Calories (cal)
The calorie (small calorie) is the energy needed to raise the temperature of one gram of water by about one degree Celsius.
Convert calories to any energy unit
1 calorie = 4.184 joules
Quick facts
- Unit
- Calorie (plural: calories)
- Symbol
- cal
- Measures
- Energy / Work / Heat
- System
- Calories
- Equals
- 4.184 joules
- Definition
- Exactly 4.184 J (thermochemical calorie).
- Also written
- thermochemical calorie, small calorie, gram calorie, cal_th
1 calorie in other units
| Joules | 4.184 J |
| Kilocalories | 0.001 kcal |
| Kilowatt-hours | 0.000001162222 kWh |
| British thermal units | 0.003965666831 BTU |
| Kilojoules | 0.004184 kJ |
| Calories (food) | 0.001 Cal |
| Electronvolts | 2.6114474 × 1019 eV |
| Watt-hours | 0.001162222222 Wh |
What is a calorie?
The calorie (small calorie) is the energy needed to raise the temperature of one gram of water by about one degree Celsius. The thermochemical calorie used in chemistry and nutrition is defined as exactly 4.184 joules.
Food labels actually use the kilocalorie, 1,000 of these calories, often written Calorie with a capital C. So a "200 Calorie" snack contains 200,000 small calories.
Where the calorie sits among energy units
The calorie is number 28 of 99 on our scale of energy units, ordered from smallest to largest.
What calories are used for
- Chemistry and thermodynamics (older texts)
- Nutrition, as kilocalories
Calories in real life
- Warming 1 g of water by 1 °C takes about 1 cal
- A food Calorie is 1,000 calories
One calorie is about the energy of 4.2 apple lifts.
Top calorie conversions
Common amounts of calories
- 0.1 cal
- 0.2 cal
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- 3,000 cal
- 4,000 cal
- 5,000 cal
- 10,000 cal
Convert calories to all 98 other units
Metric (SI)
Electrical
Calories
- cal to kcal
- cal to Cal
- cal to cal_IT
- cal to Gcal
- cal to Mcal
- cal to cal₁₅
- cal to th
- cal to cal₂₀
- cal to cal_mean
BTU & therms
- cal to BTU
- cal to thm
- cal to MMBtu
- cal to MBtu
- cal to Dth
- cal to quad
- cal to thm (EC)
- cal to BTU_th
- cal to BTU₅₉
- cal to CHU
- cal to Q
- cal to BTU₃₉
- cal to BTU₆₀
- cal to BTU_mean
Mechanical
- cal to ft⋅lbf
- cal to erg
- cal to in⋅lbf
- cal to hp⋅h
- cal to L⋅atm
- cal to kgf⋅m
- cal to ft⋅pdl
- cal to in⋅ozf
- cal to PS⋅h
- cal to cm³⋅atm
- cal to ft³⋅atm
- cal to ft³⋅psi
Atomic & physics
- cal to eV
- cal to MeV
- cal to GeV
- cal to keV
- cal to TeV
- cal to Eh
- cal to kJ/mol
- cal to kcal/mol
- cal to meV
- cal to cm⁻¹
- cal to EP
- cal to PeV
- cal to Ry
- cal to EeV
- cal to K·k_B
- cal to foe
- cal to h·Hz
Fuel & explosive equivalents
- cal to BOE
- cal to t TNT
- cal to toe
- cal to kt
- cal to Mt
- cal to cubic foot of natural gas
- cal to GGE
- cal to Mtoe
- cal to cubic meter of natural gas
- cal to tce
- cal to ktoe
- cal to liter of gasoline
- cal to Gt
- cal to g TNT
- cal to kg TNT
- cal to MMBOE
- cal to kBOE
- cal to DGE
Everyday comparisons
Convert to calories
Frequently asked questions
What is a calorie?
The calorie (small calorie) is the energy needed to raise the temperature of one gram of water by about one degree Celsius.
How is the calorie defined?
Exactly 4.184 J (thermochemical calorie).
How many joules are in a calorie?
One calorie equals 4.184 joules.
How many kilocalories are in a calorie?
One calorie equals 0.001 kilocalories.
How many kilowatt-hours are in a calorie?
One calorie equals 0.000001162222 kilowatt-hours.