Electricity Calculator
Calculate electricity costs, kilowatt-hours, voltage, current, and power consumption.
Frequently Asked Questions
How do I calculate my electricity bill?
To calculate electricity cost, use: Cost = (Watts ÷ 1000) × Hours × Rate per kWh. For example, a 1000-watt heater running 8 hours a day at $0.12 per kWh costs: (1000 ÷ 1000) × 8 × $0.12 = $0.96 per day, or about $28.80 per month. Check your electric bill for your local rate. US residential rates average around $0.12–0.16 per kWh, but they vary significantly by state and season, with some states like Hawaii charging much more.
What is the difference between watts and kilowatt-hours?
Watts (W) measure power — the rate of energy use at any given moment. Kilowatt-hours (kWh) measure energy — the total amount consumed over time. A 100-watt light bulb running for 10 hours uses 1 kilowatt-hour (1 kWh) of energy. Your electricity bill charges you for kWh consumed, not watts. Think of watts as speed and kWh as distance traveled — you need both the rate and the duration to know total energy use and therefore cost.
How can I reduce my electricity bill?
Key strategies to lower electricity costs include: switching to LED bulbs (use 75% less energy than incandescent), unplugging devices on standby ("vampire" loads can account for 10% of a bill), using a programmable thermostat, running appliances during off-peak hours when rates are lower, improving insulation, and upgrading to Energy Star-rated appliances. An energy audit from your utility company can pinpoint your largest consumption sources. Small behavioral changes, like shorter showers and turning off lights, also add up significantly over a month or year.