How to Improve Gas Mileage: 15 Proven, Measurable Tips

Gas prices rise and fall, but fuel efficiency is always in your control. The U.S. Department of Energy (DOE) and the Environmental Protection Agency (EPA) have spent decades researching exactly how much each driving habit, maintenance task, and vehicle choice affects fuel economy. The numbers are specific, actionable, and sometimes surprising.

This guide covers 15 proven strategies backed by DOE and EPA research. Each tip includes the approximate fuel economy gain you can realistically expect. Use our MPG Calculator to measure your baseline before and after making changes so you can see the real-world difference in your own vehicle.

Why Small Gains Add Up Fast

A 5% improvement might sound minor, but if you currently get 28 MPG and drive 15,000 miles per year, that improvement saves roughly 40 gallons of fuel annually. Stack several of these changes together and the savings become meaningful, both for your wallet and for reducing emissions.

1. Check Tire Pressure Monthly

Under-inflated tires are one of the most common and most overlooked fuel economy killers. The DOE estimates that you can improve gas mileage by about 0.2% for every 1 PSI drop in pressure you correct across all four tires. Tires typically lose 1 PSI per month and about 1 PSI for every 10-degree Fahrenheit drop in temperature. Check your tires monthly when they are cold, and inflate them to the pressure listed on the sticker inside your driver-side door jamb, not the maximum pressure stamped on the tire itself.

2. Drive at 55 to 65 MPH on the Highway

Speed is one of the biggest factors in fuel economy, and the relationship is not linear. According to DOE data, fuel economy typically decreases rapidly above 50 MPH. You can assume that each 5 MPH you drive over 50 MPH is like paying an additional $0.30 per gallon of gas (at average fuel prices). More specifically, every 10 MPH over 55 MPH costs you between 7% and 14% in fuel economy. Driving 75 MPH instead of 65 MPH can reduce your MPG by 15% or more, depending on your vehicle.

3. Use Cruise Control on Flat Highways

Maintaining a perfectly steady speed is something humans are not naturally good at. Most drivers unconsciously let their speed creep up and down by several miles per hour, which wastes fuel with every unnecessary acceleration. Cruise control eliminates this habit. The DOE notes that using cruise control on flat terrain can improve fuel economy by 7% to 14% compared to variable-speed driving. The benefit is smaller on hilly roads, where manual control and anticipating terrain changes is often more efficient.

4. Accelerate and Brake Smoothly

Aggressive driving is expensive. Rapid acceleration and hard braking can reduce your fuel economy by 15% to 30% in city driving and 10% to 40% on the highway, according to DOE and EPA findings. The physics are straightforward: every time you brake hard, you are converting kinetic energy into heat and throwing away the fuel that created that motion. Smooth, gradual acceleration and coasting to decelerate whenever traffic allows keeps more of your fuel working for you. Anticipating traffic signals and maintaining a safe following distance naturally encourages this calmer style of driving.

5. Remove Excess Weight from Your Vehicle

Your engine works harder to move more mass. The DOE estimates that an extra 100 pounds in your vehicle can reduce fuel economy by 1% to 2%, with the impact being proportionally greater for smaller, lighter vehicles. Many drivers carry unnecessary cargo in their trunk year-round: tools, sports equipment, bags of salt from winter, or other items accumulated over time. Clear out what you do not need. A clean trunk is a free efficiency upgrade.

6. Remove Roof Racks and Cargo Carriers When Not in Use

Aerodynamic drag increases with the square of your speed, which means the penalty for carrying empty roof racks grows steeply as you drive faster. The DOE has found that rooftop cargo boxes can reduce fuel economy by 2% to 8% in city driving, 6% to 17% on the highway, and as much as 10% to 25% at highway speeds when the box is large and boxy. Even an empty roof rack adds drag. If you use a roof rack or cargo carrier seasonally, remove it and store it when it is not needed.

7. Use the Recommended Motor Oil Grade

Using the wrong viscosity oil makes your engine work harder due to increased internal friction. The DOE notes that using the manufacturer’s recommended grade of motor oil can improve fuel economy by 1% to 2%. Additionally, switching from conventional oil to a full synthetic in an engine designed for it can further reduce friction and improve efficiency. Check your owner’s manual for the recommended oil viscosity, typically listed as something like 5W-30 or 0W-20, and stick with it.

