The bar on your Smith machine almost certainly doesn't weigh 20 kg — and if you've been treating it like it does, your training log has been wrong since session one.
The actual number comes down to three things: who made the machine, whether it's got a counterbalance system built in, and how old the equipment is. Most commercial bars at places like Anytime Fitness or Fitness First land somewhere between 6 and 11 kg once the counterbalance is factored in — a long way from the Olympic barbell standard.
Below, we break down every main machine type, show you how to nail down your exact bar weight in under two minutes, and explain why getting this right actually moves the needle on your progress.
What Is a Smith Machine?
A Smith machine is a barbell mounted to a guided rail system. The bar moves in a fixed path — straight up and down or on a slight incline, depending on the design — which means it stays controlled without you having to manage balance at the same time.
For home gym training, this is the main selling point. No spotter needed. No bar drifting at the bottom of a heavy squat. You can push closer to your limits without someone standing behind you.
The limitation is the flip side of the same coin: because the machine handles stability, your smaller stabiliser muscles aren't being trained the way they would be on a free bar. It's worth knowing that when you transition between the two — your Smith numbers won't transfer directly.
There's one more thing that sets it apart from a standard barbell, and it's the whole reason you're reading this: the bar weight. A 20 kg Olympic barbell and a Smith machine bar are not the same thing, and the gap between them is bigger than most people expect.
How Much Does a Smith Machine Bar Actually Weigh?
Somewhere between 3 and 20 kg, depending on the machine. That's not a cop-out — it genuinely is that variable. Most bars you'll come across at a standard commercial gym land somewhere in the 7–11 kg range, but two things shift that number considerably: whether the machine has a counterbalance system, and what the bar itself is made of.
A lot of Smith machines — especially in commercial gyms — have a counterbalance system built into the frame that offsets some of the bar's actual weight. A bar that physically weighs 9 kg might only feel like 5 kg because the counterbalance is taking 4 kg off the top. That's the "starting resistance" you'll sometimes see listed separately in spec sheets.
Machines without that system — typically the heavy-duty ones, or many home gym Smith machines — give you the bar's full weight from the word go. Nothing's being offset. What you grip is what you lift.
Smith Machine Bar Weight by Machine Type
These are starting points, not guarantees. The only number that actually matters is the one on your specific machine — which is worth tracking down before you start logging weights.
How to Find Your Smith Machine's Bar Weight
At a commercial gym, ask the staff — they've heard it before. For a home setup, the search takes a bit longer because nobody's there to ask and the documentation isn't always reliable.
Start on the manufacturer's product page. In the spec table, you'll often find two weight figures sitting next to each other: bar weight and starting resistance. They're different. Bar weight is the physical weight of the bar. Starting resistance is the load you actually feel at the start of a lift, after the counterbalance system has offset whatever it offsets. Log the starting resistance, not the bar weight. For the Major Fitness B52 Smith Machine, the Smith bar weighs 14.2 kg with no counterbalance, so there's no difference between the two.
If the manual's gone missing or the machine came second-hand without paperwork, grab a luggage scale. Hook it onto the unloaded bar, slowly lift until it clears the safety hooks, and read the number. Run through it a couple of times and average the readings — the first one can sit a little high. What you get is the true starting resistance, counterbalance and all, which is actually the most useful number for your training log.
Still drawing a blank? Drop a message to the manufacturer's support team with the model name. Most are pretty good about responding, and bar weight is one of those questions they've answered a hundred times before.
Here's a habit worth building: once you've tracked down the number, write it on a strip of tape and stick it to the machine frame. Thirty seconds now, zero hassle later. Add it to your training log alongside the gym or location name — if you ever shift the setup or train somewhere else, you'll have it ready to go.
Why the Bar Weight Actually Matters
Here's the situation that catches people out. You've been logging 60 kg on the Smith machine for weeks — numbers climbing, sessions feeling good. Then you load the same weight plates onto a free barbell, or you front up to a gym with a heavier bar, and the lift stops you cold. Same weight plates. Completely different weight. That's not a bad day. That's just the maths catching up.
