How to Improve Your Car's Fuel Economy: 10 Tips That Actually Work

With fuel prices in the UK averaging around 140p per litre for petrol and 145p for diesel in early 2026, getting the most from every tank is more important than ever. The good news is that you do not need to buy a new car to cut your fuel bills — small changes to how you drive and maintain your current car can make a significant difference.

The Energy Saving Trust estimates that adopting efficient driving habits can improve your fuel economy by 15–30%. On an average UK annual mileage of around 7,400 miles, that could save you £200–£500 a year depending on your car.

Here are 10 proven tips, ranked by their real-world impact on your fuel economy.

1. Drive Smoothly and Anticipate Traffic

Potential MPG improvement: 15–30%

This is by far the most impactful change you can make. Harsh acceleration and late braking are the biggest fuel wasters. Every time you accelerate aggressively, your engine consumes significantly more fuel than it needs to.

The key is anticipation. Look well ahead, read the traffic, and adjust your speed gradually. If you can see a red traffic light 200 metres ahead, lift off the accelerator early rather than driving up to it and braking. In a modern fuel-injected car, lifting off the accelerator in gear uses zero fuel — the engine cuts fuel delivery entirely during engine braking.

2. Check Your Tyre Pressures Monthly

Potential MPG improvement: 2–3%

Underinflated tyres create more rolling resistance, which means your engine has to work harder to maintain speed. Tyres that are just 10 psi below the recommended pressure can increase fuel consumption by around 2–3%.

Check your pressures at least once a month when the tyres are cold. The correct pressures are listed on a sticker inside the driver's door frame or in your owner's manual. Most UK petrol stations offer free air — there is no excuse not to check.

3. Remove Unnecessary Weight

Potential MPG improvement: 1–2% per 50 kg

Every extra kilogram your car carries requires more fuel to accelerate. Clear out the boot and remove anything you do not need for your journey. Roof boxes, bike racks, and roof bars should be removed when not in use — even an empty roof rack adds aerodynamic drag that can increase fuel consumption by around 5% at motorway speeds.

4. Use the Right Engine Oil

Potential MPG improvement: 1–2%

Using the manufacturer-recommended engine oil grade ensures your engine runs as efficiently as possible. The wrong viscosity oil increases internal friction, which wastes fuel. Check your owner's manual for the correct specification — it will typically specify something like 5W-30 or 0W-20.

5. Plan Your Journeys and Combine Trips

Potential MPG improvement: varies

A cold engine uses significantly more fuel than a warm one. Several short trips from a cold start will use more fuel in total than one longer trip covering the same distance. Combine your errands into a single round trip where possible.

Using a sat nav or checking traffic apps before you set off can also help you avoid congested routes. Sitting in stop-start traffic is one of the worst scenarios for fuel economy.

6. Use Cruise Control on Flat Roads

Potential MPG improvement: 3–5% on motorways

Maintaining a constant speed is more efficient than repeatedly speeding up and slowing down. Cruise control is excellent on flat motorways and dual carriageways. However, on hilly roads it can actually increase fuel consumption because it accelerates hard to maintain speed on inclines. Use it selectively.

7. Reduce Air Conditioning Use

Potential MPG improvement: 5–10%

Air conditioning puts an extra load on your engine. At low speeds (under 40 mph), opening the windows is more fuel-efficient. At higher speeds, the aerodynamic drag from open windows outweighs the AC load, so close the windows and use the air conditioning instead.

In cooler weather, use the ventilation system without the AC compressor engaged. Most cars have a separate AC button that you can switch off while still using the fan and heating.

8. Keep Up with Servicing

Potential MPG improvement: 2–4%

A well-maintained engine runs more efficiently. Dirty air filters, worn spark plugs, and old engine oil all reduce your car's efficiency. Following the manufacturer's service schedule ensures everything is in optimal condition. A clogged air filter alone can increase fuel consumption by up to 10% in older cars.

9. Avoid Idling

Potential MPG improvement: varies

If you are stationary for more than about 30 seconds (not in traffic), switch off your engine. Modern engines do not need to warm up by idling — the most efficient way to warm a cold engine is to drive it gently. Many newer cars have stop-start systems that do this automatically, but if yours does not, do it manually when safe to do so.

10. Slow Down on the Motorway

Potential MPG improvement: 10–20%

Aerodynamic drag increases exponentially with speed. Driving at 70 mph uses roughly 9% more fuel than driving at 60 mph, and driving at 80 mph uses around 25% more than 70 mph. If you are not in a rush, dropping your motorway cruising speed from 70 to 60 mph can make a noticeable difference to your fuel bill.

Final Thoughts

You do not need to adopt all 10 tips at once. Start with smooth driving — it is free and has the biggest impact. Then work through the maintenance items and gradually build better habits. Most UK drivers who focus on fuel-efficient driving report saving £200–£500 per year without making any changes to their car.

If you are consistently getting poor fuel economy despite these tips, it may be worth having your car checked by a mechanic. Issues like a faulty oxygen sensor, dragging brakes, or a misfire can significantly reduce your MPG.