67 MPG combined is exceptional, and it’s made possible by the 2017 Toyota Mirai’s hydrogen fuel cell powertrain. This isn’t your average hybrid or EV. The Mirai is a statement, a technological showcase specifically designed for a tiny fraction of the population who prioritize cutting-edge green technology above all else. It’s less about saving money and more about pioneering a zero-emissions future, despite the limitations that come with it.

City and highway performance

The EPA’s figures are remarkably consistent for the Mirai: 67 MPG city and 67 MPG highway. This unusual uniformity speaks to the nature of the fuel cell drivetrain. Unlike a traditional combustion engine that might see fluctuations in efficiency based on stop-and-go city driving versus steady highway cruising, the Mirai operates more consistently. Its electric motor delivers instant torque, and the fuel cell maintains a relatively stable output whether navigating urban congestion or maintaining highway speeds. The transmission technically has variable gear ratios but ultimately functions as one uniform process, unlike a traditional automatic transmission.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2017 Toyota Mirai at $784. This calculation is based on driving 15,000 miles per year and using the national average cost of hydrogen fuel at the time of testing. This number needs context. Because hydrogen fueling infrastructure is limited, the Mirai was primarily sold/leased in California and often came with substantial fuel credits that significantly reduced or even eliminated the real-world fueling costs for early adopters. While $784 is the official figure, understand that the actual out-of-pocket expense for most Mirai drivers was far lower, making the overall cost of ownership attractive despite the inherent limitations of hydrogen refueling.

Real-world expectations

While the EPA’s 67 MPG provides a baseline, real-world fuel economy can vary. Driving style, terrain, and weather conditions all play a role. Aggressive acceleration and frequent hard braking will deplete the hydrogen reserves more quickly, as will sustained high-speed highway driving. And, the availability and price of hydrogen fuel significantly impact the ownership experience. Because of the limited refueling infrastructure, “range anxiety” is a real concern, requiring careful planning and route optimization. Owners accept these limitations in exchange for the vehicle’s zero-emission credentials and its futuristic appeal.

How it compares

When examining all Toyota fuel economy data, the Mirai stands alone with its hydrogen fuel cell technology. Comparing it to other zero-emission vehicles, like the Tesla Model 3 Long Range (132 MPGe combined) or the Chevrolet Bolt EV (120 MPGe combined), is useful, but imperfect, these are battery-electric vehicles that use different units to measure efficiency. Consider that you can also compare that Toyota Prius (56 MPG combined) is far more practical and widely accessible, thanks to its hybrid system and gasoline fuel. The Mirai isn’t chasing the same buyer. It prioritizes a specific type of clean technology and a certain level of exclusivity, accepting limitations along the way.

Tips to maximize efficiency

Unlike a gasoline-powered car, the Mirai’s “fuel tank” slowly degrades when not in use, which can impact performance. If you plan to leave the vehicle parked for an extended period (more than a few days), it’s best to ensure it’s parked on a level surface and that the hydrogen tank is not completely full or empty. A half-full tank seems to be the sweet spot for longevity.

Anticipate traffic flow and avoid aggressive acceleration. The Mirai delivers instant torque, making it tempting to zip off the line, but smooth and steady acceleration will significantly improve hydrogen consumption. Use the regenerative braking feature to recapture energy during deceleration. This helps recharge the small battery pack and reduces the load on the fuel cell.

Plan your routes carefully. Knowing the location of hydrogen refueling stations and their operational status is critical to avoid range anxiety and unnecessary detours. Apps and websites dedicated to alternative fuel locations can be invaluable for the owners of the MIRAI MPG across all years.

Keep tires properly inflated. Underinflated tires increase rolling resistance, which reduces fuel efficiency. Check your tire pressure regularly and inflate them to the recommended level. Your Mirai’s door jamb will have a sticker indicating the ideal tire pressure.

Minimize accessory use. Features like air conditioning and the entertainment system draw power from the battery, which in turn increases the load on the fuel cell. Use these accessories judiciously to maximize your hydrogen reserves. Heating the cabin can be a particular drain, so pre-conditioning the cabin while plugged in to a charger (if possible) is a helpful strategy.