How do I convert joules back to calories?

Use the reverse converter: 1 joule equals 0.239006 cal.

Is this converter accurate?

Yes. It uses the exact SI/NIST definitions of each unit and shows up to 6 significant digits.

To convert calories to joules, multiply the value by 4.184.

J = cal × 4.184

40 cal × 4.184 = 167.36 J

Calorie (cal): The thermochemical calorie is exactly 4.184 joules, historically the heat to warm one gram of water by 1 °C.
Joule (J): The SI unit of energy, one newton-metre, named after James Prescott Joule.

How do I convert calories to joules?: To convert calories to joules, multiply the value by 4.184.
How many joules are in 1 calorie?: 1 calorie equals 4.184 J.
How many joules are in 10 calories?: 10 cal equals 41.84 J.
How do I convert joules back to calories?: Use the reverse converter: 1 joule equals 0.239006 cal.
Is this converter accurate?: Yes. It uses the exact SI/NIST definitions of each unit and shows up to 6 significant digits.