2026 head-to-head · Midsize Car
2026 Kia K4 vs Mazda 3
MPG, range and what each one really costs you to fuel, from official EPA ratings and recalculated with your own gas and electricity prices.
The 2026 Kia K4 is the cheaper one to run. Driving 15,000 miles a year with $3.10/gal regular gas, it costs about $1,409 a year to fuel (33 MPG), versus $1,550 for the 2026 Mazda 3 (30 MPG). That's roughly $141 a year, or about $705 over five years.
Your numbers
Change these to match your driving and local prices. Every figure and chart on this page updates.
Fuel cost over 10 years
- Kia K4
- Mazda 3
Side by side
| Kia K4 | Mazda 3 | |
|---|---|---|
| $1,409 | Your annual fuel cost | $1,550 |
| 33 MPG | Combined efficiency | 30 MPG |
| 29 MPG | City | 27 MPG |
| 39 MPG | Highway | 36 MPG |
| 99 cu ft | Passenger volume | 93 cu ft |
| 15 cu ft | Cargo volume | 13 cu ft |
| 269 g/mi | Tailpipe CO₂ (g/mi) | 294 g/mi |
| 6/10 | EPA fuel economy score | 6/10 |
| 6/10 | EPA greenhouse gas score | 6/10 |
| Gas | Powertrain | Gas |
| Regular gasoline | Fuel | Regular gasoline |
| 2.0L 4-cyl | Engine / motor | 2.5L 4-cyl |
| CVT | Transmission | 6-speed automatic |
| FWD | Drivetrain | FWD |
✓ marks the better value. EPA scores run 1–10 (10 is best). Volumes come from the EPA interior volume index and aren't published for every body style.
Kia K4 vs Mazda 3 across model years
- Kia K4
- Mazda 3
Annual fuel cost of the most efficient configuration of each model year, at your prices. Click a point to open that year.
How they differ
Per EPA interior volume figures, the Kia K4 has more passenger space (99 vs. 93 cu ft); the Kia K4 has more cargo space (15 vs. 13 cu ft).
Among 31 2026 midsize cars, the Kia K4 ranks 13th and the Mazda 3 15th for lowest fuel cost.
Frequently asked questions
Which is more fuel-efficient, the 2026 Kia K4 or the 2026 Mazda 3?
Measured by cost to drive, the Kia K4. The Kia K4 is rated 33 MPG combined and the Mazda 3 30 MPG (EPA, most efficient configuration of each).
How much does it cost to fuel the 2026 Kia K4 vs. the Mazda 3 per year?
At 15,000 miles a year with $3.10/gal regular gas, about $1,409 for the Kia K4 and $1,550 for the Mazda 3.
Which has more cargo space?
The Kia K4, with 15 cu ft of luggage volume versus 13 cu ft (EPA interior volume index).
Kia K4 vs Mazda 3 in other years
More 2026 comparisons
Kia K4 vs…
Or compare the 2026 Kia K4 with anything else: