20 MPG combined isn’t going to win the 2024 Lexus IS 500 any fuel economy awards, but that’s hardly the point. This isn’t a commuter car; it’s a shout from Lexus that driving pleasure still matters. It’s a naturally aspirated V8 in a world increasingly dominated by turbocharged fours and hybrids, and the compromise in fuel efficiency is one its buyers willingly accept for the visceral thrill it provides.

City and highway performance

The IS 500’s EPA ratings break down to 17 MPG in the city and 25 MPG on the highway. The city figure reflects the engine’s thirst when constantly accelerating from stops and navigating traffic. The highway number is more palatable, and achievable during steady-state cruising. But even on the open road, dipping into the throttle will quickly remind you that eight cylinders are working hard under the hood. The eight-speed automatic transmission, while generally smooth and responsive, is geared to prioritize performance over ultimate efficiency, further contributing to these figures. For a look at all Lexus fuel economy data, you can check our Lexus brand page.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2024 Lexus IS 500 at $2,900. This figure is based on driving 15,000 miles per year and using national average fuel prices. Keep in mind that premium fuel is recommended for this engine, so using regular fuel will not lower the annual fuel cost, but would instead have a negative effective on performance. Individual fuel costs will vary based on driving habits, location, and fluctuations in fuel prices, but $2,900 is a reasonable baseline to understand the expected running costs given typical use.

Real-world expectations

Achieving the EPA’s 20 MPG combined rating in the real world will require considerable restraint. Owners who frequently indulge in the IS 500’s performance capabilities are likely to see figures closer to the city rating, if not slightly lower. Conversely, those who primarily use the car for long highway trips with minimal stop-and-go driving could potentially match or even slightly exceed the 25 MPG highway rating. Those planning on using their IS 500 for track days and spirited driving events can expect single-digit fuel economy on those days.

How it compares

Competitors like the BMW M340i, with its turbocharged inline-six, boast significantly better fuel economy, achieving an EPA-estimated 26 MPG combined. Even the V6-powered Acura TLX Type S manages 21 MPG combined. The Cadillac CT5-V, despite offering similar levels of performance to the IS 500, achieves 18 MPG combined with its supercharged V8. These differences matter to buyers focused on minimizing running costs. The IS 500’s target demographic, however, is more interested in the unique character and sound of a naturally aspirated V8. For many, it’s an emotional purchase, and the fuel economy is a secondary consideration. If you are also trying to compare IS MPG across all years, you can see the difference between the models.

Tips to maximize efficiency

The IS 500 offers selectable drive modes, and engaging Eco mode can modestly improve fuel economy by adjusting throttle response and shift points. However, be aware that this significantly dulls the car’s performance, negating much of the V8’s appeal.

Gentle acceleration and anticipation of traffic flow are crucial to maximizing fuel efficiency. Avoid unnecessary hard braking and try to maintain a steady speed whenever possible. The IS 500 is sensitive to aggressive driving habits, and even small changes in driving style can yield noticeable improvements in MPG.

Proper tire inflation is essential for optimal fuel economy, as underinflated tires increase rolling resistance. Check your tire pressures regularly and ensure they are inflated to the recommended levels, which can be found on a sticker inside the driver’s side door jamb.

Minimize idling time. Letting the engine idle for extended periods consumes fuel without covering any distance. If you anticipate being stopped for more than a minute or two, turn off the engine. This is especially important on cold starts, which consume additional fuel. Cold starts are essential in keeping the engine running properly for years to come.