Joules to Watts
With joules or watts 3600, over how long 60 s, joules to watts comes to 60.000 W — watts. It is reached in 5 steps, the last of which is 3600 / 60, and each one is printed on the page with its numbers filled in. The formula is the one published by BIPM SI Brochure, 9th edition, not an approximation fitted to it.
A watt is a joule per second, so the conversion is a division by the time. Works either direction, and in kJ, kWh and calories.
Formula and sources checked · How we check
I know the Energy in joules — find the power, Joules or watts 3600, Over how long 60 s
60.000 W
Watts for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.
It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.
- Energy
1 * 3600 + 0 * (3600 * 60)3,600 J- Power
3600 / 6060 W- In kilojoules
3600 / 10003.6 kJ- In kilowatt-hours
3600 / 36000000.001 kWh- In food calories
3600 / 41840.86 kcal
Worked example
3,600 joules delivered over a minute is 60 watts. The same energy released in a hundredth of a second — a camera flash, near enough — is 360 kilowatts, which is the whole point of the distinction between energy and power.
How to work it out yourself
- 1.Give the duration. Joules measure a quantity of energy and watts a rate, so nothing converts without knowing how long the delivery took.
- 2.For a battery or a capacitor discharge, the seconds are the discharge time. For an appliance, they are the running time.
- 3.The kWh line is for anything large: 3.6 million joules is one kilowatt-hour, so a domestic bill in joules would run to eight digits per unit.
- 4.The calorie line uses the thermochemical calorie, exactly 4.184 J. A food label’s "calorie" is a kilocalorie, which is what this column gives.
Joules to watts over one minute
| Joules or watts | Watts | In kilojoules |
|---|---|---|
| 100 | 1.667 W | 0.1 kJ |
| 500 | 8.333 W | 0.5 kJ |
| 1000 | 16.667 W | 1 kJ |
| 2000 | 33.333 W | 2 kJ |
| 3600 | 60.000 W | 3.6 kJ |
| 5000 | 83.333 W | 5 kJ |
| 10000 | 166.667 W | 10 kJ |
| 20000 | 333.333 W | 20 kJ |
| 50000 | 833.333 W | 50 kJ |
| 100000 | 1,666.667 W | 100 kJ |
| 500000 | 8,333.333 W | 500 kJ |
A watt is exactly one joule per second, so a joule figure spread over 60 seconds gives a wattage sixty times smaller. 3,600 J over a minute is 60 W — the same 3,600 J over one second would be 3.6 kW.
The formula
- Energy
1 * 3600 + 0 * (3600 * 60) - Power
3600 / 60 - In kilojoules
3600 / 1000 - In kilowatt-hours
3600 / 3600000 - In food calories
3600 / 4184
Source: BIPM SI Brochure, 9th edition — the watt as one joule per second, NIST SP 811 — the thermochemical calorie as exactly 4.184 J
Questions people actually ask
- How do you convert joules to watts?
- Divide by the number of seconds. 3,600 J over 60 s is 60 W. A watt is defined as one joule per second, so the conversion is the definition read backwards.
- How do you convert watts to joules?
- Multiply by the seconds. A 60 W bulb for one minute uses 3,600 J. The unit "watt-second" and the joule are the same thing, which is why capacitor and flash ratings use them interchangeably.
- How many joules in a kWh?
- 3,600,000 exactly. One kilowatt is 1,000 J/s and an hour is 3,600 s, so the product is 3.6 MJ. Nothing here is measured or rounded — both units are defined.
- Is a joule the same as a calorie?
- No. One thermochemical calorie is exactly 4.184 joules, and the "calorie" on a food label is a kilocalorie — 4,184 J. A 2,000 kcal daily diet is 8.4 MJ, or about 2.3 kWh, which is roughly what a fridge uses in a day.
- Why do camera flashes use watt-seconds?
- Because a flash is a fixed amount of energy dumped in a very short time, and the peak wattage is enormous and useless as a rating. A 300 Ws flash stores 300 J; released over 1/1000 s that is 300 kW instantaneously, which describes nothing a photographer needs to know.
Related
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- Kinetic Energy CalculatorKinetic energy from mass and speed, with the stopping distance it implies — because the square on the velocity is the part that surprises people.
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