Electricity usage is measured in kilowatt-hours (kWh), which is the amount of energy used over time. Your meter records usage, while your bill usually shows the number of kWh used, the supply charge, usage rates, discounts and any credits or fees. Appliances with higher wattage, such as heaters, dryers and hot-water systems, generally use more electricity, especially when running for long periods. To understand your usage, compare bills across similar billing periods and check your retailer’s usage breakdown or smart-meter data if available. Your retailer can explain bill details and tariff options.