Fuel Cost Calculator

How to Calculate Fuel Costs

Calculating fuel cost for any trip requires three basic pieces of information: the distance you plan to travel, your vehicle's fuel efficiency, and the current price of fuel. The formula is straightforward. For vehicles measured in miles per gallon (MPG), divide the total trip distance by your MPG rating to find the number of gallons needed, then multiply by the price per gallon. For example, a 300-mile trip in a car that gets 30 MPG requires 10 gallons. At $3.50 per gallon, the total fuel cost is $35.00.

If you use the metric system with liters per 100 kilometers (L/100km), the calculation works slightly differently. Multiply your distance in kilometers by the L/100km rating, then divide by 100 to get the total liters needed. Multiply that by the price per liter to find your total cost. A 500 km trip in a vehicle rated at 8 L/100km requires 40 liters of fuel. At $1.50 per liter, the total comes to $60.00.

Understanding Fuel Efficiency: MPG and L/100km

Fuel efficiency measures how far a vehicle can travel on a given amount of fuel. In the United States, this is expressed as miles per gallon (MPG), where a higher number means better efficiency. Most of the rest of the world uses liters per 100 kilometers (L/100km), where a lower number indicates better efficiency. To convert between these systems, divide 235.21 by the MPG value to get L/100km, or divide 235.21 by L/100km to get MPG.

Fuel efficiency varies significantly between vehicle types. Compact cars typically achieve 30 to 40 MPG (6 to 8 L/100km), while full-size SUVs may only manage 18 to 25 MPG (9 to 13 L/100km). Hybrid vehicles can reach 45 to 55 MPG (4 to 5 L/100km), and fully electric vehicles bypass fuel entirely, measuring efficiency in miles per kilowatt-hour. Your actual fuel efficiency depends on driving conditions, with highway driving generally being more efficient than city driving due to fewer stops and more consistent speeds.

Tips to Improve Your Fuel Economy

Small changes in driving habits can yield meaningful fuel savings over time. Maintaining a steady speed and using cruise control on highways can improve fuel economy by 10 to 15 percent. Aggressive driving behaviors like rapid acceleration and hard braking increase fuel consumption by as much as 33 percent on highways and 5 percent in city driving. Keeping your tires inflated to the recommended pressure improves efficiency by about 3 percent, since underinflated tires create more rolling resistance.

Vehicle maintenance also plays a critical role. A well-tuned engine, clean air filters, and fresh motor oil all contribute to optimal fuel efficiency. Removing excess weight from your vehicle helps as well, since every additional 100 pounds reduces fuel economy by approximately 1 percent. Reducing aerodynamic drag by removing roof racks when not in use and keeping windows closed at highway speeds can also make a noticeable difference. Planning your route to avoid traffic congestion and combining multiple short trips into one longer trip further reduces overall fuel consumption.

Gas Price Trends and What Affects Them

Fuel prices fluctuate based on a complex web of factors. Crude oil prices are the primary driver, accounting for roughly 50 to 60 percent of the retail gasoline price. Refining costs, distribution and marketing expenses, and federal and state taxes make up the remainder. Seasonal patterns also influence pricing, with gasoline typically becoming more expensive in summer due to increased travel demand and the switch to more expensive summer-blend formulations required to reduce smog. Geopolitical events, natural disasters affecting refinery operations, and changes in global oil production quotas by organizations like OPEC can cause sudden price spikes. Tracking these trends helps you plan your trips and budget your transportation costs more effectively, especially for long-distance road trips or daily commutes.