to a lift each week is impossible for long, particularly for upper-body lifts. Small plates (1.25 kg or 0.5 kg) allow increases of 0.5 to 2.5 kg total. An increase of 2.5 kg on a 100 kg lift is 2.5%, which is a significant jump for the bench press. Microloading helps you progress consistently for months longer than jumping by 5 kg.
Remember that collars add about 2.5 kg for competition clamps and ignore them for casual training unless you need accuracy.
Safety Notes
Load plates evenly on both sides so that the bar remains balanced, use collars for lifts where plates may slide, and pay attention to bar ratings: some bars are rated for a maximum load, usually well above recreational lifts. Keep the heavier plates closest to the center unless the gym's convention is otherwise, and strip the bar evenly after a set.
Frequently Asked Questions
How do I calculate plates per side?
Subtract the bar weight from the target, then divide by two.
How much does an Olympic barbell weigh?
20 kg (about 45 lb) for the men's bar and 15 kg (33 lb) for the women's bar.
How many plates is 225 pounds?
Two 45-pound plates per side on a 45-pound bar.
How many kilograms is 225 lb?
About 102 kg.
What are microplates?
Small plates, usually 0.25 to 1.25 kg, used to make tiny increases in weight.