An appliance’s wattage is printed on its label or in the manual. Multiplying by how long it runs each day gives the energy it uses. Fridges cycle on and off, so their average draw is much lower than the label power – use about a third of the rated watts over 24 hours.
How to use the Appliance Wattage Calculator
- Appliance 1 (TV) – watts
- Appliance 1 – hours per day
- Appliance 2 (Refrigerator (average)) – watts
- Appliance 2 – hours per day
- Appliance 3 (Washing machine) – watts
- Appliance 3 – hours per day
- Appliance 4 (Laptop) – watts
- Appliance 4 – hours per day
- Appliance 5 (Lights) – watts
- Appliance 5 – hours per day
- Electricity price
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the wattage and daily hours of up to five appliances (leave unused rows at zero) and your electricity price.
Tips
- Use the figures from your own bills and product labels – prices and appliance ratings vary widely.
- Look at yearly totals: small daily costs add up and make it easier to compare options.
- Round quantities up to whole packs, rolls or bulbs when you shop.
- Re-check the numbers when prices change; most results scale directly with the unit price.
Common mistakes to avoid
- Confusing watts (power) with watt-hours or kilowatt-hours (energy).
- Comparing prices without bringing them to the same unit first.
- Ignoring one-off costs such as installation, delivery or replacement parts.
Inputs explained
| Field | What to enter |
|---|---|
| Appliance 1 (TV) – watts | Units: W, kW, hp |
| Appliance 1 – hours per day | A number |
| Appliance 2 (Refrigerator (average)) – watts | Units: W, kW, hp |
| Appliance 2 – hours per day | A number |
| Appliance 3 (Washing machine) – watts | Units: W, kW, hp |
| Appliance 3 – hours per day | A number |
| Appliance 4 (Laptop) – watts | Units: W, kW, hp |
| Appliance 4 – hours per day | A number |
| Appliance 5 (Lights) – watts | Units: W, kW, hp |
| Appliance 5 – hours per day | A number |
| Electricity price | Units: /kWh |
What each result means
- Energy per day = ([Appliance 1 (TV) – watts]×[Appliance 1 – hours per day] + [Appliance 2 (Refrigerator (average)) – watts]×[Appliance 2 – hours per day] + [Appliance 3 (Washing machine) – watts]×[Appliance 3 – hours per day] + [Appliance 4 (Laptop) – watts]×[Appliance 4 – hours per day] + [Appliance 5 (Lights) – watts]×[Appliance 5 – hours per day])÷1000
- Energy per month = [Energy per day]×30.44
- Cost per day = [Energy per day]×[Electricity price]
- Cost per month = [Energy per month]×[Electricity price]
- Cost per year = [Energy per day]×365.25×[Electricity price]
Example values
How the main result changes when Appliance 1 changes and everything else stays at the example values above:
| Appliance 1 (TV) – watts (W) | Cost per month |
|---|---|
| 50 | 12.13 |
| 75 | 12.61 |
| 100 | 13.1 |
| 125 | 13.59 |
| 150 | 14.08 |
| 200 | 15.05 |
Formula
Energy per appliance (kWh/day) = watts × hours per day × quantity ÷ 1,000Monthly = daily × 30.44; cost = kWh × priceWorked example
Inputs — Appliance 1 (TV) – watts: 100 W; Appliance 1 – hours per day: 4; Appliance 2 (Refrigerator (average)) – watts: 60 W; Appliance 2 – hours per day: 24; Appliance 3 (Washing machine) – watts: 500 W; Appliance 3 – hours per day: 0.5; Appliance 4 (Laptop) – watts: 50 W; Appliance 4 – hours per day: 6; Appliance 5 (Lights) – watts: 60 W; Appliance 5 – hours per day: 5; Electricity price: $0.16 /kWh.
Results — Energy per day = 2.69 kWh; Energy per month = 81.9 kWh; Cost per day = $0.43; Cost per month = $13.10; Cost per year = $157.20.
Frequently asked questions
How do I calculate appliance energy use?
Watts × hours ÷ 1,000 = kWh. A 100 W TV on for 4 hours uses 0.4 kWh a day.
Why is my fridge cheaper than its wattage suggests?
The compressor runs only part of the time, typically 30–40%.
What uses the most electricity at home?
Heating and cooling, water heating, dryers and old refrigerators.
What formula does the Appliance Wattage Calculator use?
Energy per appliance (kWh/day) = watts × hours per day × quantity ÷ 1,000.