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Folds the kilowatt conversion and the pricing into a single expression, useful when only the final figure matters.
The Formula
Cost = watts x hours x rate / 1000
Folds the kilowatt conversion and the pricing into a single expression, useful when only the final figure matters.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| W | Power rating in watts | watts | The same rating as before; the division by 1000 is now inside the expression. |
| rate | Price per kilowatt-hour | currency per kilowatt-hour | The rate must be per kWh; a price per MWh would need an extra factor of 1000. |
| Cost | Total cost for the run | currency | One number, with no intermediate energy figure kept. |
What Each Symbol Means
Wwatts
Power rating in watts
The same rating as before; the division by 1000 is now inside the expression.
ratecurrency per kilowatt-hour
Price per kilowatt-hour
The rate must be per kWh; a price per MWh would need an extra factor of 1000.
Costcurrency
Total cost for the run
One number, with no intermediate energy figure kept.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate electricity cost page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Electricity Cost, filed under Everyday Life. Every number the guide produces comes from substituting into this one line.