The tracking problem compounds over time. Smith machine bar weights range from under 7 kg to close to 20 kg depending on the machine. If you're moving between setups and not adjusting for the difference, your training log is recording fiction. Some sessions you'll feel stronger than you should, others inexplicably flat — and none of it has anything to do with how you're actually progressing.
There's a safety angle worth flagging too, particularly on heavier compound movements. Underestimate the bar weight and you can end up loading more than you're ready for on a deadlift or shoulder press. It doesn't come up often, but when it does it's avoidable — and knowing your bar weight is all it takes.
None of this is complicated. It's one number, found once, written down. From that point on, your log reflects what you actually lifted — which is what a training log is for.
Smith Machine Bar vs Olympic Barbell
Weight is the first thing most people clock — a standard Olympic barbell sits at 20 kg before you load anything, while most Smith machine bars come in well under that. But the weight gap is almost secondary to how differently the two behave under load.
The fixed rail means you're not wrestling with the bar for balance — it just goes where you push it. That's the feature that makes Smith machine training genuinely practical for a home gym where you're lifting on your own. The Olympic bar is a different proposition: every rep demands something from your stabilisers, and over time that adds up. Whether that's a reason to use it or avoid it depends entirely on what you're trying to get out of your training.
Most well-kitted home gyms end up running both. The Smith machine takes care of the sessions where control and safety matter most; the Olympic bar handles the heavy compound work where free movement is the point. They're not competing — they're doing different jobs.
FAQs
1. Is the bar still 20kg on a Smith machine?
Not necessarily. Unlike a standard Olympic barbell, Smith machine bars vary widely by brand and gym. Most commercial gyms in Australia use bars that weigh 15–20 kg, but some lighter counterbalanced bars can be as low as 6–9 kg. Always check with your gym — don't assume it's 20 kg just because that's the Olympic standard.
2. How to tell if bar is 15 or 20 kg?
Chuck a look at the machine — there's usually a sticker on the frame somewhere. Can't find one? Just ask at the front desk, they'll sort you out. Beats guessing and logging dodgy numbers for weeks.
3. How much does a Smith machine bar weigh in kg?
Most commercial gym Smith machines run between 10 kg and 20 kg. Got a home setup? Could be anywhere from 7 kg depending on what you bought. The Major Fitness B52 Smith machine bar, for instance, comes in at 14.2 kg with no counterbalance. Worth finding out early so you're not cheating your own progress tracking.
4. Is 20 kg the same as 45 lbs?
Close, but not exactly. 20 kg = 44.09 lbs, while a standard US Olympic bar is 44.09 lbs (exactly 20 kg). The "45 lb bar" you see in American gym content is a slight rounding up — it's the same bar. So if you're following a US-based program and it says "45 lb bar," that's just your standard 20 kg bar.
5. Can you go heavier on a Smith machine?
Generally, yes. Because the bar runs on a fixed track, you don't have to worry about balancing it — which means a lot of people can push more weight than they would with a free barbell. Just keep in mind that what you lift on a Smith machine won't always translate directly to your barbell numbers.
Final Thoughts
If you're setting up a home gym around a Smith machine, this number matters more than it would at a commercial gym. At a public gym there's usually a label somewhere, or someone at the desk who knows. At home, neither of those options exist — and if you get the bar weight wrong from the start, every session you log is built on a figure that's off.
For the Major Fitness B52, the Smith machine bar weight is 14.2 kg. For every other machine: look it up, write it on a strip of tape, stick it to the frame. Thirty seconds of effort, and you won't have to think about it again.
One number. Found once. From that point on, your training log reflects what you actually did.
References
1. IWF — Equipment Specifications: International Weightlifting Federation official equipment page specifying that a men's Olympic barbell weighs 20 kg (44 lbs) — the global standard against which Smith machine bar weights are commonly compared.
2. PMC — Using Machines or Free Weights for Resistance Training in Novice Males? A Randomized Parallel Trial: 10-week randomised trial published in International Journal of Environmental Research and Public Health showing positive strength transfer in both directions between Smith machine and free-weight training, with free weights eliciting greater stabiliser recruitment at submaximal loads.
