How to Save Money on Gas: What Actually Works

To save money on gas, drive more smoothly, ease off the highway speed, keep your tires properly inflated and drive fewer miles; these habits matter far more than where you fill up. Learning how to save money on gas is mostly about the gallons you burn, because you control those every day, while the price per gallon is largely set for you.

The figures below come from FuelEconomy.gov, the US Department of Energy and EPA's official fuel economy site, and from the Federal Trade Commission. They apply to conventional gas cars; hybrids and electric vehicles behave differently. Outside the US, the same physics applies to petrol and diesel cars, even though you'll measure in liters and kilometers.

What actually saves the most money on gas?

Driving style and speed have the largest effect, followed by fewer miles, then maintenance. Here's how the main tactics compare, using FuelEconomy.gov's estimates.

Small percentages add up because you buy gas every week. The same principle, fix the biggest repeated costs first, runs through our step-by-step method to save money every month.

Example (hypothetical): you drive 12,000 miles a year in a car that gets 25 mpg, so you buy about 480 gallons. At an assumed $3.50 a gallon, that's $1,680 a year. Improving your real-world mileage by 10% would save about $168. Plug in your own mileage and local price; the per-gallon figure here is only an assumption.

How does driving style affect gas mileage?

Speeding, hard acceleration and hard braking waste the most gas. FuelEconomy.gov says aggressive driving can lower gas mileage by roughly 15% to 30% at highway speeds and 10% to 40% in stop-and-go traffic.

Habits that help:

• Accelerate gently and look ahead. Coasting toward a red light instead of braking hard keeps the fuel you already paid for.
• Ease off the highway speed. Mileage usually drops quickly above 50 mph. FuelEconomy.gov estimates that each 5 mph over 50 is like paying an additional $0.31 per gallon, and that observing speed limits can improve fuel economy by 7% to 14%. Their per-gallon figure depends on the fuel price they assume, so treat it as a rough guide.
• Use cruise control on the highway to hold a steady speed, where it's safe to do so.
• Don't idle when parked. Idling can use a quarter to a half gallon of fuel per hour, and restarting a warm engine takes only about 10 seconds' worth of fuel. If you'll wait more than a short moment, and it's safe and legal, switch off.

Driver feedback displays and apps can help too; FuelEconomy.gov puts the average improvement around 3%, and about 10% for drivers who focus on saving fuel.

Does car maintenance save gas?

Yes, a little, and it also prevents more expensive repairs. The gains are smaller than driving habits but they are effortless once done.

• Tire pressure. Inflating tires to the right pressure can improve mileage by about 0.6% on average and up to 3% in some cases. Under-inflated tires cost about 0.2% for every 1 psi drop. Use the pressure on the sticker in the driver's door jamb or in your owner's manual, not the maximum on the tire sidewall.
• Motor oil. Using the manufacturer's recommended grade can improve fuel economy by 1% to 2%. Look for oil labeled "Energy Conserving."
• Air filters. On modern fuel-injected engines, replacing a clogged air filter improves acceleration but not fuel economy, according to FuelEconomy.gov. Change it when it's due, but don't expect it to cut your gas bill.
• Check engine light. Get it looked at promptly; some faults raise fuel use and emissions.

Regular maintenance is easier to afford when you set money aside for it monthly. Our guide on how to budget shows how to build small sinking funds for car costs.

Should you buy premium gas?

Only if your owner's manual requires it. The FTC says regular octane gas is recommended for most cars, and paying for a higher octane than your car needs doesn't buy better mileage.

Some engines do require or recommend premium, so check the manual or the label inside the fuel door. If the manual says "recommended" rather than "required," the manufacturer's guidance explains what to expect from regular. If the engine knocks on regular, have it checked rather than guessing.

How can you pay less per gallon?

Compare local prices, check whether stations charge more for cards, and use rewards only if you pay them off in full. These tactics trim the price; they don't change how much fuel you burn.

• Compare before you fill up. Gas price apps and websites show nearby prices. Driving far out of your way to save a few cents usually burns the savings.
• Check cash and card prices. Some stations post a lower cash price. Read the pump sign before you pay.
• Warehouse clubs and grocery fuel rewards can lower the price, but a club membership costs money each year. Do the math against how many gallons you buy.
• Gas rewards credit cards pay back a percentage of fuel spending. If you carry a balance, interest wipes out the reward quickly.
• Skip fuel-saving gadgets and additives. The FTC has warned that the EPA found very few such products provide any benefit, and that some can damage your engine or increase emissions.

How do you drive fewer miles?

Plan trips, share rides and replace the occasional drive with something cheaper. Fewer miles cut fuel, wear and maintenance all at once.

• Combine errands. FuelEconomy.gov notes that several short trips from a cold start can use twice as much fuel as one longer trip covering the same distance. Plan a single loop.
• Carpool or ride-share for regular commutes. FuelEconomy.gov says this can cut weekly fuel costs by up to half.
• Shift your schedule to avoid rush-hour stop-and-go traffic, if your employer allows it.
• Work from home on the days your job permits.
• Use transit, cycling or walking for short, predictable trips.
• Drive your most efficient vehicle if your household has more than one.

Do AC, open windows, roof racks and extra weight matter?

They matter, mostly at higher speeds and in heat. Small changes here are free.

• AC versus windows. In very hot conditions, AC use can reduce a conventional car's fuel economy by more than 25%, especially on short trips. FuelEconomy.gov suggests rolling the windows down at lower speeds and using the AC at highway speeds, where open windows add more drag.
• Roof cargo boxes. A roof box can reduce fuel economy by around 2% to 8% in city driving, 6% to 17% on the highway and 10% to 25% at Interstate speeds. Rear-mounted carriers cost much less. Take the box off when you don't need it.
• Extra weight. An extra 100 pounds in the car could reduce mileage by about 1%. Clear out sports gear, tools and anything else you don't need on a daily drive.

Next steps

This week, check your tire pressure against the door-jamb sticker, take off any roof box you aren't using, and try driving 5 mph slower on the highway for a full tank. Note your miles per gallon before and after so you see your own result.

Fuel is only one part of what a car costs. Our guide on how to save money on car insurance covers the next biggest bill, and our everyday money saving tips cover the rest of the household. For a routine that turns these savings into money that actually stays saved, follow our simple plan for how to save money. And if you'd like to earn more as well as spend less, see our guide to making money online.