When to use this calculator
The wattage printed on an appliance may describe a maximum rather than its typical continuous consumption.
Explore the electricity use & bills calculators for other questions in this topic. For a related calculation, use the Appliance Energy Calculator: Estimate electricity consumption from appliance power and operating hours.
PUTTING IT INTO PRACTICE
Appliance Annual Cost: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Power (W) | 100 |
| Hours per day | 5 |
| Days per year (integer) | 365 |
| Price per kWh | 0.3 |
| Result | 54.75 per year |
- Check the input labels and enter the example values above.
- Apply the relationship: Annual cost = watts/1000 × hours × days × unit rate.
- The result is 54.75 per year, rounded for display.
How to interpret your result
Uses constant operating power. Devices that cycle on and off require an average-power or runtime adjustment.
Watts describe power and kilowatt-hours describe energy. Fixed charges do not vary directly with consumption. Devices with thermostats or cycling loads need measured average energy or realistic operating time.
Frequently asked questions
Can I multiply rated watts by 24 hours for every appliance?
Only if it actually draws that power continuously. Cycling and variable-power appliances require a better average-use estimate.
When is the appliance annual cost calculator useful?
The wattage printed on an appliance may describe a maximum rather than its typical continuous consumption.
How do I use the appliance annual cost calculator?
Enter power (w), hours per day, days per year (integer), price per kwh. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Annual cost = watts/1000 × hours × days × unit rate.
What should I check before using the result?
Uses constant operating power. Devices that cycle on and off require an average-power or runtime adjustment.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Calculators Map editorial process · Updated · Methods and limitations