2018 Honda Civic Si 2Dr: MPG and fuel economy
The 2018 Honda Civic Si 2Dr is rated by the U.S. Environmental Protection Agency at 32 combined MPG, with 28 MPG in the city and 38 MPG on the highway. That sits a little above the average car in the Compact Cars class for the same model year.
This page collects every fuel-economy figure the EPA publishes for the 2018 Honda Civic Si 2Dr. Below you will find the headline combined, city, and highway MPG, the estimated annual fuel cost at three different driving levels, the tailpipe CO₂ emissions, and a full breakdown of the engine and drivetrain. If you want to know whether this generation got more or less efficient over the years, the year-over-year table further down covers every model year the EPA has rated.
Key takeaways
- The most efficient car in the Compact Cars class for the 2018 model year is the Volkswagen e-Golf at 119 MPG.
- Requires premium gasoline, which typically adds about 40 to 60 cents per gallon to the EPA's annual fuel cost estimate.
Fuel economy at a glance
These are the EPA's official ratings for the 2018 Honda Civic Si 2Dr. The numbers come from a standardised laboratory test cycle and are the same figures that appear on the window sticker of every new car. Real-world mileage varies with driving style, weather, fuel quality, and how heavily loaded the car is.
Combined MPG is a 55/45 weighted blend of the city and highway test cycles. The EPA uses it as the single number you can compare across the entire dataset, including hybrids and EVs (which use the equivalent MPGe figure).
| Combined MPG | 32 MPG |
| City MPG | 28 MPG |
| Highway MPG | 38 MPG |
| Annual fuel cost | $2,150 |
| Tailpipe CO₂ | 279 g/mi |
| Fuel type | Premium |
How the 2018 Honda Civic Si 2Dr compares
The 2018 Honda Civic Si 2Dr returns 32 combined MPG. Cars in the Compact Cars class for the same model year average 28 MPG, which puts this car ahead of the class average by about 14%.
The most efficient car in the Compact Cars class for the 2018 model year is the Volkswagen e-Golf at 119 MPG. The bar chart below puts the Honda Civic Si 2Dr alongside the class best and the class average so you can see the full picture.
For broader context, the average new car of the 2018 model year (across all classes) returns 25.6 MPG. Larger vehicles pull the all-cars average down, so do not use that figure on its own to judge a small car or a hybrid. The full list of the most efficient cars of the 2018 model year is on its own page.
Annual fuel cost across driving patterns
The headline annual fuel cost the EPA publishes assumes 15,000 miles of driving per year and a fuel mix of 55% city and 45% highway. The dollar figure is calculated using the EPA's current reference price for premium gasoline, which is $4.61/gallon. EPA updates that reference periodically rather than tracking live pump prices, so treat it as a window-sticker estimate rather than today's pump number.
The table below scales the EPA's number to three common driving patterns. The combined MPG and the reference fuel price stay constant, only the annual mileage changes. To get a current-prices estimate, take your local gas price and multiply by 468.8 gallons (the car's annual consumption at the rated MPG).
| Driving pattern | Estimated annual fuel cost |
|---|---|
| Light driver, 7,500 miles per year | $1,075 |
| Average driver, 15,000 miles per year | $2,150 |
| Heavy driver, 25,000 miles per year | $3,583 |
Year-over-year MPG for the Honda Civic Si 2Dr
The EPA has rated the Honda Civic Si 2Dr across 2 model years, from 2017 Honda Civic Si 2Dr through 2018 Honda Civic Si 2Dr. The numbers below are the best combined MPG figure the EPA published for each year, which lets you see when the car was at its most efficient and how recent generations stack up.
Combined MPG has stayed in roughly the same range across the run, hovering close to 32 MPG.
| Year | Combined MPG | Open year page |
|---|---|---|
| 2018 | 32 MPG | this page |
| 2017 | 32 MPG | 2017 Honda Civic Si 2Dr |
Compare against other Compact Cars for 2018
If you are cross-shopping the 2018 Honda Civic Si 2Dr, the most useful comparison is against the other cars in the Compact Cars class for the same model year. The list below shows the highest-MPG peers, ranked from most to least efficient. Click any of them to open its full page.
