Enter the power and time into the calculator to determine the energy delivered in watt-seconds (W·s), which is equal to joules (J). This calculator can also evaluate any of the variables when the other two are known.
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Watt Seconds To Heat Formula
The following formula is used to calculate energy in watt-seconds (joules) delivered by a constant power over a period of time.
WSH = P * t
Variables:
- WSH is the energy in watt-seconds (W·s), which is equivalent to joules (J)
- P is the power in watts (W)
- t is the time in seconds (s)
To calculate watt-seconds, multiply the power in watts by the time in seconds. The result is the energy supplied (in joules). If essentially all of that supplied energy ends up as heat in an object (or you account for losses using an efficiency factor), it can be used to estimate heating. To calculate the heat needed for a temperature rise based on material properties, use the “Heat a Material” tab (which uses Q = m·c·ΔT).
| Joules (J) | Kilojoules (kJ) | Megajoules (MJ) | Watt-hours (Wh) | Kilowatt-hours (kWh) | BTU |
|---|---|---|---|---|---|
| 10 | 0.010 | 0.000010 | 0.002778 | 0.000003 | 0.009478 |
| 50 | 0.050 | 0.000050 | 0.013889 | 0.000014 | 0.047391 |
| 100 | 0.100 | 0.000100 | 0.027778 | 0.000028 | 0.094782 |
| 200 | 0.200 | 0.000200 | 0.055556 | 0.000056 | 0.189564 |
| 500 | 0.500 | 0.000500 | 0.138889 | 0.000139 | 0.473909 |
| 1000 | 1.000 | 0.001000 | 0.277778 | 0.000278 | 0.947817 |
| 2000 | 2.000 | 0.002000 | 0.555556 | 0.000556 | 1.895634 |
| 3600 | 3.600 | 0.003600 | 1.000000 | 0.001000 | 3.412142 |
| 5000 | 5.000 | 0.005000 | 1.388889 | 0.001389 | 4.739086 |
| 10000 | 10.000 | 0.010000 | 2.777778 | 0.002778 | 9.478171 |
| 20000 | 20.000 | 0.020000 | 5.555556 | 0.005556 | 18.956342 |
| 50000 | 50.000 | 0.050000 | 13.888889 | 0.013889 | 47.390856 |
| 100000 | 100.000 | 0.100000 | 27.777778 | 0.027778 | 94.781712 |
| 200000 | 200.000 | 0.200000 | 55.555556 | 0.055556 | 189.563424 |
| 360000 | 360.000 | 0.360000 | 100.000000 | 0.100000 | 341.214163 |
| 500000 | 500.000 | 0.500000 | 138.888889 | 0.138889 | 473.908560 |
| 1000000 | 1000.000 | 1.000000 | 277.777778 | 0.277778 | 947.817120 |
| 3600000 | 3600.000 | 3.600000 | 1000.000000 | 1.000000 | 3412.141632 |
| 10000000 | 10000.000 | 10.000000 | 2777.777778 | 2.777778 | 9478.171203 |
| 50000000 | 50000.000 | 50.000000 | 13888.888889 | 13.888889 | 47390.856016 |
| 1 J = 1 W·s. Conversions used: 1 Wh = 3600 J; 1 kWh = 3,600,000 J; 1 BTU ≈ 1055.05585 J. | |||||
What is a Watt Seconds To Heat?
A watt-second (W·s) is a unit of energy that is exactly equal to one joule (J). In other words, multiplying power (watts) by time (seconds) gives the total energy supplied. While that energy can be used for heating, it is not inherently “heat” unless the energy is actually transferred as heat to a material (and real systems may have losses). If you want the energy needed to raise a material’s temperature, you must also know the mass, specific heat, and temperature change (for example, Q = m·c·ΔT), and optionally an efficiency.
How to Calculate Watt Seconds To Heat?
The following steps outline how to calculate the watt-seconds (energy) using the formula WSH = P * t.
- First, determine the (average) power in watts (P).
- Next, determine the time in seconds (t).
- Next, use the formula from above: WSH = P * t.
- Finally, calculate the watt-seconds (WSH), which is energy in joules.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem:
Use the following variables as an example problem to test your knowledge.
power in watts (P) = 50
time in seconds (t) = 10
