Appliance Energy Consumption Calculator

Q: How do I calculate appliance energy consumption?

Energy (kWh) = Watts ÷ 1000 × Hours used. For example, a 1,200W microwave used 0.5 hours/day: 1.2 kW × 0.5h = 0.6 kWh/day = 18 kWh/month.

Q: What appliance uses the most electricity?

Electric water heaters, air conditioners, and electric dryers are typically the top energy consumers in homes. A central AC unit can use 3,000–5,000W, running for many hours daily in summer. EV charging can also add significant consumption.

Q: How accurate are nameplate wattage ratings?

Nameplate watts is the maximum rated power, not average consumption. Variable-speed appliances (inverter ACs, modern fridges) draw much less than rated at typical operating conditions. For the most accurate figures, use a plug-in energy monitor for a few days of real measurement.

Calculate how much energy and money each of your appliances costs to run. Add multiple appliances, enter wattage and daily hours, and see individual and total costs.

Add Your Appliances

Currency

Electricity Rate (per kWh)

Energy Summary

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Daily Usage (kWh)

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Monthly Usage (kWh)

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Annual Usage (kWh)

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Annual Cost

Formula

kWh/day = (Watts × Hours) ÷ 1000
Monthly kWh = kWh/day × 30
Annual kWh = kWh/day × 365
Annual Cost = Annual kWh × Rate

Common Appliance Power Consumption

Appliance	Typical Watts	Cost at $0.15/kWh (1hr)
Air conditioner (2.5 kW split)	800–1,500	$0.12–$0.23
Electric water heater	2,000–4,000	$0.30–$0.60
Electric oven	1,500–2,500	$0.23–$0.38
Tumble dryer	2,000–3,000	$0.30–$0.45
Washing machine	400–1,200	$0.06–$0.18
Refrigerator (modern)	100–200	$0.015–$0.03
Microwave	800–1,500	$0.12–$0.23
LED TV 55"	70–120	$0.01–$0.02
LED bulb	8–15	<$0.01
Laptop	30–80	$0.005–$0.012

Frequently Asked Questions

How do I calculate appliance energy consumption?

kWh = Watts ÷ 1000 × Hours. Multiply daily kWh by 30 for monthly, 365 for annual. Multiply by your electricity rate for cost. Example: a 300W refrigerator running effectively 8 hours/day: 0.3 × 8 = 2.4 kWh/day = 72 kWh/month × $0.15 = $10.80/month.

What appliance uses the most electricity?

In most homes: (1) HVAC (heating and cooling), (2) electric water heater, (3) clothes dryer, (4) refrigerator, (5) lighting. In homes with EVs, the charger often becomes the second-largest consumer after HVAC. Water heating alone can account for 15–20% of a home's energy use.

How accurate are nameplate wattage ratings?

The nameplate shows maximum rated power. Modern inverter air conditioners and refrigerators use variable-speed compressors that run at a fraction of rated power most of the time. An inverter AC rated at 1,500W might average only 600–800W over a day. For accuracy, measure with a plug-in energy monitor rather than relying on nameplate ratings.