Every weight you calculate starts from the bar, so if you don’t know what the bar weighs, every number after it is wrong. Most lifters assume “the bar is 45” and leave it there. That’s right about half the time. The other half, you’re loading a 20 kg bar, or a 15 kg women’s bar, or a Smith machine that could weigh almost anything. Here’s the full reference, so you never have to guess the starting number again.
The two you’ll meet most
- Men’s Olympic bar: 20 kg (about 44 lb). The standard bar in most serious gyms worldwide, and every kilo gym. It’s the one people call “45” even though it’s actually 44.
- US pound bar: 45 lb (about 20.4 kg). The standard American iron bar. Genuinely 45 lb, a hair heavier than the 20 kg bar.
That 1 lb gap between “the 45” and “the 20 kg” seems trivial, but it’s the reason a bar you thought was empty at 45 keeps every pound number in an all-kilo gym slightly off. If you learned to lift in pounds and now train where the plates are in kilos, that mismatch is the whole story.
The full reference table
| Bar | Weight (kg) | Weight (lb) | Notes |
|---|---|---|---|
| Men’s Olympic | 20 kg | ≈ 44 lb | The default in kilo gyms |
| US pound bar | ≈ 20.4 kg | 45 lb | The default in US gyms |
| Women’s Olympic | 15 kg | ≈ 33 lb | Thinner shaft (25 mm), shorter |
| Training / technique bar | 5–10 kg | ≈ 11–22 lb | For learning the lifts light |
| Deadlift bar | 20 kg | ≈ 44 lb | Longer, thinner, whippier, same weight |
| EZ curl bar | ≈ 7–12 kg | ≈ 15–25 lb | Varies a lot by brand |
| Trap / hex bar | ≈ 20–32 kg | ≈ 45–70 lb | Wide range, check the model |
| Safety squat bar | ≈ 25–32 kg | ≈ 55–70 lb | The pad and yoke add weight |
| Smith machine bar | 0–15 kg | 0–30+ lb | See below. This is the tricky one |
The top four are dependable. The bottom five vary by manufacturer, so treat those numbers as a starting range and confirm the specific bar when it matters.
The bar that lies to you: the Smith machine
The Smith machine is the single biggest source of “wait, what am I actually lifting?” confusion, and it’s worth its own section.
The bar rides on rails, and many machines are counterbalanced, meaning a hidden weight offsets the bar so the effective load you feel is far less than a free bar, sometimes as little as 6–15 lb, sometimes essentially zero. Non-counterbalanced machines run heavier, around 15–30 lb. The angle of the rails changes things too.
The practical upshot: you cannot compare Smith machine numbers to free-bar numbers, and you can’t even compare one gym’s Smith machine to another’s. If a number matters to you on the Smith, load it, unrack it by feel, and treat that machine as its own private measuring system.
Why this matters more than 1 lb
You might think a few pounds of bar difference is noise. Two places it isn’t:
- Warm-ups and empty-bar work. When you start a session on “just the bar,” the difference between 45 lb and 44 lb (or a 33 lb women’s bar) is a real percentage of the load. Start from the right number.
- Progressive overload over months. If you log “empty bar” as 45 in a gym where it’s really 20 kg, every entry inherits that error. Your log should match the bar in front of you, not the bar you grew up with.
Set your bar weight once and every total falls out of it: bar + 2 × (one side). If you want that math done for you, MixedBarbell lets you tell it which bar you’re on, then hands you the plates for any target from there.
Try it with the real numbers
The empty 20 kg bar is a page of its own: see the 20 kg bar. From there, add plates and watch the total: 60 kg, 100 kg, 225 lb, 315 lb. Every one of them starts from the bar.
Related: how to read any loaded barbell · standard plate weights, kg vs lb