How this calculator works
Calories here are thermochemical: 1 cal = 4.184 J. A food Calorie is a kilocalorie, or 1,000 small calories. BTU uses the International Table convention (1,055.05585262 J).
The formula
Base amount = value × source factor
Target amount = base amount / target factorA quick example
1 kWh = 3,600,000 J; 1 food Calorie = 1 kcal = 4,184 J.
How to use this calculator
- Enter a value using a decimal point.
- Choose the source and target units.
- Read the live result or swap units to reverse the direction.
A few common questions
Which convention does this converter use?
Calories here are thermochemical: 1 cal = 4.184 J. A food Calorie is a kilocalorie, or 1,000 small calories. BTU uses the International Table convention (1,055.05585262 J).
Can I reverse the conversion?
Yes. Swap exchanges the units, keeps your input amount and calculates again.
Why is the displayed result rounded?
The calculation uses the full stored factor. Results show up to six decimal places, with scientific notation for very small or large amounts.
Reference: NIST conversion factors