WattMath

Electricity Bill Estimator

Calculate your monthly electricity bill based on your appliances and usage patterns. Supports both flat-rate and tiered pricing structures.

Rate Structure

Fixed monthly fee

US average: $0.12/kWh

Your Appliances

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Common appliance wattages
Refrigerator150W
Air Conditioner (Window)1000W
Central AC3500W
Space Heater1500W
TV (LED 50")100W
TV (Older LCD)200W
Desktop Computer200W
Laptop50W
Gaming Console150W
Washing Machine500W
Dryer (Electric)3000W
Dishwasher1800W
Microwave1000W
Electric Oven2500W
Coffee Maker1000W
Toaster1200W
Hair Dryer1500W
LED Light Bulb10W
CFL Light Bulb15W
Incandescent Bulb60W
Ceiling Fan75W
Electric Water Heater4500W
Pool Pump1500W
EV Charger (Level 2)7200W

Electricity Rates

Understanding your rate structure is key to managing electricity costs. The average US household uses ~900 kWh/month at $0.12/kWh, but rates vary widely by region.

  • Flat rate: Same price per kWh
  • Tiered: Price increases with usage
  • TOU: Price varies by time of day

How to Use

  1. Set your rate structure (flat or tiered) from your utility bill
  2. Add your appliances with their wattage and daily usage hours
  3. Use the reference guide for common appliance wattages
  4. Click Calculate to see your estimated monthly bill

FAQ

How do I find my electricity rate?

Check your electricity bill for the rate per kWh. Look for "energy charge" or "usage charge." If you see multiple tiers, enable tiered rates and enter each tier's rate and threshold.

What uses the most electricity?

Heating and cooling typically account for 40-50% of home energy use. Electric water heaters, dryers, and EV chargers are also high consumers. Refrigerators use moderate power but run 24/7.

Why is my estimate different from my bill?

Bills may include additional fees (fuel adjustment, delivery charges, taxes) not captured here. Also, actual usage varies with seasons, occupancy, and appliance age. Use this as a baseline estimate.