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Quick answer
What does the Standby power cost calculate?
What do always-on devices cost over a year? This calculator uses total standby power, standby hours per day, electricity price, and devices included to estimate always-on energy cost immediately in your browser.
With the values currently entered, the result is $42.05 — per year. It also shows energy / year, per device, and per month.
How to use the Standby power cost
- Replace the example values with your own numbers.
- Review the result and supporting figures as they update automatically.
- Check the formula and assumptions before using the estimate for a decision.
Inputs used
- Total standby power — entered in W
- Standby hours per day — entered in hrs
- Electricity price — entered in / kWh
- Devices included — entered in devices
Standby power cost formula
Watts ÷ 1000 × standby hours × 365 × electricity rate
Assumptions
- Standby draw stays constant.
- The entered watts cover all listed devices together.
Verify the inputs
Authoritative sources
These sources explain the definitions, factors, or rules behind this tool. Their geographic scope is shown because an official source for one country is not automatically valid somewhere else.
Sources do not endorse Calculum. Check the source date, scope, and your own documents before making a financial, tax, insurance, or reporting decision.
Practical guide
Standby power cost example and edge cases
What do always-on devices cost over a year? Let's use a concrete example, then look at the assumptions that can move the answer.
Example: A practical standby power cost scenario
For this example, use total standby power of 18 W, standby hours per day of 20 hrs, electricity price of 0.32 / kWh, and devices included of 6 devices. These are starting values, so replace them with numbers that match your situation.
- Total standby power
- 18 W
- Standby hours per day
- 20 hrs
- Electricity price
- 0.32 / kWh
- Devices included
- 6 devices
Calculated result$42.05per year
Start with per year. Then check energy / year, per device, and per month to understand what sits behind the main result.
Example results use the default display profile. The calculator above follows your selected country and units.
How to read the result
- Read the main result first. The supporting figures for energy / year, per device, and per month explain how the estimate is built.
- The method is Watts ÷ 1000 × standby hours × 365 × electricity rate. Keep the units consistent and use values from the same time period.
Edge cases worth checking
When total standby power is unusual
Standby draw stays constant. Double-check this input before relying on the result.
When devices included is uncertain
The entered watts cover all listed devices together. Run a lower and higher value to see a useful range.
What changes the result most
Total standby power
Change total standby power on its own first. This shows how strongly it affects the answer.
Standby hours per day
Change standby hours per day on its own first. This shows how strongly it affects the answer.
Electricity price
Use a current amount for electricity price. Include fees or recurring costs that belong in the same figure.
Try a different scenario
Small changes show whether the answer is stable or sensitive.
Total standby power: 10% lower
16 W$37.38per year
Total standby power: 10% higher
20 W$46.72per year
Standby hours per day: 10% higher
22 hrs$46.25per year
Common mistakes
Check total standby power
Standby draw stays constant. Make sure this matches the number you enter.
Keep devices included consistent
The entered watts cover all listed devices together. Use the same units and time period throughout the calculation.
Do not rely on one standby power cost scenario
Run a cautious case and an optimistic case. The range is often more useful than one exact-looking number.
Use this result well
What do always-on devices cost over a year?
Actual tariffs, weather, equipment behavior, and fixed charges can change the bill.