How do I calculate electricity cost for an appliance?

Multiply the appliance's wattage by the hours used per day, divide by 1,000 to get kilowatt-hours (kWh), then multiply by your electricity rate per kWh. For example, a 1,000W appliance run for 3 hours at $0.15/kWh costs 1,000 × 3 ÷ 1,000 × $0.15 = $0.45 per day.

What is phantom or standby power, and how much does it cost?

Phantom (or standby) power is electricity drawn by devices left plugged in but turned off or in standby mode. A typical home can lose 50-100 watts this way continuously, which can add up to $75-$150 per year depending on local electricity rates.

Does using appliances at night actually save money?

Only if your utility charges time-of-use rates with a cheaper off-peak price. Shifting usage like laundry, dishwashing, or EV charging to off-peak hours can save roughly 15-25% on those specific loads if your plan offers a meaningful rate difference.

How much does it cost to charge an EV at home?

A typical EV charger draws around 7,200 watts (Level 2). At $0.15/kWh, charging for 4 hours costs roughly 7.2 kW × 4 hours × $0.15 = $4.32, though the exact cost depends on the charger's power and your electricity rate.

What is a standing charge or service fee on an electric bill?

A standing charge (or service fee) is a fixed daily or monthly amount charged regardless of how much electricity you use, covering grid maintenance and connection costs. It's added on top of your usage-based charges, not included in them.

How do I find out how many watts my appliance uses?

Check the label on the appliance or its manual, which usually lists wattage directly. If only amps and voltage are listed, multiply them together (Watts = Amps × Volts) to estimate the wattage.

How accurate are online electricity cost calculators?

They provide a solid estimate based on rated wattage and typical usage hours, but actual costs can vary because many appliances cycle on and off (like refrigerators and AC units) rather than drawing constant power. A plug-in energy meter gives the most accurate real-world reading.

Electricity Cost Calculator – Appliance, Whole-Home & Peak Rates (Free)

🔌 Electricity Cost Calculator

Power (Watts)

Hours Used Per Day

Electricity Rate ($/kWh)

Quick-Add Common Appliances

Refrigerator Window AC Water Heater Space Heater LED Bulb EV Charger (Level 2)

🔌

Enter your details and click Calculate

Your electricity cost breakdown will appear here.

Calculating…

How It Works

The Electricity Cost Formula

Every mode above uses the same underlying formula — the difference is how many appliances and rates you're feeding into it.

Cost = Watts × Hours ÷ 1,000 × Rate

kWh = (Watts × Hours) ÷ 1,000

Then multiply the kWh figure by your electricity rate per kWh to get the cost.

Worked Example: Window AC, 8 Hours/Day at $0.15/kWh

1,000W × 8 hours ÷ 1,000 = 8 kWh/day

8 kWh × $0.15 = $1.20/day

✓ Over a 30-day month, that's about $36.00 — before any standing charge.

Hidden Cost

What Phantom (Standby) Power Actually Costs You

Devices left plugged in but "off" still draw power around the clock — this adds up more than most people expect.

Worked Example: 60W of Standby Draw, 24/7

60W × 24 hours ÷ 1,000 = 1.44 kWh/day

1.44 kWh × 365 days = 525.6 kWh/year

✓ At $0.15/kWh, that's about $79/year — spent on devices that were never actively being used.

A smart power strip that fully cuts power to entertainment centers, game consoles, and chargers when not in use is one of the highest-ROI purchases in home energy savings, often paying for itself within a few months.

Quick Reference

Typical Appliance Wattage & Monthly Cost

Estimated at $0.15/kWh with typical usage patterns — actual wattage varies by model and age.

Appliance	Typical Power	Typical Use	Est. Monthly Cost
LED bulb	10 W	8 hrs/day	~$0.36
Refrigerator	150 W (average)	24 hrs/day	~$16.20
Window AC unit	1,000 W	8 hrs/day	~$36.00
Central AC	3,500 W	6 hrs/day	~$94.50
Electric water heater	4,000 W	2 hrs/day	~$36.00
Space heater	1,500 W	4 hrs/day	~$27.00
EV home charger (Level 2)	7,200 W	4 hrs/day	~$129.60

FAQ

Electricity Cost Calculator — Frequently Asked Questions

Common questions about appliance costs, standby power, and time-of-use rates.