Watt-hours to Calories Converter
1 watt-hour ≈ 860.42065 calories
This is the small calorie. The "Calorie" on food labels is a kilocalorie, which is 1,000 of these.
1 watt-hour equals 860.421 calories
How to convert watt-hours to calories
Calories here are thermochemical (4.184 J), while BTU uses the International Table definition. A kilowatt-hour is energy (3.6 MJ), not power; a food Calorie is a kilocalorie.
cal = Wh × 860.4206501One watt-hour is 860.4206501 calories, so a single multiplication converts any value.
8,604.21 cal ≈ 10 × 860.4206501This is the small calorie. The "Calorie" on food labels is a kilocalorie, which is 1,000 of these.
Watt-hours to calories conversion table
Common values in watt-hours, converted to calories.
| Watt-hours (Wh) | Calories (cal) |
|---|---|
| 1 | 860.42065 |
| 2 | 1,720.8413 |
| 3 | 2,581.262 |
| 4 | 3,441.6826 |
| 5 | 4,302.1033 |
| 10 | 8,604.2065 |
| 20 | 17,208.413 |
| 25 | 21,510.516 |
| 50 | 43,021.033 |
| 100 | 86,042.065 |
| 250 | 215,105.16 |
| 500 | 430,210.33 |
| 1,000 | 860,420.65 |
About these units
watt-hourWh
One watt sustained for one hour: exactly 3,600 joules.
caloriecal
The thermochemical calorie: exactly 4.184 joules.
Reference: NIST Special Publication 811.
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.