Last updated July 2026.
You finish a treadmill session, look at the console, and see a big satisfying number. Here’s the uncomfortable part: it’s probably too high. Not because the machine is broken, but because of how it’s built to estimate in the first place.
The Study Behind This Claim
In testing at UC San Francisco’s Human Performance Center, researchers put cardio machines up against laboratory-grade measurement and compared the results. Across the board, the machines ran high. Cardio equipment overestimated calorie burn by roughly 19% on average. Treadmills specifically ran about 13% high. Stationary bikes were the most accurate, still overestimating by around 7%. Ellipticals were the worst offender, running over 40% high.
Put a real number on that: if you did a session your treadmill says burned 400 calories, the honest figure is closer to 350. That’s not a rounding error, it’s the difference between an actual calorie deficit and a smaller one than you think you’re running.
Why the Console Gets It Wrong in the First Place
It’s Calibrated to a Stranger
Most treadmill consoles are built around a reference body, commonly somewhere in the 150 to 160 lb range. Unless you’ve manually entered your real weight, the console is calculating your session as if you were that reference person. If you weigh more, it under-credits you. If you weigh less, it over-credits you.
It Can’t See What Your Hands Are Doing
Consoles have no way of detecting whether you’re gripping the handrails. Holding on measurably reduces how much work your legs are doing (we cover the exact peer-reviewed numbers on our handrail effect page), but the console still reports the number as if your body weight alone were doing the work.
It Doesn’t Know Your Fitness Level
A trained runner is typically more efficient, meaning they burn somewhat less energy to cover the same distance at the same pace than an untrained person. Generic formulas built into consoles don’t adjust for this.
So What Should You Actually Do With the Number?
Don’t throw it out entirely, it’s still useful as a relative signal. Use it (or a calculator built on documented formulas, like the one on this site) to compare session to session, rather than treating any single number as a precise fact. And if you’re using calorie burn to plan how much to eat back on a deficit, build in a margin, don’t eat back 100% of whatever the console claims.
Related Reading
- Treadmill vs. Apple Watch, Fitbit & Garmin: why the numbers never match
- The handrail effect, with the real study numbers
- Our full calculation methodology
Sources
- UC San Francisco Human Performance Center, cardio machine calorie accuracy testing (as reported by Salon and ABC News/Good Morning America).