Do you burn fewer calories on an e-MTB?

Per hour, usually somewhat fewer, because the motor lowers your heart rate a little. Per ride, often similar or more, because e-MTB rides tend to be longer with more climbing.

How many calories does mountain biking burn per hour?

A common estimate uses 8.5 METs for general mountain biking from the Compendium of Physical Activities. Multiply by your weight in kg: an 80 kg rider gets roughly 680 calories per hour. Actual figures vary with terrain and effort.

How hard is an e-MTB workout compared with a regular mountain bike?

In a 2019 Brigham Young University study, average heart rate on an e-MTB was about 94 percent of that on a regular mountain bike over the same loop, with most of the ride at vigorous intensity on both.

Are e-bike calorie readings accurate?

Not very. Unless the bike is paired with a heart-rate sensor it cannot measure your effort, and even then it gives an estimate. A chest heart-rate strap gives a better picture.

e-MTB vs MTB calories: how much do you really burn?

The short answer

An hour on an e-MTB usually burns somewhat fewer calories than an hour on a regular mountain bike at the same effort level you would naturally choose, because the motor lowers your heart rate a little. But calories come from effort multiplied by time, and e-MTB rides tend to be longer with more climbing. Over a whole ride, the totals are often similar, and sometimes higher on the e-bike.

Exact numbers depend on your weight, the terrain, the assist mode and how hard you push. Anyone giving you one figure for "calories burned on an e-bike" is guessing.

What the heart-rate studies show

Calories track effort, and heart rate is the easiest way to measure effort on a trail. In a 2019 Brigham Young University study, experienced riders rode the same loop on a regular mountain bike and on a pedal-assist e-MTB. On the e-MTB their average heart rate was about 94 percent of their regular-bike heart rate. Most of the ride on both bikes was spent at a vigorous intensity.

So per minute, the e-MTB took a bit less effort, but not much less. More on the research in is riding an e-bike good exercise?

A simple way to estimate

Exercise scientists estimate energy use with METs, a multiple of your resting energy use. The Compendium of Physical Activities lists general mountain biking at 8.5 METs. A rough calorie estimate is:

calories per hour ≈ METs × your weight in kg

For an 80 kg (176 lb) rider, general mountain biking comes out around 680 calories per hour. For an e-MTB ride, a reasonable working assumption is a somewhat lower figure per hour, depending on how much assist you use. In eco mode on steep terrain you may be close to the regular-bike number. In boost on gentle terrain you will be well under it.

Treat these as ballpark numbers, not measurements.

Why ride length matters more

Here is where e-MTBs often catch up:

More laps. Riders commonly do two or three climbs where they would do one on a regular bike.
Longer rides. The motor reduces fatigue, so rides last longer before you call it.
More rides. Many people ride more often because each ride feels less punishing, which adds up across a week.

A two-hour e-MTB ride at a slightly lower intensity can easily burn more than a one-hour regular ride.

How to measure your own

Use a heart-rate strap. Wrist sensors struggle on rough trails. A chest strap is much more accurate.
Compare like with like. Same loop, similar conditions, both bikes if you can.
Look at the whole ride, not speed. Average heart rate and total time tell you more than distance.
Do not trust the e-bike display. Some bikes show a calorie figure, but they cannot see your heart rate unless you pair a sensor, and even then it is an estimate.

If you want to burn more on an e-MTB

Ride in the lowest assist mode that gets you up.
Add laps instead of riding faster.
Keep a steady cadence on climbs rather than letting the motor carry you.
Switch assist off on flat or gentle sections.

The honest bottom line

If calorie burn per minute is your only goal, a regular bike in a hard gear wins. If the goal is to ride more, enjoy it more and keep doing it, the e-MTB often ends up ahead over a month. Either way, you are pedalling.

More pedalling also means more sweat on the climbs, which is why I made the Watts tee: a light tee that dries faster than the shirt you grabbed on the way out.