Convert watts and duration to calories, joules, and watt-hours, estimate cycling food Calories with efficiency, or find watts for a calorie target.
Watts to Calories Formula
Use the formula below to convert power and time into calories. To convert the result into food calories, divide by 1,000.
C = W × s × 0.239005736
Variables:
- C = calories (cal)
- W = power in watts
- s = time in seconds
Watts measure how quickly energy is used. Time turns that rate into a total, so doubling the watts or doubling the time doubles the calories.
Quick Conversion Facts
- 1 watt for 1 second = 0.2390 cal
- 100 watts for 60 seconds = 1,434.03 cal = 1.4340 kcal
- 250 watts for 10 minutes = 35,850.86 cal = 35.8509 kcal
- 500 watts for 5 minutes = 35,850.86 cal = 35.8509 kcal
- 1,000 watts for 60 seconds = 14,340.34 cal = 14.3403 kcal
Common Watts to Calories Conversions
| Power (W) | Time | Calories (cal) | Food Calories (kcal) |
|---|---|---|---|
| 50 | 60 s | 717.02 | 0.7170 |
| 100 | 60 s | 1,434.03 | 1.4340 |
| 250 | 60 s | 3,585.09 | 3.5851 |
| 100 | 300 s | 7,170.17 | 7.1702 |
| 250 | 300 s | 17,925.43 | 17.9254 |
| 500 | 300 s | 35,850.86 | 35.8509 |
| 100 | 600 s | 14,340.34 | 14.3403 |
| 250 | 600 s | 35,850.86 | 35.8509 |
| 500 | 600 s | 71,701.72 | 71.7017 |
| kcal values are food calories. | |||
How to Calculate Calories from Watts
- Enter the power in watts.
- Enter the time in seconds, or switch to the Advanced tab for minutes or hours.
- Multiply watts by time to get total energy, then convert that result into calories.
- Read the result in calories (cal) and food calories (kcal).
Example Calculation
If power is 200 watts and time is 90 seconds:
C = 200 × 90 × 0.239005736 = 4,302.10
That equals 4,302.10 cal, or 4.3021 kcal.