While 35 MPG combined from the 2018 BMW i3 with Range Extender might seem underwhelming with so many efficient hybrids and EVs available, remember the i3’s purpose. People don’t buy an i3 for long road trips or hauling materials. They buy it as a unique, stylish city car focused on sustainability and easy parking, and the 35 MPG is a bonus for a car that primarily runs on electricity. Most owners will rarely use the gasoline range extender, making that MPG almost irrelevant.

City and highway performance

The EPA numbers break down to 36 MPG in the city and 33 MPG on the highway. These figures show the Range Extender’s design limitations. The small 0.6L two-cylinder engine is built to maintain battery charge level, rather than propel the car. In stop-and-go city driving, the electric motor is the main power source, using regenerative braking to regain energy and reduce gasoline engine use. However, on the highway, where consistent speed and less braking require continuous power from the gasoline engine, MPG is lower. The gasoline engine is working harder on the highway.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 BMW i3 (94Ah) with Range Extender at $1,650. This is based on driving 15,000 miles per year, with a percentage of city and highway miles, using national average fuel prices at the time. This number can be much higher or lower depending on driving habits and how often you use the gasoline range extender. Owners who charge regularly and use the range extender sparingly can easily cut this cost in half or eliminate it completely. This figure also doesn’t include the cost of electricity, which could be significantly less than using the gas engine.

Real-world expectations

The EPA figure might be misleading, so expect different numbers in the real world. Someone who plugs in every night and drives short distances will see much better net fuel economy than someone who relies on the range extender. If a driver uses the full electric range (around 97 miles) and only uses the range extender for longer trips, they could achieve the equivalent of 70-80 MPG or higher. But drivers who treat the i3 as a conventional hybrid, rarely plugging in, will likely see numbers closer to that 35 MPG figure. Careful use of the “Hold State of Charge” mode can help manage when the gas engine starts.

How it compares

Compared to other plug-in hybrids and small EVs of its time, the 2018 BMW i3 with Range extender is unique. The Chevrolet Volt offered a higher electric range and around 42 MPG combined when the gasoline engine was running. The Toyota Prius Prime, another plug-in hybrid, gets around 54 MPG combined when operating as a hybrid. The pure electric Nissan Leaf offered better all-electric range, but zero MPG once the battery was depleted. These numbers highlight the i3’s priorities. It’s not the most efficient on gasoline, but it offers the style and BMW appeal that those other vehicles don’t. For a broader look at I3 MPG across all years, click here.

Tips to maximize efficiency

Use the i3’s regenerative braking system. By removing your foot from the accelerator, you can slow the car while replenishing the battery. Plan routes to anticipate stops, to maximize recovered energy.

Precondition the cabin while the car is plugged in. Use the My BMW app to heat or cool the interior before unplugging from the charger. This uses power from the grid rather than the battery while driving. Set charging for off-peak hours when possible to decrease the cost of electricity.

Avoid accelerating quickly. The electric motor’s instant torque is tempting, but rapid starts drain the battery. Smooth acceleration will extend electric range and reduce the need to activate the gasoline range extender. The driving modes Eco Pro and Comfort offer different strategies; experiment to see what meets your need.

Reduce highway driving when possible. While the i3 works well on the highway, its aerodynamic profile and range extender’s limitations make it less efficient at higher speeds. Choose slower routes or plan trips strategically to maximize electric-only driving in the city.

Check tire pressure regularly. Underinflated tires increase rolling resistance and reduce fuel efficiency. Check tire pressure monthly and inflate them to the recommended level. All Bmw fuel economy data can be found here.