Key Takeaways
- Always subtract the bar weight first, then divide by 2 for weight per side
- Standard Olympic barbells weigh 45 lbs (20 kg)
- Load plates from heaviest to lightest (closest to center)
- Use collars to secure plates - safety first
- Common plate weights: 45, 35, 25, 10, 5, 2.5 lbs
How to Calculate Plate Weight
Calculating which plates to load on a barbell is straightforward once you understand the basic formula. The key is remembering that you load the same weight on each side of the bar.
The Basic Formula
Weight Per Side = (Target Weight - Bar Weight) / 2
For example, if you want 225 lbs total with a 45 lb bar:
- 225 - 45 = 180 lbs (weight needed from plates)
- 180 / 2 = 90 lbs per side
- Load: Two 45 lb plates on each side (2 x 45 = 90)
Standard Weight Plate Sizes
| Plate (lbs) | Plate (kg) | Color Code | Common Use |
|---|---|---|---|
| 45 lbs | 20 kg | Blue or Red | Primary loading plate |
| 35 lbs | 15 kg | Yellow | Mid-range adjustments |
| 25 lbs | 10 kg | Green | Common increment |
| 10 lbs | 5 kg | White | Fine adjustments |
| 5 lbs | 2.5 kg | White | Small increments |
| 2.5 lbs | 1.25 kg | White | Microloading |
Common Barbell Weights
- Men's Olympic Bar: 45 lbs (20 kg), 7.2 feet long
- Women's Olympic Bar: 35 lbs (15 kg), 6.5 feet long
- Standard Bar: 15-25 lbs, varies by manufacturer
- EZ Curl Bar: 15-25 lbs, designed for arm exercises
- Trap/Hex Bar: 45-65 lbs, for deadlifts and shrugs
Loading Tips for Safety
- Load evenly: Always add the same weight to both sides
- Use collars: Secure plates with barbell collars
- Heavy to light: Place heavier plates closer to the center
- Check the rack: Make sure the bar is secure before loading
- Have a spotter: For heavy lifts, always use a spotter or safety bars
Frequently Asked Questions
A standard men's Olympic barbell weighs 45 lbs (20 kg) and is 7.2 feet long. The women's Olympic bar weighs 35 lbs (15 kg) and is 6.5 feet long with a thinner grip diameter.
With a 45 lb bar, 135 lbs requires one 45 lb plate on each side. (45 + 45 + 45 = 135 lbs). This is considered a "plate" in gym terminology and is a common milestone for beginners.
To convert lbs to kg, divide by 2.205. To convert kg to lbs, multiply by 2.205. For example, 100 kg = 220.5 lbs, and 225 lbs = 102 kg (approximately).
Plate availability limits exact weights. With standard plates (45, 35, 25, 10, 5, 2.5 lbs), the smallest increment is 5 lbs (2.5 per side). For smaller jumps, consider purchasing fractional plates (1.25, 0.5 lbs).
Yes! When recording your lifts (bench press, squat, deadlift, etc.), always include the bar weight. A bench press with two 45 lb plates per side is a 225 lb bench, not 180 lbs.