Stationary Bike Calorie Calculator

Thirty minutes on a stationary bike at 90 to 100 watts costs a 70 kg rider about 220 kcal, and an hour about 441. Hold 200 watts instead and the hour is closer to 790. The calculator above uses the Compendium MET value for each wattage band, and because a bike is one of the few places you can read your actual work in watts, this page also shows the cross check that lets you skip the table entirely.

Stationary bike calorie calculator: calories per hour by watts

Compendium codes 01210, 01214, 01220, 01232, 01236 and 01240. By session length at 90 to 100 W:

The formula

kcal per minute = MET x 3.5 x body weight in kg / 200

For 70 kg at 90 to 100 W: 6.0 x 3.5 x 70 / 200 = 7.35 kcal per minute, 441 an hour. That is the sum the calculator prints, with the code, every time.

The better number, if you have watts

Here is the problem with the table on a bike: it scales with body weight, because MET values are per kilogram, so it says a 90 kg rider at 100 W burns half as much again as a 60 kg rider at the same 100 W, which on the road is partly true since the heavier rider has to move more mass up every rise. On a stationary bike nobody moves anywhere. Same 100 watts, same work. The calorie cost of that work depends on their efficiency, not their weight.

A power reading gives you the direct route. One watt for one second is one joule, so 100 W for an hour is 360 kJ, or 86 kcal, of mechanical work. Human legs turn food into pedal force at a gross efficiency of about 20 to 25 percent, so divide by that and you have the gross calorie cost.

The shortcut cyclists use is kcal per hour equals watts times 3.6, which assumes about 24 percent efficiency, and it sits inside that band. Compare it with the MET rows: 100 W at 70 kg gives 441 from the table and 344 to 430 from the watts. Same ballpark. The watt figure is the one that does not change when you type a different weight, though at low power it undershoots, because efficiency falls away and the resting cost dominates, so below about 75 W the table is the better guide.

Both numbers are estimates

The MET rows describe an average person of that weight in a lab, and the watt route assumes an efficiency you have not measured. Trained cyclists tend toward the top of the efficiency band, newer riders the bottom, and a 5 percent swing in efficiency is a 20 percent swing in calories. The console adds its own layer: many bikes estimate calories from resistance level and cadence rather than measured power, some assume a default weight, and a spin bike with no power meter is guessing at the watts to begin with. A wrist tracker reads heart rate, which climbs in a hot room even when the watts do not. In independent tests wrist devices have missed energy expenditure by a quarter or more.

All of the figures are gross. They include the roughly 1 MET, about 74 kcal an hour at 70 kg, you would have spent sitting on a sofa. Subtract it, or subtract 1 from the MET, when you eat the session back. The calories burned calculator shows gross and net together.

Where the number goes

A trainer session is a line in the day's budget. Set the budget with the TDEE calculator, size the cut with the calorie deficit calculator, and use the net figure rather than the gross one if you eat any of it back. The outdoor version, per kilometre rather than per minute, is the cycling calories page. The machine next to the bike has its own page too, the rowing calorie calculator, and the MET calculator holds the full table of 46 values.

How Movement Rebels fits

If your trainer or your bike computer records to Garmin Connect, or the ride reaches Apple Health from an iPhone, the coach in Movement Rebels reads it when it syncs, with duration, average and normalized power, TSS, intensity factor and per-lap power. That is measured work, and the coach uses it as training load when it plans the week and in the post-ride debrief. It reads your ride, not the average rider's.

The coach cannot see what you eat. Rebel Fuel is your own log and nothing from it reaches the coach, so it will not compare intake to what you rode off. If you are cutting, write it in the notes for your coach, and it will read a rising resting heart rate or a falling HRV as a fuelling signal rather than lost fitness. For how to keep strength and power while the scale drops, read Training on a Calorie Deficit.

MET values used here

Every value below is quoted from the Compendium of Physical Activities with its activity code, so you can look up the entry yourself. One MET is the oxygen cost of sitting quietly, about 3.5 ml of oxygen per kg per minute.

Walking and hiking

Treadmill walking

Running

Curved (non-motorised) treadmill running

Cycling

Stationary cycling

Rowing machine

Swimming

Strength and gym

Source: Compendium of Physical Activities (Ainsworth et al.), pacompendium.com. Codes are the Compendium's own.

Questions

More power & cycling tools