A gas bill usually includes a daily supply charge, usage charges based on the gas you consumed, and GST. Check the billing period, meter readings and whether the reading is actual or estimated, as an estimate may be adjusted later. Your usage may be shown in megajoules (MJ), with rates varying according to your plan and location. Bills can also include discounts, concessions, fees or credits. If anything looks incorrect, contact your retailer and compare the bill with your contract or the information on the Energy Made Easy website.