Energy Consumption Calculator
Audit household energy use by adding up appliance loads and running hours.
Please note: An estimate based on the figures you entered. Real-world results vary with conditions this calculation cannot see, so treat it as a starting point rather than a final answer.
What the Energy Consumption Calculator does
A household energy audit multiplies each appliance wattage by its daily running hours and quantity. Sorting the results by consumption almost always reveals that a small number of loads dominate the bill, which is where efficiency spending should go first.
Formula
Daily kWh per appliance = Watts × Quantity × Hours ÷ 1,000Total daily = Sum across all appliancesAnnual cost = Daily kWh × 365 × Rate
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Appliance wattages | text | Yes | One value per appliance. |
| Hours used per day | text | Yes | One value per appliance, in the same order. |
| Quantity of each | text | Optional | Optional — defaults to one of each. |
| Electricity rate per kWh | selected currency | Yes | Accepts more than 0. |
| Currency | one of 10 options | Optional | — |
How to use it
- Choose Currency.
- Enter Appliance wattages, Hours used per day and Electricity rate per kWh.
- Optionally add Quantity of each.
- Select Calculate.
Worked example
A fridge at 150 W for 24 h, a 2,000 W heater for 2 h, a 500 W washer for 1 h, eight 60 W lamps for 6 h.
- Watts
- 150, 2000, 500, 60
- Hours
- 24, 2, 1, 6
- Quantities
- 1, 1, 1, 8
3.6 + 4.0 + 0.5 + 2.88 = 10.98 kWh a day, about 4,008 kWh a year costing $1,122.
Frequently asked questions
Where do I find appliance wattages?
On the rating plate, usually on the back or underside. If only voltage and current are shown, multiply them — 230 V × 8 A is 1,840 W.
Why is my calculated total lower than my bill?
Standby loads, forgotten appliances and heating or hot water are easy to miss. Compare against a real meter reading and add the difference as a baseline load.