Compare the2025 Kia K4VS 2025 Mazda 3

Both the K4 and the Mazda 3 have standard driver and passenger frontal airbags, front and rear side-impact airbags, side-impact head airbags, front and rear seatbelt pretensioners, front wheel drive, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, driver alert monitors, available blind spot warning systems, around view monitors and rear cross-path warning.

The K4 comes with a full 5-year/60,000-mile basic warranty, which covers the entire car and includes 24-hour roadside assistance. The 3’s 3-year/36,000-mile basic warranty expires 2 years or 24,000 miles sooner.

Kia’s powertrain warranty covers the K4 5 years and 40,000 miles longer than Mazda covers the 3. Any repair needed on the engine, transmission, axles, joints or driveshafts is fully covered for 10 years or 100,000 miles. Coverage on the Mazda 3 ends after only 5 years or 60,000 miles.

There are over 45 percent more Kia dealers than there are Mazda dealers, which makes it easier should you ever need service under the K4’s warranty.

To reliably power the ignition and other systems and to recharge the battery, the K4 has larger alternators than the Mazda 3:

J.D. Power and Associates’ 2024 Initial Quality Study of new car owners surveyed provide the statistics that show that Kia vehicles are better in initial quality than Mazda vehicles. J.D. Power ranks Kia fourth in initial quality, above the industry average. With 69 more problems per 100 vehicles, Mazda is ranked 29th, below the industry average.

The K4 GT-Line Turbo’s standard 1.6 turbo 4-cylinder produces 9 lbs.-ft. more torque (195 vs. 186) than the Mazda 3’s standard 2.5 DOHC 4-cylinder.

As tested in Motor Trend the K4 GT-Line Turbo 1.6 turbo 4-cylinder is faster than the Mazda 3 4 cyl. (automatics tested):

On the EPA test cycle the K4 gets better mileage than the Mazda 3 Sedan:

On the EPA test cycle the K4 gets better mileage than the Mazda 3 Hatchback:

To lower fuel costs and make buying fuel easier, the Kia K4 uses regular unleaded gasoline. The Mazda 3 with the 2.5 turbo 4-cylinder engine requires premium for maximum efficiency, which can cost on average about 84.9 cents more per gallon.

An eight-speed automatic is standard on the Kia K4 GT-Line Turbo, for better acceleration and lower engine speed on the highway. Only a six-speed automatic is available for the Mazda 3.

The K4 has a standard continuously variable transmission (CVT). With no “steps” between gears, it can keep the engine at the most efficient speed for fuel economy, or keep it at its peak horsepower indefinitely for maximum acceleration. The Mazda 3 doesn’t offer a CVT.

For better stopping power the K4 GT-Line Turbo’s front brake rotors are larger than those on the Mazda 3:

The K4 stops shorter than the Mazda 3:

For better traction, the K4 GT-Line’s tires are larger than the largest tires available on the Mazda 3 (235/40R18 vs. 215/45R18).

The K4 LX/LXS’ standard tires provide better handling because they have a lower 55 series profile (height to width ratio) that provides a stiffer sidewall than the Mazda 3 2.5 S Sedan’s standard 60 series tires. The K4 GT-Line’s tires have a lower 40 series profile than the Mazda 3 Select Sport/Preferred/Carbon/Premium’s 45 series tires.

For superior ride and handling, the K4 GT-Line has fully independent front and rear suspensions. An independent suspension allows the wheels to follow the road at the best angle for gripping the pavement, without compromising ride comfort. The Mazda 3 has a solid rear axle, with a non-independent rear suspension.

The K4 GT-Line has front and rear stabilizer bars, which help keep the K4 GT-Line flat and controlled during cornering. The Mazda 3’s suspension doesn’t offer a rear stabilizer bar.

The K4 has vehicle speed sensitive variable-assist power steering, for low-effort parking, better control at highway speeds and during hard cornering, and a better feel of the road. The Mazda 3 doesn’t offer variable-assist power steering.

The K4 GT-Line Turbo handles at .87 G’s, while the Mazda 3 Carbon Edition Sedan AWD pulls only .79 G’s of cornering force in a Motor Trend skidpad test.

The K4 GT-Line Turbo executes Motor Trend’s “Figure Eight” maneuver 1.5 seconds quicker than the Mazda 3 Carbon Edition Sedan AWD (26.6 seconds @ .68 average G’s vs. 28.1 seconds @ .58 average G’s).

Because it has more passenger and cargo room, the EPA rates the K4 a Mid-size car, while the Mazda 3 is rated a Compact.

The K4 has 5.9 cubic feet more passenger volume than the Mazda 3 Sedan (98.7 vs. 92.8).

The K4 has 1 inch more front headroom, .8 inches more front shoulder room, 2.9 inches more rear legroom, 1 inch more rear hip room and 1.2 inches more rear shoulder room than the Mazda 3 Sedan.

The K4 has a much larger trunk than the Mazda 3 Sedan (14.6 vs. 13.2 cubic feet).

To make loading groceries and cargo easier when your hands are full, the K4’s trunk can be opened just by waiting momentarily behind the back bumper, leaving your hands completely free. The Mazda 3 doesn’t offer a hands-free gesture to open its trunk, forcing you to put cargo down if your hands are full.

The K4 GT-Line’s optional easy entry system glides the driver’s seat back when the door is unlocked or the ignition is switched off, making it easier for the driver to get in and out. The Mazda 3 doesn’t offer an easy entry system.

The power windows standard on both the K4 and the Mazda 3 have locks to prevent small children from operating them. When the lock on the K4 is engaged the driver can still operate all of the windows, for instance to close one opened by a child. The Mazda 3 prevents the driver from operating the other windows just as it does the other passengers.

The K4’s standard Smart Key allows you to unlock the doors from either front door handle, open the trunk, and start the engine, all without removing the key from the pocket or purse. Push Button Start standard on the Mazda 3 only offers hands-free access for the ignition, none to unlock the car. Push Button Start is not available on the Mazda 3 Select Sport/Preferred/Carbon/Premium.

The K4’s standard outside mirrors include heating elements to clear off the mirrors for better visibility. Mazda only offers heated mirrors on the Mazda 3 Select Sport/Preferred/Carbon/Premium.

Optional air-conditioned seats in the K4 GT-Line keep the driver and front passenger comfortable and take the sting out of hot seats in Summer. The Mazda 3 doesn’t offer air-conditioned seats.

The Kia K4 outsold the Mazda 3 by over four to one during 2023.