Electricity Usage Calculator

Track every appliance's electricity use. Enter watts and hours per day — get your total kWh and annual electricity cost.

ApplianceWattsHrs/daykWh/day
3.60
0.50
0.40
0.48
1.00
6.00
$/kWh
Total electricity usage
4,373 kWh/year
Daily usage11.98 kWh/day
Monthly usage359 kWh/month
Daily cost$1.80
Monthly cost$53.91
Annual cost$655.91
Top consumerAir conditioner
BY APPLIANCE (kWh/day)
Air conditioner6.00 kWh (50%)
Refrigerator3.60 kWh (30%)
LED lighting (home)1.00 kWh (8%)
Washing machine0.50 kWh (4%)
Laptop0.48 kWh (4%)
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How to Use This Calculator

Enter each appliance with watts and hours

The calculator starts with a typical home load — refrigerator, washing machine, TV, laptop, lighting, and air conditioner. Edit any row directly: change the appliance name, its wattage in watts, and how many hours per day it runs. Find wattage on the device nameplate, plug-in energy monitor, or the manufacturer specs. Hours per day is your average daily run time, not the hours the device is plugged in.

Add appliances from the preset list

Use the "+ Add appliance" dropdown to add common devices with pre-filled wattages. Adjust the hours to match your actual usage. For devices that cycle on and off (like refrigerators), the preset watt value already represents average draw — not peak startup watts.

Set your electricity rate

Enter your electricity rate in $/kWh. Find this on your utility bill under "energy charge" or "rate per kWh." The US average is ~$0.15/kWh but ranges from $0.09 (Louisiana) to $0.35+ (Hawaii, California, parts of New England).

The Formula

Daily kWh = ∑(Appliance watts × Hours per day) ÷ 1000 Monthly kWh = Daily kWh × 30 Annual kWh = Daily kWh × 365 Annual cost = Annual kWh × electricity rate ($/kWh)

Each appliance contributes its wattage multiplied by the hours it runs per day, divided by 1,000 to convert watt-hours to kilowatt-hours. The total daily kWh is the sum across all appliances. Monthly and annual figures are simple multiplications.

Example

Average US home — default appliances, $0.15/kWh

With the default appliance list (refrigerator 24 hrs, washing machine 1 hr, TV 5 hrs, laptop 8 hrs, LED lighting 5 hrs, AC 4 hrs) at $0.15/kWh:

Refrigerator3.6 kWh/day
Air conditioner6.0 kWh/day
All others~3.0 kWh/day
Total daily~12.6 kWh/day
Monthly~378 kWh
Annual cost~$690/year

This is below the US average of ~10,500 kWh/year because the AC only runs 4 hrs/day. Homes in hot climates running AC 10+ hours/day will see significantly higher totals.

FAQ

Look for a label on the appliance itself — usually on the back, bottom, or inside the door. It will say "watts" or "W" or list both voltage and amps (watts = volts × amps). If you can only find amps and volts, multiply them together. For the most accurate reading, use a smart plug or kill-a-watt meter to measure actual consumption. Manufacturer websites also list power consumption in spec sheets.
The US Energy Information Administration (EIA) reports average US household consumption at about 10,500 kWh/year (about 875 kWh/month) as of 2022. Louisiana has the highest average (~1,300 kWh/month) due to heavy AC and electric heating use. Hawaii and California have lower usage but much higher rates, so bills are still high. All-electric homes (with electric heating, water heaters, and EV charging) commonly use 15,000–25,000 kWh/year.
Take your annual kWh from this calculator and divide by your expected annual solar production per panel. A 400W panel in an average US location (4.5 peak sun hours) produces about 400 × 4.5 × 365 × 0.86 ÷ 1000 ≈ 565 kWh/year. Divide your annual usage by 565 to get approximate panel count. Use our Solar Panel Calculator for a precise calculation.
Several reasons: (1) You may have missed appliances — phantom loads from standby devices can add 5–10% of total usage. (2) Hours/day estimates may be off — for appliances that cycle (refrigerators, HVAC), use duty cycle × 24 hours. (3) Electric water heaters and HVAC systems are the largest variables. (4) Utility bills also include demand charges, taxes, and fees beyond the energy charge. Use our Standby Power Calculator to add hidden phantom loads.

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