A StairMaster generally burns more calories than a treadmill when both are used at moderate intensity, with estimates ranging from 600 to over 1,000 calories per hour on a StairMaster compared to 450 to 750 calories per hour on a treadmill at a flat or low incline. But that gap narrows quickly, and can even reverse, once you start adjusting speed and incline on the treadmill. The real answer depends on how hard you’re willing to work on each machine.
Calorie Burn at Moderate Effort
At a steady, moderate pace, the StairMaster has a built-in advantage: you’re lifting your body weight against gravity with every step. That constant vertical effort demands more energy than walking or light jogging on a flat treadmill. For a person weighing around 155 pounds, a moderate StairMaster session burns roughly 600 calories per hour, while walking briskly on a flat treadmill lands closer to 450.
The reason is simple mechanics. On a StairMaster, your muscles never get a “coasting” phase. Each step requires you to push your full body weight upward. On a flat treadmill, momentum carries you forward between strides, and your legs share the workload with gravity rather than fighting it the entire time.
How Treadmill Incline Changes the Math
A flat treadmill and an inclined treadmill are essentially two different machines when it comes to calorie burn. Walking on a 5% incline increases calorie expenditure by about 52% compared to flat walking. At 10% incline, that number jumps to 113%, more than doubling what you’d burn on a level surface.
This means a treadmill set to a steep incline can match or exceed the calorie burn of a StairMaster. Walking at 3.5 mph on a 10% to 12% incline pushes energy expenditure into the 700 to 900 calorie-per-hour range for most people, putting it squarely in StairMaster territory. And running on an incline pushes it even higher. So when people say “the treadmill burns fewer calories,” they’re usually picturing someone walking on a flat belt, which isn’t the only option.
Which Muscles Each Machine Works
The two machines target overlapping but meaningfully different muscle groups. Research measuring electrical activity in leg muscles during exercise found that the stepper activates the quadriceps (the front of your thigh) slightly more than the treadmill at every intensity level. At high effort, quad activation on the stepper was about 10 to 15% greater than on the treadmill.
The treadmill, on the other hand, dominated in hamstring and glute activation. Hamstring activity on the treadmill was roughly 40 to 60% higher than on the stepper across all intensity levels. Glute activation followed a similar pattern, with the treadmill producing about 40% more activity than the stepper. This makes sense: running and walking involve a powerful hip extension and a “pulling” motion through your hamstrings that stair climbing doesn’t replicate as strongly.
If your goal is building stronger glutes and hamstrings alongside your cardio, the treadmill (especially at an incline) gives those muscles more work. If you want to emphasize your quads and calves, the StairMaster is the better choice.
Why the StairMaster Feels Harder
Most people report that the StairMaster feels significantly more difficult than the treadmill, even when the two machines produce similar heart rates. One reason is that there’s no rest phase in stair climbing. On a treadmill, each stride has a brief moment where your leg swings forward passively. On the StairMaster, you’re actively pushing down with one leg while lifting the other, creating a continuous demand on your muscles.
Research from Eastern Illinois University highlighted another factor: how much you lean on the handrails. Subjects who supported their upper body on the StairMaster rated the workout about 12 out of 20 on the perceived exertion scale (a “somewhat hard” effort). Those who let go of the rails rated the same session at 14 out of 20 (“hard”), and described the workout as feeling like it “lasted forever.” That’s a meaningful jump in difficulty from a single change in hand position. If you’re gripping the rails and leaning your weight onto them, you’re reducing calorie burn substantially and making the machine less effective than the numbers suggest.
Choosing Based on Your Goals
For pure calorie burn in the shortest time, the StairMaster is more efficient at a default moderate pace. You don’t have to think about settings. Just step on, pick a level, and the machine forces a high calorie output. For someone who wants a time-efficient fat-burning session and doesn’t enjoy running, it’s a strong choice.
The treadmill offers more range. At low settings, it’s a gentle recovery tool. At high incline and moderate speed, it matches the StairMaster’s calorie burn while loading your glutes and hamstrings more heavily. And at a full run, it can surpass the StairMaster entirely, with experienced runners burning 800 to over 1,000 calories per hour depending on pace and body weight. That versatility makes the treadmill better suited if you want to vary your workouts or train for running-specific goals.
Joint Impact and Sustainability
The StairMaster is a low-impact machine. Your feet never leave the pedals, so there’s no jarring landing force on your knees, hips, or ankles. This makes it a practical option for people with joint pain, shin splints, or stress fracture history who still want a high-calorie workout.
Treadmill walking is also low-impact, but running introduces repetitive ground-reaction forces of two to three times your body weight with each stride. Over time, that adds up. If you’re choosing between the two machines for long-term, sustainable cardio and you’re prone to joint issues, the StairMaster or an incline treadmill walk will give you comparable calorie burn with far less stress on your joints.
How to Maximize Burn on Either Machine
On the StairMaster, the single most important thing is to stop leaning on the handrails. Light fingertip contact for balance is fine, but resting your weight on the rails can reduce your actual calorie burn by 20% or more compared to what the screen displays. Stand upright, engage your core, and let your legs do the work.
On the treadmill, adding incline is the fastest way to close the calorie gap. Even a 5% grade makes a noticeable difference. Interval training, alternating between high-speed or high-incline bursts and recovery periods, also increases total calorie expenditure and keeps your heart rate elevated after the workout ends. A 30-minute interval session on a treadmill can burn as many calories as 30 steady-state minutes on a StairMaster, with the added benefit of a longer post-exercise metabolic boost.