8. Keep the Engine Properly Tuned

A well-maintained engine runs more efficiently and burns fuel more completely. The fuel economy benefit of a tune-up depends heavily on what is being fixed. Repairing a minor issue like spark plugs that are past their service life can improve MPG by around 4%, according to EPA estimates. Fixing a faulty oxygen sensor, however, can improve fuel economy by as much as 40% because a malfunctioning sensor causes the engine management system to inject too much fuel. If your check engine light is on, address it promptly because it is almost certainly costing you at the pump.

9. Replace a Clogged Air Filter

Modern fuel-injected engines use computer-controlled fuel injection systems that compensate for reduced airflow, so a clogged air filter rarely hurts fuel economy directly the way it once did in carbureted engines. However, a severely restricted air filter can reduce acceleration performance significantly, which may lead drivers to press the accelerator harder to compensate, indirectly wasting fuel. Replacing a clogged filter restores engine responsiveness. Check your owner’s manual for the recommended service interval, and inspect the filter annually if you drive in dusty conditions.

10. Plan Trips to Consolidate Errands

Cold engine starts are far less efficient than driving a warmed-up engine. When an engine is cold, it runs a richer fuel mixture, the catalytic converter has not reached operating temperature, and friction in the drivetrain is higher. The EPA notes that several short trips taken from a cold start can use twice as much fuel as one longer trip covering the same total distance when the engine starts warm. Planning your errands so you string them together in a single outing, rather than making multiple separate trips from home, significantly improves your overall fuel efficiency.

11. Avoid Excessive Idling

An idling engine gets exactly 0 MPG. The DOE estimates that idling burns between 0.5 and 0.9 gallons of fuel per hour, depending on engine size and whether accessories like air conditioning are running. If you are waiting in a pickup line, sitting in a drive-through, or parked waiting for someone, shutting off the engine after 60 seconds is almost always more fuel-efficient than letting it run. Modern engines do not require long warm-up periods, and the small amount of fuel used during a restart is far less than what is consumed by extended idling.

12. Use Air Conditioning Wisely

Air conditioning is a significant parasitic load on your engine. The DOE and EPA estimate that A/C use can increase fuel consumption by 5% to 25% depending on outside temperature, humidity, and driving conditions. At lower speeds in city traffic, A/C has a proportionally larger impact. At highway speeds above 45 to 50 MPH, however, rolling down your windows increases aerodynamic drag enough that A/C is actually comparable or more efficient. The practical advice: use windows and ventilation at lower speeds when outside air is tolerable, and use A/C more freely on the highway.

13. Check Wheel Alignment

Misaligned wheels create uneven tire contact with the road, which increases rolling resistance. While the exact MPG penalty varies by how far out of alignment the vehicle is, persistent drag from misalignment means your engine is constantly fighting resistance that should not be there. Poor alignment also causes uneven and accelerated tire wear, which will eventually require early tire replacement. If your vehicle pulls to one side, if the steering wheel is off-center on a straight road, or if you notice uneven tire wear, have the alignment checked. It is a relatively inexpensive service that protects both your fuel economy and your tires.

14. Park in Shade or a Garage

This tip works through two different mechanisms. First, high cabin temperatures caused by parking in direct sunlight mean you need more A/C to cool the interior when you start driving, increasing early-trip fuel consumption. Second, fuel evaporates from your tank more readily in high heat, contributing to evaporative emissions. Parking in shade, in a garage, or using a windshield sun shade keeps your cabin cooler and reduces the fuel your A/C needs to consume at startup. On hot days, leaving windows slightly cracked (when safe) also allows trapped hot air to escape.

15. Use the Correct Fuel Grade for Your Engine

Unless your vehicle specifically requires premium fuel, using it is pure waste. Premium fuel is formulated for high-compression or turbocharged engines that would otherwise knock or ping on regular fuel. In an engine designed to run on regular 87-octane fuel, filling up with 91 or 93 octane provides no performance benefit and no fuel economy improvement. You are simply paying more per gallon for fuel your engine cannot use more efficiently. Check your owner’s manual: if it says “premium recommended” rather than “premium required,” regular fuel is likely fine and the DOE confirms you will see no meaningful MPG difference.

Putting It All Together

No single tip on this list will transform your fuel economy overnight, but the combined effect of good habits, regular maintenance, and smart driving can add up to a 20% to 40% improvement compared to a poorly maintained vehicle driven aggressively. Start by tracking your current MPG with our MPG Calculator, then introduce changes one at a time and measure the difference. The DOE and EPA data cited above represents averages across vehicle types, so your specific gains may be higher or lower, but the direction is always the same: these habits put more miles in every gallon.