Understanding your vehicle's fuel efficiency helps you budget for gas costs, compare vehicles before buying, and track changes in efficiency over time that might indicate maintenance issues. This fuel mileage calculator computes your miles per gallon (or equivalent fuel efficiency metric) based on the distance traveled and fuel consumed, and can also estimate fuel costs for trips based on your vehicle's efficiency and current fuel prices. It's useful for comparing different vehicles' running costs, planning road trip budgets, or simply tracking your car's performance over time. Regular tracking can also help you notice if your fuel efficiency drops, which might indicate a maintenance need.