Cycling Calories Calculator

Work in kilojoules is average power in watts times the duration in seconds, divided by 1000. That kilojoule figure is divided by your metabolic efficiency and then by 4.184 to convert kilojoules into kilocalories. So 200 watts for two hours is 1,440 kJ, which at 0.24 efficiency comes to about 1,434 calories.

Human pedalling is roughly 24 percent efficient, meaning most of your metabolic energy becomes heat rather than motion. Dividing the kilojoules by 0.24 and then by 4.184 leaves a multiplier very close to one, so the calorie total lands near the raw kilojoule number. It is a handy coincidence, not an exact rule.

A figure between 0.20 and 0.25 covers most cyclists, and 0.24 is a sensible default. Well-trained riders tend toward the top of that band. A higher efficiency means your body wastes less energy as heat, so the calorie estimate goes down for the same work.

Work in kilojoules is the pure mechanical energy delivered to the pedals, and it does not depend on efficiency. Calories are the metabolic energy your body had to spend to produce that work, which is always larger because muscles are not fully efficient. The tool shows both so you can log whichever your platform expects.

When you have a power meter, yes. Power is a direct measurement of the work you did, while heart-rate and speed models infer effort from indirect signals that drift with heat, fatigue, wind, and terrain. Without a power meter you would need one of those estimate-based calculators instead.

No. It estimates only the extra energy used to ride the bike. Your body also burns baseline calories to stay alive, which a basal metabolic rate calculator handles separately, so do not expect this number to match a fitness tracker that folds in resting metabolism.

The Duration field expects minutes, so convert first: multiply hours by 60 or divide seconds by 60. A 90 minute ride is entered as 90, and a 45 second effort would be 0.75.

Power and duration must be positive numbers, and efficiency must be greater than 0 and no more than 1. Blank fields, zero, negatives, or an efficiency above 1 produce a short prompt to fix the value rather than a result.

Yes. The calculation runs entirely in your browser, so the watts and minutes you type never leave your device or reach a server. You can use it offline once the page has loaded.