Watts to Joules Calculator

Enter your Power in Watts (W) and Time in seconds (s) into the Watts to Joules Calculator to find the total Energy in Joules (J) — plus bonus conversions to kilowatt-hours (kWh) and calories (cal) so you've got every unit covered.

W

Power consumption in watts

s

Time duration in seconds

Results

Energy (J)

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Energy (kWh)

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Energy (cal)

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Frequently Asked Questions

How do you convert watts to joules?

To convert watts to joules, multiply the power in watts by the time in seconds. The formula is: Energy (J) = Power (W) × Time (s). For example, 100 watts for 60 seconds equals 6,000 joules.

What is the difference between watts and joules?

Watts measure power (energy per unit time), while joules measure energy. Watts tell you the rate of energy consumption, and joules tell you the total amount of energy used over a specific time period.

Why do I need to know time to convert watts to joules?

Because watts are a rate of energy consumption per second, you need to specify the duration to calculate the total energy consumed. Without time, you cannot determine the total energy in joules.

Can I convert joules back to watts?

Yes, to convert joules to watts, divide the energy in joules by the time in seconds: Power (W) = Energy (J) ÷ Time (s). This gives you the average power consumption over that time period.

What are common applications for watts to joules conversion?

This conversion is useful for calculating energy consumption of electrical devices, battery capacity requirements, heating calculations, and determining electricity costs based on power ratings and usage time.

How many joules are in one kilowatt-hour?

One kilowatt-hour (kWh) equals 3,600,000 joules. This is because 1 kW = 1,000 W and 1 hour = 3,600 seconds, so 1,000 W × 3,600 s = 3,600,000 J.

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