2018 Kia Optima S MPG and Fuel Economy

On this page, you will find a complete guide to the miles per gallon and fuel efficiency data for the 2018 Kia Optima S.

The 2018 Kia Optima S runs on regular gasoline and is in the Large Cars car class.

Whether you are considering a purchase of the car, or just wanting to find out how economical and environmentally friendly (or un-friendly) your 2018 Kia Optima S is, we have the information you need.

🛣 How Many Miles per Gallon (MPG) Does a 2018 Kia Optima S Get?

First off, the most commonly asked question. A 2018 Kia Optima S gets up to 23 miles per gallon in the city, and 32 miles per gallon on the highway.

The combined average MPG for the 2018 Kia Optima S is 26 miles per gallon.

💵 What is the Average Yearly Fuel Cost for a 2018 Kia Optima S?

The estimated fuel costs for the 2018 Kia Optima S is $2,400 per year.

That value has been estimated by government regulators based on 15,000 miles driven per year, using regular gasoline, and a split of 55% city driving and 45% highway driving.

If you were to compare a 2018 Kia Optima S to an average vehicle over 5 years, you will spend $500 more on fuel.

🛢 How Many Barrels of Petroleum Does a 2018 Kia Optima S Consume?

The 2018 Kia Optima S will consume roughly 11 barrels of petroleum per year, using the standard estimate of 15,000 miles per year.

The majority of the world's petroleum is sourced from countries like Saudi Arabia, Russia, Iraq, and the United States.

💨 How Many Grams of CO2 Does a 2018 Kia Optima S Emit?

For every mile driven, the 2018 Kia Optima S will emit 340 grams of CO2, which is about 5,100,000 grams of CO2 per year.

🌳 To help you understand the impact of this, a normal tree will absorb around 21,000 grams of CO2 per year. This means that roughly 174 trees would be needed to offset emissions from the 2018 Kia Optima S.


The table below covers all of the miles per gallon, engine specifications, and emission details we have for the 2018 Kia Optima S.

City MPG 23
Highway MPG 32
Combined MPG 26
Save/Spend vs Average Car Spend $500
Fuel Cost $2,400
Fuel Type 1 Regular
Barrels of Petroleum 11
Grams of CO2 5,100,000
Trees Needed to Offset 243
Drive Front-Wheel Drive
Cylinders 4
Transmission Automatic (S6)
Vehicle Class Large Cars
Start/Stop? No
Supercharged? No
Turbocharged? No

Related Kia Models from 2018

If you're interested in other Kia models from 2018, you can find them in the table below. You can click the model link to find miles per gallon and emission information for that model.


Ratings were provided by the manufacturer to the U.S. Department of Energy, which is where we sourced the data. Be advised that manufacturers may have upgraded, downgraded, or changed these ratings following the compilation of this data.

MPG Buddy does not guarantee the accuracy of this data, nor are we liable for any decisions made by referencing this data. Make sure to contact the specific car manufacturer to confirm accuracy.

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  • "2018 Kia Optima S MPG and Fuel Economy". MPG Buddy. Accessed on August 15, 2022. http://mpgbuddy.com/cars/kia/optima-s/2018.

  • "2018 Kia Optima S MPG and Fuel Economy". MPG Buddy, http://mpgbuddy.com/cars/kia/optima-s/2018. Accessed 15 August, 2022

  • 2018 Kia Optima S MPG and Fuel Economy. MPG Buddy. Retrieved from http://mpgbuddy.com/cars/kia/optima-s/2018.