Electricity Cost Calculator
Use this electricity cost calculator to pinpoint what each appliance adds to your power bill. Enter your hardware wattage, run time, and local utility rate per kWh to calculate your true daily and monthly usage immediately.
What is a Kilowatt-Hour (kWh)?
A kilowatt-hour (kWh) is a unit of energy measuring 1,000 watts of electrical power consumed continuously over one hour. Utility providers use kWh as the standard billing unit on your monthly statement to charge for your total energy consumption.
Finding how much does it cost to run an appliance per day or month comes down to this single metric. For example, running a 100W light fixture for 10 hours draws 1,000 watt-hours, or exactly 1 kWh.
How to Calculate Electricity Bill From Watts
To figure out the electricity cost calculator per kWh value for any device, convert its base power draw into kilowatt-hours and multiply that by your local electricity rate:
Formula: (Watts × Hours ÷ 1000) × Rate per kWh
Monthly Cost ($) = Daily kWh × 30 × Utility Rate ($/kWh)Quick Benchmark: Wondering about the cost to run 1000 watts for 24 hours? At an average rate of $0.16 per kWh, a 1,000W space heater running full-time uses 24 kWh daily: 24 kWh × $0.16 = $3.84 per day ($115.20/month).
Step-by-Step Optimization Guide
1. Check Wattage (W): Locate the nameplate sticker on your device. If it only states voltage and amperage (V, A), multiply them to calculate watts (Volts × Amps = Watts). A 120V appliance drawing 2A uses 240W.
2. Estimate Daily Runtime: Log active operating hours per day. Keep in mind that duty-cycle machines like air conditioners and refrigerators cycle on and off rather than drawing continuous peak wattage.
3. Check Your Utility Rate: Grab your latest power bill and check your electricity rate per kWh, including baseline supply and delivery charges.
4. Cut Idle Phantom Draw: Standby electronics—like game consoles, TVs, and microwave clocks—draw background wattage around the clock. Put these items on smart power strips to immediately eliminate unnecessary monthly usage.
Frequently Asked Questions
How do I calculate my electricity cost?
Multiply the appliance wattage by your daily run hours, divide by 1,000 to get daily kilowatt-hours (kWh), and multiply by your utility rate per kWh. The formula is: (Watts × Hours ÷ 1000) × Rate per kWh.
How much electricity does a device use per hour?
A device consumes its exact rated wattage in watt-hours for every hour of runtime. To get kilowatt-hours, divide the wattage by 1,000. A 150-watt TV running for 1 hour consumes 0.15 kWh.
What is the average cost per kWh in the US?
The national average residential electricity rate in the US is roughly $0.16 to $0.18 per kWh. Rates vary by region, ranging from $0.11/kWh in states like Washington and Idaho up to $0.30–$0.45/kWh in California, Hawaii, and New England.
How do you convert watts to kWh?
Multiply total wattage by hours of operation, then divide by 1,000. For example, a 500W space heater running for 4 hours uses: (500 × 4) ÷ 1,000 = 2 kWh.
Appliance Energy Tracker
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Monthly Power draw
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