The Volkswagen e-Golf leads this group at 119 MPG, 87 MPG ahead of the 2018 Honda Civic Si 2Dr.
Specifications
The 2018 Honda Civic Si 2Dr runs a 1.5-liter 4-cylinder turbocharged engine paired with a manual 6-spd, sending power through front-wheel drive.
Engine, transmission, and drivetrain together drive most of the variation in fuel economy across trims. A larger engine moves the car with less effort but burns more fuel. A turbo lets a small engine punch above its weight, often without much MPG penalty. All-wheel drive adds traction and weight, and usually costs a couple of MPG compared with two-wheel drive of the same engine.
- Vehicle class
- Compact Cars
- Engine
- 1.5L 4-cylinder turbocharged
- Transmission
- Manual 6-spd
- Drivetrain
- Front-Wheel Drive
- Fuel type
- Premium
- Annual petroleum use
- 9.3 barrels per year
Common questions about the 2018 Honda Civic Si 2Dr
Quick answers to the questions people most often search for when looking up the 2018 Honda Civic Si 2Dr.
-
Is the 2018 Honda Civic Si 2Dr fuel efficient?
Yes. The 2018 Honda Civic Si 2Dr returns 32 combined MPG, which beats the average car in the Compact Cars class for the same model year by about 14%. -
What MPG does the 2018 Honda Civic Si 2Dr get?
The EPA rates the 2018 Honda Civic Si 2Dr at 32 combined MPG, 28 MPG in city driving, and 38 MPG on the highway. Real-world numbers depend on your driving style, the weather, and how loaded the car is. -
How much does it cost to fuel a 2018 Honda Civic Si 2Dr per year?
The EPA estimates an annual fuel cost of $2,150 for the 2018 Honda Civic Si 2Dr. That figure assumes 15,000 miles of driving per year, a 55% city and 45% highway split, and the EPA's published average fuel price for the rated fuel grade. -
Does the 2018 Honda Civic Si 2Dr require premium gas?
Yes. The EPA lists the 2018 Honda Civic Si 2Dr as requiring premium gasoline. Running it on regular can reduce performance and may affect engine warranties, so it is not a recommended way to save at the pump. -
How much CO₂ does the 2018 Honda Civic Si 2Dr emit?
Tailpipe CO₂ emissions are 279 g/mi. Multiplied across a typical year of driving (15,000 miles) that works out to about 4,185 kilograms of CO₂. -
What is the difference between the city and highway MPG of the 2018 Honda Civic Si 2Dr?
City driving returns 28 MPG and highway driving returns 38 MPG, a gap of 10 MPG. A spread that wide is typical of cars with conventional automatic or manual transmissions, where stop-start city traffic eats more fuel than a steady highway cruise. -
What engine is in the 2018 Honda Civic Si 2Dr?
The 2018 Honda Civic Si 2Dr has a 1.5-liter 4-cylinder turbocharged engine (EPA description: SIDI). Smaller turbocharged engines like this one tend to deliver bigger-engine power on demand while keeping fuel economy closer to a non-turbo version of the same displacement. -
What transmission and drivetrain does the 2018 Honda Civic Si 2Dr have?
The 2018 Honda Civic Si 2Dr comes with a manual 6-spd transmission and front-wheel drive. -
How does the 2018 Honda Civic Si 2Dr compare to the best car in its class?
The most efficient car in the Compact Cars class for the 2018 model year is the Volkswagen e-Golf at 119 combined MPG. The Honda Civic Si 2Dr returns 32 MPG, a gap of 87 MPG. If you are comparing on fuel economy alone, the class leader is worth a look. -
How much petroleum does the 2018 Honda Civic Si 2Dr use per year?
The EPA estimates the 2018 Honda Civic Si 2Dr consumes about 9.3 barrels of petroleum per year, based on the standard 15,000 miles of driving. A barrel is 42 U.S. gallons of crude oil, which is refined into gasoline plus other products.
Source: U.S. EPA fuel economy dataset. Annual fuel cost figures assume 15,000 miles of driving per year and a 55% city, 45% highway split. Real-world mileage varies with driving conditions, vehicle maintenance, fuel quality, and driver behaviour.