Your gas bill usually includes a daily supply charge and a usage charge based on how much gas you consume, often measured in megajoules (MJ). Costs can vary with your retailer, tariff, location, billing period, household size and use of gas appliances such as heaters, hot-water systems and cooktops. Check the bill for your usage, rates and any concessions, then compare available plans using the Australian Government’s Energy Made Easy service. If the bill seems unusually high, ask your retailer to explain it and check for appliance or meter issues.