Exercise bike calorie calculator

How the calculator works

If your bike shows your power, the calculator starts with the work you did on the pedals. Power in watts times the time you rode gives that work in kilojoules (kJ). Your body turns only about a fifth of the energy it uses into pedal power. The rest turns into heat. That is why 1 kJ of work comes out at roughly 1 calorie burned.

Food labels say kcal or calories. They mean the same thing, and so does this calculator.

No power reading? Then it uses your weight and how hard the ride felt. Each feeling has an effort score called a MET. One MET is the energy you use sitting still. A score of 6 means you burn six times that.

How close the answer is

The power way is the closer of the two. People differ a little in how well they turn food into pedal power, so the calculator shows a range too. The feel way is a rough guess, because two people can feel the same ride in very different ways.

Fitness watches and gym bikes often show their own number. Each one uses its own sums, so treat any of them as a guide.

Where the numbers come from

• The link between kJ and calories comes from TrainingPeaks. It says riders turn 20 to 25% of their energy into work, and uses the middle, 22.5%. The range on the calculator uses 20% and 25%.
• The effort scores are from the 2024 Adult Compendium of Physical Activities, a list of how much energy everyday activities use. Each feeling matches the Compendium's own effort words for indoor cycling. Easy is code 01214 (4.0), moderate is 01220 (6.0), hard is 01236 (10.8) and very hard is 01240 (12.5).
• The sum that turns an effort score into calories is on the Compendium's unit conversions page: MET times 3.5 times your weight in kg, divided by 200, gives calories a minute.