2018 Hyundai Sonata Plug-in Hybrid: MPG and fuel economy
The 2018 Hyundai Sonata Plug-in Hybrid is a plug-in hybrid rated at 39 combined MPG by the U.S. Environmental Protection Agency. It returns 37 MPG in the city and 42 MPG on the highway.
This page collects every fuel-economy figure the EPA publishes for the 2018 Hyundai Sonata Plug-in Hybrid. 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
- Returns 20% better combined MPG than the average car in the Midsize Cars class for the 2018 model year (32.6 MPG class average).
- The most efficient car in the Midsize Cars class for the 2018 model year is the Hyundai Ioniq Electric at 136 MPG.
- EPA estimates this car saves around $5,250 in fuel over five years compared with an average new vehicle of the same model year.
Fuel economy at a glance
These are the EPA's official ratings for the 2018 Hyundai Sonata Plug-in Hybrid. 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 | 39 MPG |
| City MPG | 37 MPG |
| Highway MPG | 42 MPG |
| Annual fuel cost | $1,550 |
| Tailpipe CO₂ | 100 g/mi |
| Fuel type | Regular Gas and Electricity |
How the 2018 Hyundai Sonata Plug-in Hybrid compares
The 2018 Hyundai Sonata Plug-in Hybrid returns 39 combined MPG. Cars in the Midsize Cars class for the same model year average 32.6 MPG, which puts this car ahead of the class average by about 20%.
The most efficient car in the Midsize Cars class for the 2018 model year is the Hyundai Ioniq Electric at 136 MPG. The bar chart below puts the Hyundai Sonata Plug-in Hybrid 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 regular gasoline, which is $3.99/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 384.6 gallons (the car's annual consumption at the rated MPG).
| Driving pattern | Estimated annual fuel cost |
|---|---|
| Light driver, 7,500 miles per year | $775 |
| Average driver, 15,000 miles per year | $1,550 |
| Heavy driver, 25,000 miles per year | $2,583 |
Year-over-year MPG for the Hyundai Sonata Plug-in Hybrid
The EPA has rated the Hyundai Sonata Plug-in Hybrid across 4 model years, from 2016 Hyundai Sonata Plug-in Hybrid through 2019 Hyundai Sonata Plug-in Hybrid. 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 39 MPG.
| Year | Combined MPG | Open year page |
|---|---|---|
| 2019 | 39 MPG | 2019 Hyundai Sonata Plug-in Hybrid |
| 2018 | 39 MPG | this page |
| 2017 | 39 MPG | 2017 Hyundai Sonata Plug-in Hybrid |
| 2016 | 40 MPG | 2016 Hyundai Sonata Plug-in Hybrid |
Compare against other Midsize Cars for 2018
If you are cross-shopping the 2018 Hyundai Sonata Plug-in Hybrid, the most useful comparison is against the other cars in the Midsize 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 Hyundai Ioniq Electric leads this group at 136 MPG, 97 MPG ahead of the 2018 Hyundai Sonata Plug-in Hybrid.
Specifications
The 2018 Hyundai Sonata Plug-in Hybrid runs a 2-liter 4-cylinder engine paired with a automatic (am6), 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
- Midsize Cars
- Engine
- 2L 4-cylinder
- Transmission
- Automatic (AM6)
- Drivetrain
- Front-Wheel Drive
- Fuel type
- Regular Gas and Electricity
- Annual petroleum use
- 3.4 barrels per year
- Start-stop system
- Yes
Common questions about the 2018 Hyundai Sonata Plug-in Hybrid
Quick answers to the questions people most often search for when looking up the 2018 Hyundai Sonata Plug-in Hybrid.
-
Is the 2018 Hyundai Sonata Plug-in Hybrid fuel efficient?
Yes. The 2018 Hyundai Sonata Plug-in Hybrid returns 39 combined MPG, which beats the average car in the Midsize Cars class for the same model year by about 20%. -
What MPG does the 2018 Hyundai Sonata Plug-in Hybrid get?
The EPA rates the 2018 Hyundai Sonata Plug-in Hybrid at 39 combined MPG, 37 MPG in city driving, and 42 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 Hyundai Sonata Plug-in Hybrid per year?
The EPA estimates an annual fuel cost of $1,550 for the 2018 Hyundai Sonata Plug-in Hybrid. 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. -
What fuel does the 2018 Hyundai Sonata Plug-in Hybrid use?
The EPA lists the 2018 Hyundai Sonata Plug-in Hybrid as running on regular gasoline. Using a different grade than the manufacturer specifies can affect fuel economy and engine longevity. -
Has the Hyundai Sonata Plug-in Hybrid become more fuel efficient over time?
Combined MPG has stayed close to flat across the run. Both the earliest (2016 Hyundai Sonata Plug-in Hybrid, 40 MPG) and most recent (2019 Hyundai Sonata Plug-in Hybrid, 39 MPG) versions sit in the same range. -
How much CO₂ does the 2018 Hyundai Sonata Plug-in Hybrid emit?
Tailpipe CO₂ emissions are 100 g/mi. Multiplied across a typical year of driving (15,000 miles) that works out to about 1,500 kilograms of CO₂. -
What is the difference between the city and highway MPG of the 2018 Hyundai Sonata Plug-in Hybrid?
City driving returns 37 MPG and highway driving returns 42 MPG, a gap of 5 MPG. The two figures are close enough that the car will hold its rated efficiency well across most driving patterns. -
What engine is in the 2018 Hyundai Sonata Plug-in Hybrid?
The 2018 Hyundai Sonata Plug-in Hybrid has a 2-liter 4-cylinder engine (EPA description: SIDI; PHEV). -
What transmission and drivetrain does the 2018 Hyundai Sonata Plug-in Hybrid have?
The 2018 Hyundai Sonata Plug-in Hybrid comes with a automatic (am6) transmission and front-wheel drive. -
How does the 2018 Hyundai Sonata Plug-in Hybrid compare to the best car in its class?
The most efficient car in the Midsize Cars class for the 2018 model year is the Hyundai Ioniq Electric at 136 combined MPG. The Hyundai Sonata Plug-in Hybrid returns 39 MPG, a gap of 97 MPG. If you are comparing on fuel economy alone, the class leader is worth a look.
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.