How this calculator works

The speed mode uses metabolic equivalent (MET) values for cycling from the 2024 Adult Compendium of Physical Activities, the reference dataset researchers use to quantify the energy cost of exercise. Gentle riding below 16 km/h rates 4.0 METs, 16 to 19 km/h rates 6.8, 19 to 22.5 km/h rates 8.0, 22.5 to 25.5 km/h rates 10.0, 25.5 to 30.5 km/h rates 12.0, and racing beyond 32 km/h rates around 16. Mountain biking on mixed trails sits near 8.5. Your calories are then METs multiplied by your weight in kilograms multiplied by hours ridden.

The watts mode is the one to trust if you ride with a power meter or a smart trainer. In cycling, the kilojoules of work your power meter records roughly equal the kilocalories your body burned, because human mechanical efficiency of around 24% almost exactly cancels out the unit conversion. So an hour at 200 watts costs you about 720 kcal regardless of wind, hills or drafting, which is exactly what speed-based estimates cannot see.

Calories burned cycling by speed

For a 70 kg rider, an hour of gentle riding under 16 km/h burns around 280 kcal, an hour at a commuting pace of 16 to 19 km/h burns around 480 kcal, an hour at a moderate 19 to 22 km/h burns around 560 kcal, a brisk hour at 22.5 to 25.5 km/h burns around 700 kcal, and a fast hour at 25.5 to 30.5 km/h burns around 840 kcal. Heavier riders burn proportionally more: at 85 kg, add roughly a fifth to every figure above, and at 60 kg, take roughly a seventh off. Hills, headwinds, rough surfaces and a loaded bike all push the true cost higher, often by 10 to 20%.

Calories burned by distance

Distance answers depend on how fast you cover it, but at a moderate club pace a 70 kg rider spends around 430 kcal on a 10 mile ride, around 1,450 kcal on 50 km, around 2,900 kcal on a 100 km sportive, and around 4,700 kcal on a 100 mile century. Those last two numbers are why long-ride fuelling goes wrong so often: a century can cost you two full days of food in a single ride.

Indoor, turbo and e-bike rides

A moderate indoor session on a stationary bike or turbo burns roughly what a 19 to 22 km/h outdoor ride does, but speed means little indoors, so use the watts mode: smart trainers report power directly and it is the most reliable number you have. On an e-bike, the motor covers a share of the work, so your burn drops meaningfully with higher assistance levels; treat e-bike rides as one to two speed bands easier than the speed on your display suggests.

Why your number is an estimate

MET values are population averages measured on flat ground, and they report gross calories, which include what you would have burned sitting still for the same time. Your fitness, position on the bike, terrain and the weather all move the real figure. Power-based numbers are tighter, usually within about 5%, which is why serious riders fuel from kilojoules. Use the estimate to plan, then adjust with experience.

Refuelling what the ride costs

Burning 600 to 900 kcal an hour is easy on a bike. Eating it back mid-ride is the hard part, because appetite fades and jersey pockets are small. Sports nutrition guidance is to take on 30 to 60g of carbohydrate per hour for rides up to about three hours, and 45 to 90g per hour beyond that, from high-carb solid foods, drinks and gels your stomach can handle. Calorie density is what decides how much fuel you can actually carry: our high calorie energy bars pack 557 kcal into a single 120g bar, 4.64 kcal per gram, so one bar in a jersey pocket replaces the best part of an hour's riding. For multi-hour efforts, see our guides to long-distance cycling nutrition and gravel cycling nutrition, our pick of the best energy bars for long-distance cycling, and the highest calorie bars in the UK ranked by energy per gram.

Frequently asked questions

How many calories does 30 minutes of cycling burn? For a 70 kg rider, roughly 140 kcal riding gently, 280 kcal at a moderate pace, and 420 kcal riding hard. Scale up or down with your body weight.

How many calories does an hour of cycling burn? Between about 280 and 840 kcal for a 70 kg rider depending on pace, and more again when racing. Watts settle it precisely: multiply your average power by 3.6 to get kcal per hour.

How many calories does a 10 km ride burn? At a moderate pace a 10 km ride takes around half an hour and costs a 70 kg rider roughly 250 to 300 kcal.

How many calories should I eat when cycling? For rides up to about three hours, aim for 30 to 60g of carbohydrate per hour, and for longer rides 45 to 90g per hour, starting early rather than waiting until you feel empty. Under-fuelling long rides is far more common than over-fuelling them.

What is the 75 rule in cycling? A training guideline that around 75% of your weekly riding should sit at or below 75% of your maximum heart rate. Easy riding still burns plenty over time, and it is the volume most riders can sustain.

Can I lose weight cycling? Weight change comes down to overall energy balance across weeks, not single rides. A kilogram of body fat represents roughly 7,700 kcal, so consistent riding shifts weight when your diet does not replace the full burn. Plenty of endurance riders have the opposite problem, struggling to eat enough on big training weeks, which is where calorie-dense food earns its place.

Written by James, founder of Flaming Phoenix and the maker of Phoenix Bars. Calculator methodology based on the 2024 Adult Compendium of Physical Activities. Updated August 2026.