Cycling Watts to Calories Per Hour: Complete Reference Guide
How many calories does one watt burn per hour cycling? The answer is 3.6 kcal. See the full watts-to-calories-per-hour table from 50W to 400W.
One watt of cycling power burned for one hour equals approximately 3.6 kcal. At 100 watts you burn 360 kcal/hr, at 150 watts you burn 540 kcal/hr, and at 200 watts you burn 720 kcal/hr. The relationship is perfectly linear — every additional watt adds 3.6 kcal to your hourly burn.
Use our Cycling Watt Calorie Calculator to calculate your total calories for any wattage and duration, or use the reference tables below.
How Many Calories Is One Watt Per Hour?
One watt sustained for one hour burns 3.6 kcal. This is not an approximation — it is derived directly from physics and average human cycling efficiency:
- 1 watt = 1 joule per second
- Over one hour: 1W × 3,600 seconds = 3,600 joules of mechanical work
- 3,600 joules ÷ 4,184 joules/kcal = 0.86 kcal of mechanical energy
- At ~24% human cycling efficiency: 0.86 ÷ 0.24 = 3.58 kcal ≈ 3.6 kcal
This factor holds across all rider weights, speeds, and terrains — because it is based on mechanical work output, not body mass or velocity.
Watts to Calories Per Hour Reference Table
Find your average power in the left column to see your calorie burn rate per hour.
| Power (watts) | kcal per Hour | kcal per 30 min | kcal per 45 min |
|---|---|---|---|
| 50W | 180 kcal/hr | 90 kcal | 135 kcal |
| 75W | 270 kcal/hr | 135 kcal | 203 kcal |
| 100W | 360 kcal/hr | 180 kcal | 270 kcal |
| 125W | 450 kcal/hr | 225 kcal | 338 kcal |
| 150W | 540 kcal/hr | 270 kcal | 405 kcal |
| 175W | 630 kcal/hr | 315 kcal | 473 kcal |
| 200W | 720 kcal/hr | 360 kcal | 540 kcal |
| 225W | 810 kcal/hr | 405 kcal | 608 kcal |
| 250W | 900 kcal/hr | 450 kcal | 675 kcal |
| 275W | 990 kcal/hr | 495 kcal | 743 kcal |
| 300W | 1,080 kcal/hr | 540 kcal | 810 kcal |
| 325W | 1,170 kcal/hr | 585 kcal | 878 kcal |
| 350W | 1,260 kcal/hr | 630 kcal | 945 kcal |
| 375W | 1,350 kcal/hr | 675 kcal | 1,013 kcal |
| 400W | 1,440 kcal/hr | 720 kcal | 1,080 kcal |
The Formula: Calories Per Hour = Watts × 3.6
The formula for hourly calorie burn rate is:
Calories per Hour = Watts × 3.6
For total calories over any ride duration:
Total Calories = Watts × Hours × 3.6
Quick examples:
- 180W for 45 minutes: 180 × 0.75 × 3.6 = 486 kcal
- 220W for 1 hour: 220 × 1 × 3.6 = 792 kcal
- 160W for 2 hours: 160 × 2 × 3.6 = 1,152 kcal
For the complete formula explanation, worked examples table, and reverse conversion (calories → watts), see the full Watts to Calories Cycling Guide.
Watts to Calories Per Minute
To convert watts to calories burned per minute, divide the hourly rate by 60:
Calories per Minute = Watts × 3.6 ÷ 60 = Watts × 0.06
| Power (watts) | kcal per Minute |
|---|---|
| 100W | 6.0 kcal/min |
| 150W | 9.0 kcal/min |
| 200W | 12.0 kcal/min |
| 250W | 15.0 kcal/min |
| 300W | 18.0 kcal/min |
Watts to Calories Per Second
For scientific purposes or interval analysis, per-second conversion:
Calories per Second = Watts × 3.6 ÷ 3,600 = Watts × 0.001
At 200 watts, you burn 0.2 kcal per second of sustained effort. Over a 30-second sprint, that is 6 kcal of mechanical-equivalent energy — though sprint efforts involve significant anaerobic contribution that the formula does not capture directly.
How This Compares to Speed-Based Calorie Estimates
Speed-based calorie calculators use MET (Metabolic Equivalent of Task) values combined with body weight:
Calories = MET × Body Weight (kg) × Hours
At moderate cycling pace (~20 km/h), MET ≈ 7.5. For a 75 kg rider over 1 hour: 7.5 × 75 × 1 = 563 kcal.
This same rider, if producing 170W at that speed: 170 × 3.6 = 612 kcal/hr.
The difference reflects two things: (1) MET values are population averages that do not account for individual fitness levels, and (2) the same speed requires different power depending on wind, gradient, and bike setup. Power-based calculation is more precise when you have a power meter, because it measures actual mechanical work rather than estimating it from speed.
Watts to Calories by Training Zone
Every cycling training zone corresponds to a different calorie burn rate. Your zones are based on your FTP (Functional Threshold Power) — the maximum power you can sustain for approximately one hour.
| Training Zone | % of FTP | Example Watts* | kcal per Hour |
|---|---|---|---|
| Zone 1 – Recovery | < 55% | < 138W | < 497 kcal/hr |
| Zone 2 – Endurance | 56–75% | 140–188W | 504–677 kcal/hr |
| Zone 3 – Tempo | 76–90% | 190–225W | 684–810 kcal/hr |
| Zone 4 – Threshold | 91–105% | 228–263W | 821–947 kcal/hr |
| Zone 5 – VO2max | 106–120% | 265–300W | 954–1,080 kcal/hr |
| Zone 6 – Anaerobic | > 120% | > 300W | > 1,080 kcal/hr |
*Example watts based on 250W FTP
Use our FTP Calculator to determine your threshold power, then apply the watts × 3.6 formula to estimate the calorie burn for your specific training sessions.
Frequently Asked Questions
How many calories do you burn cycling at 150 watts for one hour? At 150 watts for one hour: 150 × 1 × 3.6 = 540 kcal. This corresponds to a moderate endurance pace (Zone 2) for most trained cyclists.
How many calories per watt per hour cycling? 3.6 kcal per watt per hour. This is the standard conversion factor for cycling power to calorie burn, derived from the physics of mechanical work and average human cycling efficiency (~24%).
Is the calorie burn the same for all body weights at the same wattage?
Yes, for the mechanical component. The formula Calories = Watts × Hours × 3.6 does not depend on body weight. A lighter and a heavier rider producing the same power output for the same duration burn the same number of watts-derived calories.
Do heavier cyclists burn more calories cycling? Heavier riders burn more calories to produce the same speed, because they must overcome greater rolling resistance and gravitational force on climbs. However, if two riders of different weights both produce 200W for 1 hour, they both burn approximately 720 kcal — power equalizes the comparison.
Get your exact number: Enter your average watts and ride duration into the Cycling Watt Calorie Calculator for your precise total calories and kcal/hr rate.