If you’re looking at the 2025 Kia K4 as your next daily, fuel economy is probably near the top of your list. The K4 replaces the Forte but keeps the same smart formula: efficient 2.0-liter engine for most trims and a stronger 1.6-liter turbo for the GT-Line Turbo. The good news? Every K4 is easy on gas—and some trims hit 40 mpg highway according to EPA estimates.
Below is a clear breakdown of K4 MPG by trim, how it compares to rivals, and some real-world tips to get the best mileage.
Kia K4 MPG by Trim (EPA Estimates)
Based on dealer and EPA-linked info, here are the key numbers for the 2025 Kia K4 in the U.S.:
- K4 LX
- 30 city / 40 highway / 34 combined mpg
- K4 LXS
- 29 city / 39 highway / 33 combined mpg
- K4 EX
- 29 city / 39 highway / 33 combined mpg
- K4 GT-Line
- 29 city / 39 highway / 33 combined mpg
- K4 GT-Line Turbo (1.6L)
- 26 city / 36 highway / 29 combined mpg
All trims are designed to run on regular unleaded (87 octane or higher), so you don’t need to pay for premium fuel.
Quick takeaway
- If you want the best MPG, look at the LX and other 2.0-liter trims.
- If you want more power, the GT-Line Turbo still returns a respectable 29 mpg combined.
Engine Choices & Why MPG Changes
The K4 has two engines in the U.S. lineup:
- 2.0L 4-cylinder (147 hp / 132 lb-ft)
- Paired with an intelligent variable transmission (IVT/CVT-style).
- Prioritizes smoothness and efficiency.
- Powers LX, LXS, EX, GT-Line.
- 1.6L turbo 4-cylinder (190 hp / 195 lb-ft)
- Paired with an 8-speed automatic.
- More performance, more torque, slightly lower MPG.
- Exclusive to GT-Line Turbo.
The turbo engine’s extra power and different gearing naturally mean more fuel use, especially in city driving—hence the 26 mpg city vs 29–30 mpg on non-turbo trims.
Fuel Tank Size & Driving Range
According to Kia’s official specs, the K4 uses a 12.4-gallon fuel tank across the lineup.
Approximate highway ranges (simple estimate = highway mpg × 12.4 gallons):
- K4 LX (40 mpg highway) → about 496 miles per tank
- K4 LXS/EX/GT-Line (39 mpg highway) → about 483 miles
- K4 GT-Line Turbo (36 mpg highway) → about 446 miles
Actual results will vary with speed, load, terrain, weather, and driving style, but this gives you a realistic idea of how far you can go between stops.
How the K4 MPG Compares to Rivals
In the compact-sedan class (Civic, Corolla, Elantra, Mazda3), the K4 sits right in the middle to upper range on fuel economy:
- Non-turbo K4 (up to 34 combined mpg) is competitive with non-hybrid Civic and Corolla.
- Turbo rivals often drop into the high-20s combined—similar to the K4 GT-Line Turbo’s 29 combined mpg.
You only “lose” a few mpg by choosing the turbo, but you gain noticeably stronger acceleration and passing power.
Real-World Fuel Economy: What Drivers Can Expect
Third-party testing has shown that the GT-Line Turbo can match or even slightly beat its highway rating in steady cruising. For example, one instrumented test logged 35 mpg at 75 mph with the GT-Line Turbo, which is right on target with the 26/36/29 EPA window sticker.
In the city, expect:
- High 20s to low 30s mpg on the 2.0-liter trims.
- Mid-20s to upper 20s mpg on the turbo, depending heavily on how aggressively you drive.
Tips to Maximize Kia K4 MPG
Whether you pick the LX or GT-Line Turbo, you can squeeze more miles out of every gallon by:
- Using Eco or Normal drive modes for daily commuting instead of Sport mode.
- Keeping tires properly inflated—underinflation is one of the fastest ways to lose fuel economy.
- Driving smoothly: gentle acceleration and early upshifts save a lot of fuel over time.
- Avoiding long idling—turn the car off if you’re waiting for a while.
- Lightening the load—remove unnecessary cargo and roof racks when not needed.
These habits can easily add 1–3 mpg in real usage.
Which K4 Trim Is Best for Fuel Economy?
If MPG is your top priority:
- Pick the K4 LX for the highest official numbers (30/40/34 mpg).
- The LXS/EX/GT-Line still offer very solid 33 combined mpg and may come with more features you want.
If you want a blend of MPG + performance:
- Choose the GT-Line Turbo. You’ll still see around 29 mpg combined, which is very good for a 190-hp sedan, and enjoy a much stronger, more refined drive.
Related: 2025 Kia K4 Review: Interior, Specs, Trims & Pricing (USA)
FAQs
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1. Is the Kia K4 good on gas?
Yes. Most 2025 Kia K4 trims get up to 30 city / 40 highway / 34 combined mpg, which is competitive with other compact sedans in the U.S.
2. Which Kia K4 trim has the best fuel economy?
The K4 LX has the best official EPA rating at 30 city / 40 highway / 34 combined mpg. Other non-turbo trims (LXS/EX/GT-Line) are just behind at 29/39/33.
3. How much worse is the K4 GT-Line Turbo on gas?
The GT-Line Turbo is rated at 26 city / 36 highway / 29 combined mpg—just a few mpg lower than the 2.0-liter trims but with significantly more power.
4. What fuel does the Kia K4 use?
All K4 trims are designed for regular unleaded gasoline (87 octane or higher), so you don’t need premium fuel to get rated performance and MPG.
5. How big is the Kia K4 fuel tank and what range can I expect?
The 2025 K4 uses a 12.4-gallon tank. At 34 combined mpg, that’s roughly 420+ miles of mixed driving per fill-up, with highway range pushing toward 500 miles on the most efficient trims.
