Electricity Bill Calculator
Calculate electricity cost for any appliance or device. Enter watts, daily usage hours, and your electricity rate to find daily, monthly, and annual cost.
US avg $0.13 · UK ~$0.28 · AU ~$0.25 · CA ~$0.11
Monthly Cost
$46.8
360 kWh/month
Daily Cost
$1.56
Annual Cost
$569.4
Daily kWh
12 kWh
Annual kWh
4380 kWh
CO₂/Year
1690.7 kg
Rate Used
$0.13/kWh
About the Electricity Bill Calculator
An electricity bill calculator estimates the monthly and annual cost of running any electrical device based on its power consumption in watts, daily usage hours, and your local electricity rate per kWh. Electricity costs are one of the largest and most controllable household expenses, yet most people have no idea what individual appliances actually cost to run. This calculator makes it concrete: enter the wattage of any device, how many hours per day you use it, and your electricity rate, and it instantly shows the daily, monthly, and annual cost — plus the CO₂ emissions impact. Whether you are evaluating the running cost of a new air conditioner, comparing the energy cost of an old refrigerator versus a new Energy Star model, or understanding the electricity impact of EV charging, this calculator gives you the exact numbers. It works for any voltage system (the calculation uses only watts and hours) and any electricity rate — from $0.08/kWh in parts of the US Southeast to $0.45/kWh in Hawaii or $0.35/kWh in parts of Europe. Electricity rates are shown for the US, UK, Canada, and Australia as reference points.
Formula
kWh/day = (W / 1000) × hours | Monthly cost = kWh/day × 30 × rate | Annual CO₂ = kWh/year × 0.386 kg/kWh (US avg)
How It Works
kWh per day = (Watts / 1,000) × Hours per day. Monthly kWh = kWh per day × 30. Annual kWh = kWh per day × 365. Cost = kWh × rate per kWh. CO₂ = kWh × CO₂ intensity (kg/kWh). Example 1 (air conditioner): 2,000W AC running 10 hours/day at $0.13/kWh. kWh/day = (2,000/1,000) × 10 = 20 kWh. Monthly = 20 × 30 = 600 kWh. Monthly cost = 600 × $0.13 = $78. Annual = 7,300 kWh, $949/year. Example 2 (EV charging): 7,200W Level 2 charger running 3 hours/day at $0.13/kWh. kWh/day = 7.2 × 3 = 21.6 kWh. Monthly = 648 kWh. Cost = $84.24/month. Example 3 (comparison): old refrigerator 250W × 24h = 6 kWh/day = $28.47/month vs new Energy Star at 100W = $11.39/month — $204/year savings.
Tips & Best Practices
- ✓Air conditioning dominates summer electricity bills: a 3.5 kW (12,000 BTU) window AC running 8 hours/day for 90 summer days uses 2,520 kWh — approximately 25% of a typical US home's annual consumption in one appliance for one season.
- ✓Refrigerator replacement ROI: an old 1990s-era refrigerator may draw 800-1,200W; a modern Energy Star model draws 100-150W. The 1,000W difference running 24/7/365 = 8,760 kWh/year savings × $0.13 = $1,138/year saved. A new refrigerator pays for itself in 1-3 years.
- ✓Electric water heating: a 4,500W water heater running 3 hours/day uses 13.5 kWh/day = $0.64/day = $234/year at US average rates. Heat pump water heaters use 60-70% less energy — payback on the premium price is typically 3-5 years.
- ✓Standby power audit: devices in standby mode collectively waste 5-10% of home electricity. A cable box at 20W standby × 24h = 0.48 kWh/day = $22.78/year running continuously. Smart power strips that cut standby power can save $50-100/year in a typical home.
Who Uses This Calculator
Homeowners comparing the running cost of old versus new appliances before purchasing. Renters estimating monthly electricity costs before signing a lease in a new unit. EV owners calculating the monthly electricity cost increase from daily charging. Homebuilders comparing the lifetime operating cost of different HVAC system sizes. Energy advisors helping clients identify the highest-consumption appliances for targeted replacement.
Optimised for: USA · UK · Canada · Australia · Calculations run in your browser · No data stored
Frequently Asked Questions
How is electricity cost calculated?
Cost = (Watts / 1000) × Hours × Days × Rate per kWh. Example: 1,500W air conditioner running 8 hours/day for 30 days at $0.13/kWh: (1500/1000) × 8 × 30 × $0.13 = $46.80/month.
What is the average electricity rate in the USA?
The US average is approximately $0.13/kWh as of 2025, but varies widely: Hawaii ($0.39), California ($0.25), Louisiana ($0.10). Check your utility bill for your specific rate, which may include tiered pricing.
How much does it cost to run a refrigerator per month?
A typical refrigerator uses 100-200W continuously: (150W/1000) × 24h × 30 days × $0.13 = $14.04/month. New Energy Star refrigerators use as little as 50-100W, while older models may use 200-400W.
What is the most expensive appliance to run?
Electric water heaters (4,000-5,500W), central air conditioning (2,000-5,000W), electric dryers (5,000-6,000W), and electric ovens (2,000-5,000W) are the highest consumers. EV charging (7,200-11,500W) is significant for daily drivers.
How does CO₂ relate to electricity consumption?
The US average is approximately 0.386 kg CO₂ per kWh (EPA). A home using 900 kWh/month generates 347 kg (765 lbs) of CO₂ equivalent monthly. This varies by grid region: coal-heavy areas can reach 0.8 kg/kWh; hydro-heavy regions 0.05 kg/kWh.