Question 1

How do you convert joules to watts?

Accepted Answer

Divide the joules by the number of seconds: W = J ÷ s. Example: 3,600 J released over 60 seconds is 60 W. The reverse is J = W × s, so a 60 W bulb running for one minute consumes 3,600 J.

Question 2

Is a joule the same as a watt?

Accepted Answer

No. A joule is a quantity of energy; a watt is the rate that energy flows, defined as exactly one joule per second. The relationship is the same as the one between kWh and kW, just at a much smaller scale: in fact one kWh is 3.6 million joules.

Question 3

How many joules is 1 kWh?

Accepted Answer

Exactly 3,600,000 joules, or 3.6 megajoules. One kilowatt is 1,000 joules per second, and an hour is 3,600 seconds, so 1,000 × 3,600 gives 3.6 million. That is why joules are rarely used on utility bills: the numbers get unwieldy fast.

Question 4

Why does the calorie figure look small?

Accepted Answer

Because the converter shows food calories, which are actually kilocalories: 4,184 joules each, not 4.184. Nutrition labels have used the capital-C Calorie for the kilocalorie for over a century, while physics uses the small calorie. The result is that 3,600 J is 860 small calories but only 0.86 food calories.

Joules to Watts Calculator

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