23 MPG combined for the 2025 Lexus IS 350 3.5L 6-cyl states where this car sits in the performance luxury sedan segment. This isn’t the car for someone prioritizing outright efficiency above all else. Instead, it’s for the driver who values the immediate, linear power delivery of a naturally aspirated V6, the refined composure of a rear-wheel-drive platform, and the distinctive Lexus blend of reliability and luxurious cabin experience. The IS 350 caters to a buyer who understands that sporting intentions and effortless acceleration often come with a moderate thirst, and for them, 23 MPG is a perfectly acceptable trade-off for the engaging drive and premium feel. This figure speaks to the car’s character as a driver’s machine, unburdened by extreme eco-consciousness but far from wasteful.

City and highway performance

For specifics, the 2025 IS 350 achieves 20 MPG in city driving and 28 MPG on the highway. The city figure, at 20 MPG, accurately reflects the experience of navigating stop-and-go traffic. The 3.5-liter V6, while not turbocharged, still provides ample low-end torque for quick take-offs, and the well-calibrated 8-speed automatic transmission is smooth, minimizing harsh shifts that could impact efficiency in urban environments. However, the engine’s displacement and the vehicle’s weight mean that frequent acceleration and deceleration cycles will inevitably lead to consumption at this level. On the open road, the 28 MPG highway rating is respectable. This is where the V6 settles into its stride, using the higher gears of the automatic transmission and the car’s aerodynamic profile. Long cruises are effortless, the engine humming along at relatively low RPMs, contributing to both occupant comfort and the better highway efficiency. This balance underscores the IS 350’s dual nature, capable of lively city commutes and composed, efficient highway travel alike.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,500 for the 2025 Lexus IS 350. This figure is derived assuming 15,000 miles of driving per year, with a distribution of 45% highway and 55% city driving, and using national average fuel prices, which are updated periodically. Buyers of the IS 350 are generally not deterred by this figure. For them, the $2,500 annual expense is a manageable component of owning a premium sport sedan. It’s an investment in the tangible benefits of the vehicle: the crisp throttle response, the precise steering, the high-quality interior, and the peace of mind associated with the Lexus brand. Understanding this annual cost helps prospective owners budget accurately, ensuring that the driving pleasure of the IS 350 remains unmarred by unexpected financial surprises at the pump.

Real-world expectations

In real-world driving conditions, most IS 350 owners will find the EPA estimates to be quite achievable, assuming a relatively balanced driving style. Aggressive driving, with frequent heavy acceleration and braking, will predictably dip the city MPG closer to the mid-to-high teens. Conversely, a driver who is conscious of their throttle input and anticipates traffic flow can often exceed the 20 MPG city rating. On the highway, maintaining a consistent speed at or slightly below the speed limit will reliably deliver the 28 MPG figure, and in some cases, even push it into the low 30s during extended, flat-road cruising.

The naturally aspirated V6 rewards a smoother, more deliberate driving style. Constant short trips and heavy footed enthusiasm will always penalize fuel economy, regardless of the vehicle. For a car that encourages enthusiastic driving, the IS 350 performs commendably within its classification, offering a satisfying blend of power and practical efficiency for its intended audience. Many owners will consider the fuel economy a fair compromise for the engine’s character and responsiveness, especially when comparing it to smaller, turbocharged counterparts which often require premium fuel and can disappoint when driven hard.

How it compares

When stacked against its primary competitors, the 2025 Lexus IS 350’s 23 MPG combined rating places it squarely in the mix, often as an alternative for those prioritizing a specific powertrain characteristic. Consider the BMW 330i xDrive, which uses a 2.0-liter turbocharged four-cylinder engine and achieves a notably higher 27 MPG combined (23 city/33 highway). While the BMW offers superior efficiency, it comes at the expense of the IS 350’s linear V6 power delivery and signature exhaust note. Buyers cross-shopping these two will weigh the turbocharged four-cylinder’s punchy, low-end torque against the Lexus’s smoother, more refined six-cylinder feel. Another key rival, the Mercedes-Benz C300 4MATIC, also employs a 2.0-liter turbo-four, matching the BMW at 27 MPG combined (23 city/33 highway). Again, the C300 is more efficient, but the driving experience and engine character are distinctly different. For those considering the Audi A4 45 TFSI quattro, with its 2.0-liter turbocharged four-cylinder, the combined MPG is 27 (24 city/31 highway). The pattern is clear: forced induction four-cylinders generally beat the IS 350’s natural aspiration in terms of raw MPG. However, the IS 350’s choice of the 3.5L V6 is deliberate. It provides a distinct level of old-school luxury sport sedan engagement that many rivals, with their smaller, more boosted engines, simply cannot replicate. The buyers of the IS 350 are often those who specifically seek out that V6 refinement and naturally aspirated response, understanding that an additional few gallons a month is a small price to pay for that experience. You can explore all Lexus fuel economy data for a broader perspective, or dive into IS MPG across all years to see how this model has evolved.

Tips to maximize efficiency

One of the most effective ways to improve the IS 350’s fuel economy is to practice smooth acceleration and braking. The V6 engine is responsive, but constantly mashing the throttle and then aggressively braking wastes fuel. Adopt a more gradual approach to speed changes to allow the transmission to upshift earlier and stay in higher gears longer, reducing engine strain and consumption.

Maintain proper tire pressure. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressures monthly and ensure they match the recommendations found on the sticker inside your driver’s side door jamb, as this is a simple, cost-free way to maintain efficiency.

Plan your routes to avoid heavy traffic congestion whenever possible. Stop-and-go driving, particularly in urban environments, severely impacts the city MPG of the IS 350. Using navigation apps that offer real-time traffic updates can help you find less congested paths, reducing the amount of time the engine spends idling or in low, inefficient gears.

Consider using cruise control on highways. Maintaining a consistent speed helps the IS 350’s engine operate at its most efficient RPMs for extended periods. Avoiding unnecessary speed fluctuations prevents the engine from routinely demanding extra fuel for acceleration, maximizing that 28 MPG highway rating.

Regular maintenance is crucial. Keeping up with recommended oil changes, air filter replacements, and spark plug inspections ensures the 3.5L V6 operates at peak efficiency. A well-maintained engine burns fuel more completely and efficiently, directly contributing to better MPG and longevity for your IS 350.