Convert Calories to Watt-hours
1 calorie (cal) equals 0.001162222222 watt-hours (Wh).
1 cal = 0.001162222222 Wh
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk calorie to watt-hour converter to paste a column from Excel.
How to Convert Calorie to Watt-hour
- 1 cal = 0.001162222222 Wh
- 1 Wh = 860.4206501 cal
- Example: convert 15 cal to Wh: 15 cal = 15 × 0.001162222222 Wh = 0.01743333333 Wh
Reference conditions. cal: Thermochemical calorie, 4.184 J exactly. The International Table calorie is 4.1868 J.
Formula
Wh = cal × 0.001162222222222
or Wh = cal ÷ 860.4206500956
Derivation from SI units:
- 1 cal (thermochemical) = 4.184 J (exact)
- 1 Wh = 1 W × 3600 s = 3600 J
- 1 cal = 4.184 J ÷ 3600 J per Wh = 0.001162222222222 Wh
Both units are defined exactly, so the factor is exact. Calorie definition: calorie; Watt-hour definition: watt-hour.
Worked examples
- A reading of 100 cal converts to 0.1162222222 Wh.
100 cal × 0.001162222222 = 0.1162222222 Wh - A value of 1000 cal is 1.162222222 Wh.
1000 cal × 0.001162222222 = 1.162222222 Wh
Calorie to Watt-hour conversion table
| Calories (cal) | Watt-hours (Wh) |
|---|---|
| 1 cal | 0.001162222222 Wh |
| 10 cal | 0.01162222222 Wh |
| 100 cal | 0.1162222222 Wh |
| 250 cal | 0.2905555556 Wh |
| 500 cal | 0.5811111111 Wh |
| 1000 cal | 1.162222222 Wh |
| 4184 cal | 4.862737778 Wh |
| 10000 cal | 11.62222222 Wh |
Where it's used
Calories are used for chemistry and calorimetry, while watt-hours appear in battery capacity (phone ≈ 15 Wh; airline limit 100 Wh per power bank). Both measure energy, work and heat, so the conversion is a fixed factor.
Calorie to other energy units
| Conversion | 1 cal equals |
|---|---|
| calorie to joule | 4.184 J |
| calorie to kilojoule | 0.004184 kJ |
| calorie to megajoule | 0.000004184 MJ |
| calorie to kilocalorie | 0.001 kcal |
| calorie to watt-hour | 0.001162222222 Wh |
| calorie to kilowatt-hour | 0.000001162222222 kWh |
| calorie to BTU | 0.003965666831 BTU |
| calorie to therm | 3.966613703 × 10⁻⁸ thm |
| calorie to electronvolt | 2.611447397 × 10¹⁹ eV |
| calorie to foot-pound | 3.085960033 ft·lbf |
| calorie to erg | 41840000 erg |
Frequently asked questions
How many watt-hours are in 1 calorie?
1 cal = 0.001162222222 Wh.
How do I convert calories to watt-hours?
Multiply the value in cal by 0.001162222222, or divide it by 860.4206501. For example, 15 cal × 0.001162222222 = 0.01743333333 Wh.
Is the cal to Wh conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "calorie (thermochemical) (cal_th)".
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "watt hour (W·h)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Calories to Watt-hours. Retrieved October 17, 2026, from https://scientificconverters.com/energy/calories-to-watt-hours/
IEEE
Scientific Converters, "Convert Calories to Watt-hours," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/calories-to-watt-hours/