Appliance Energy Calculator
Compare the running cost of two appliances side by side to see which one costs more to operate.
Result
Enter your numbers to see the estimate.
Appliance A
Appliance B
How this calculator works
Deciding between two appliances — an old fridge versus a new energy-efficient one, or a space heater versus a heat pump — often comes down to running cost. This calculator lets you enter the wattage, daily usage and electricity rate for two appliances at once and compares their daily, monthly and annual costs side by side.
The formula behind each estimate is the same as our electricity cost calculator: kWh = watts ÷ 1000 × hours, and cost = kWh × your electricity rate. Comparing two appliances this way is especially useful when weighing an upfront purchase (like a more efficient appliance) against its long-term running cost savings.
Keep in mind that real-world usage patterns vary — an appliance that cycles on and off (like a fridge or AC) doesn't run at full wattage continuously, so treat this as a reasonable estimate for planning, not a lab-grade measurement.
Example: Comparing a 150-watt fridge running 8 hours/day against a 400-watt older fridge running 8 hours/day, at $0.15/kWh, shows a monthly cost difference of about $9.
How it works
Enter your measurements or costs
Fill in the room size, materials or costs for your project. No sign-up required.
Adjust the settings
Choose your units, waste percentage and any project-specific options.
Get your estimate instantly
See your results calculated instantly, right in your browser.
Frequently asked questions
How do I compare two appliances' running costs?
Enter the wattage, hours per day and days per month for each appliance, plus your electricity rate. The calculator shows daily, monthly and annual cost for both, side by side.
Is it worth replacing an old appliance to save on electricity?
This calculator can help you see the potential monthly and annual savings, which you can weigh against the cost of a replacement appliance — but it doesn't factor in the purchase price itself.
Do appliances run at full wattage all the time?
No, many appliances like fridges and air conditioners cycle on and off rather than running continuously at full wattage. Use your appliance's estimated average daily runtime for the most realistic result.
How accurate is this comparison?
It's a solid planning estimate based on the wattage and usage hours you enter. Actual costs depend on your appliance's efficiency, cycling behavior and your utility's exact rate structure.
Do I need to create an account to compare appliances?
No. This tool works instantly with no sign-up, login or payment required.