With 31 MPG combined, the 2018 Lexus GS 450h offers a mix of luxury, performance, and hybrid efficiency. It’s a mid-size luxury sedan that emphasizes a smooth, refined driving experience while also delivering respectable fuel economy, a feature appealing to buyers who value both luxury and less gas.

City and highway performance

The EPA estimates of 29 MPG in the city and 34 MPG on the highway show the GS 450h’s strengths. The hybrid powertrain allows electric-only operation at lower speeds, which contributes to its good city MPG. On the highway, the 3.5L V6 engine does more work, but the efficient Atkinson cycle design and the advanced eight-speed automatic transmission (AV-S8) help it maintain solid fuel economy. Frequent stop-and-go driving will benefit the hybrid system, keeping fuel economy closer to the official figures, while extended high-speed cruising might decrease mileage toward the regular GS 350’s numbers.

Annual fuel cost

The EPA estimates an annual fuel cost of $1,850 for the 2018 Lexus GS 450h. This is based on driving 15,000 miles per year, using national average fuel prices for premium gasoline, which the GS 450h requires. Your actual fuel costs may vary based on your driving habits, location, and fuel prices. Someone driving mainly in the city may see even lower fuel costs because the hybrid system works well in urban environments.

Real-world expectations

While the EPA provides standardized testing, real-world fuel economy always varies. Expect figures within a few MPG of the stated ratings if you drive moderately and follow speed limits. Quick acceleration and hard braking will reduce fuel efficiency. Terrain, weather, and vehicle load also affect mileage. Premium fuel is required because using regular unleaded could negatively affect performance and potentially long-term engine health and erase any savings at the pump.

How it compares

The GS 450h compares well to its direct competitors in fuel efficiency. The BMW 530e plug-in hybrid, for example, achieves a combined EPA rating of 27 MPG when running as a hybrid after its initial full-electric range. The Mercedes-Benz E350, with its gasoline engine, typically gets numbers in the mid-20s for combined MPG. The Acura RLX Sport Hybrid, another hybrid competitor, has similar MPG numbers to the Lexus. Buyers often choose the GS 450h for the Lexus brand’s reliability and its smooth hybrid integration over chasing extremely low fuel consumption. For those looking for all Lexus fuel economy data, there are plenty of resources available, and you can research GS MPG across all years to see how this model has changed.

Tips to maximize efficiency

Take advantage of the GS 450h’s drive modes. The “Eco” mode prioritizes fuel efficiency by adjusting throttle response and climate control. In town or in slower traffic, “Eco” mode can improve your MPG without significantly sacrificing performance.

Monitor the energy flow display. The GS 450h has a screen showing how the hybrid system operates: electric power, gasoline engine, or energy regeneration during braking. Watching this display can help you adjust your driving to maximize the electric motor’s use, especially in city driving.

Avoid quick acceleration and braking. The hybrid system is most efficient when operating smoothly. Gentle acceleration and predicting traffic allow the regenerative braking system to capture energy and recharge the battery, improving overall fuel economy.

Keep your tires properly inflated. Underinflated tires increase rolling resistance, which can reduce fuel efficiency. Check your tire pressure regularly and maintain the recommended pressure listed on the driver’s side doorjamb.

Reduce unnecessary weight. Too much cargo in the trunk or rear seats increases the vehicle’s weight and reduces fuel economy. Remove unnecessary items to lighten the load and improve your MPG.