Watts to Joules
Joules to Watts

15 Joules to Watts

Joules measure energy and watts measure power, so the answer depends on time. Here is the wattage required to expend 15 J over each period.

15 joules equals

15 W (over 1 second)

Because 1 watt = 1 joule per second, expending 15 J in exactly 1 second requires a power of 15 W.

Over 1 minute
0.25 W
Over 1 hour
0.00416667 W
Over 1 day
1.736e-4 W

15 joules to watts, explained

A watt is a rate of energy transfer: one watt means one joule of energy is transferred every second. Therefore, to find out how many watts 15 joules equals, you must know how fast that energy is used.

For example, releasing 15 J over one hour (3,600 seconds) requires 15 ÷ 3,600 = 0.00416667 W. Releasing it slowly over a full day only requires 1.736e-4 W.

watts = 15 J ÷ time in seconds

Need a different energy or time? Use the interactive converter below for any combination.

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15 J power over time

Power required to expend 15 J over common time periods.
Time periodPower (watts)
1 second15 W
1 minute0.25 W
10 minutes0.025 W
1 hour0.00416667 W
6 hours6.944e-4 W
1 day1.736e-4 W

Convert any energy and time

The full Joules to Watts converter handles J, kJ, MJ, any time unit, and the reverse watts→joules calculations.

Open the converter →

Frequently asked questions

How many watts is 15 joules?

15 joules does not equal a fixed number of watts. Joules measure energy and watts measure power. To find watts, you must divide the joules by the time in seconds. For example, 15 J over 1 second is 15 W.

How do you convert 15 joules to watts?

Divide the 15 joules by the number of seconds the energy is released over. Power (W) = Energy (J) ÷ Time (s). If the time is 1 hour (3,600 seconds), it is 15 ÷ 3,600 = 0.00416667 W.