Kia Optima vs Mazda 6
This page compares the Kia Optima and the Mazda 6 across the 11 model years both appear in our data (2010–2020). Both are classed as Saloon/Sedan on this site. On its most efficient configuration the Kia Optima averages about 34 mpg (UK) against 33 mpg for the Mazda 6. NHTSA lists fewer recall campaigns per model year for the Mazda 6 (3.4 against 4.3), though campaign counts depend on how long each model has been on sale and how many variants share a campaign.
Head-to-Head: 2010–2020
| Measure | Kia Optima | Mazda 6 |
|---|---|---|
| Average best-configuration economy (mpg, UK) | 34 | 33 |
| Average CO₂ (g/km) | 195 | 200 |
| Average estimated annual fuel cost (US EPA) | $2,377 | $2,450 |
| Average passenger volume (cu ft, EPA) | 104 | 101 |
| Model years rated 5★ overall by NHTSA | 10 of 10 | 7 of 9 |
| Average recall campaigns per model year | 4.3 | 3.4 |
| Average owner complaints per model year | 589 | 80 |
| Engine options across these years | 5 | 3 |
Year by Year
| Year | Kia Optima MPG (UK) | NHTSA | Recalls | Complaints | Mazda 6 MPG (UK) | NHTSA | Recalls | Complaints |
|---|---|---|---|---|---|---|---|---|
| 2010 | 30 | — | 1 | 75 | 29 | — | 9 | 225 |
| 2011 | 32 | 5★ | 6 | 627 | 30 | — | 6 | 135 |
| 2012 | 32 | 5★ | 6 | 1,028 | 30 | 4★ | 6 | 99 |
| 2013 | 32 | 5★ | 10 | 1,438 | 29 | 4★ | 4 | 23 |
| 2014 | 31 | 5★ | 7 | 617 | 36 | 5★ | 4 | 137 |
| 2015 | 31 | 5★ | 4 | 1,021 | 36 | 5★ | 3 | 60 |
| 2016 | 37 | 5★ | 5 | 760 | 36 | 5★ | 1 | 77 |
| 2017 | 37 | 5★ | 4 | 305 | 35 | 5★ | 1 | 60 |
| 2018 | 37 | 5★ | 3 | 243 | 35 | 5★ | 2 | 58 |
| 2019 | 37 | 5★ | 1 | 211 | 35 | 5★ | 1 | 6 |
| 2020 | 37 | 5★ | 0 | 150 | 35 | 5★ | 0 | 2 |
MPG is each model year's most efficient configuration (US EPA, converted to UK mpg). Recalls and complaints are NHTSA counts as of 6 October 2026; complaints are unverified owner reports and rise with sales volume. See each model's full history: Kia Optima · Mazda 6.
Frequently Asked Questions
Which is more fuel-efficient, the Kia Optima or the Mazda 6?
On its most efficient configuration the Kia Optima averages about 34 mpg (UK) against 33 mpg for the Mazda 6. Figures are the US EPA combined result converted to UK mpg, averaged over the shared model years; individual engines and years differ, so check the year pages for the exact car.
Which has better NHTSA safety ratings?
The Kia Optima has 10 of 10 model years rated 5★ overall in these years and the Mazda 6 has 7 of 9. NHTSA ratings are only comparable between vehicles of similar size and weight, and the test criteria have changed over time.
Which has more recalls and owner complaints?
Per model year, the Kia Optima averages 4.3 recall campaigns and 589 owner complaints; the Mazda 6 averages 3.4 and 80. Complaint counts are unverified owner reports and rise with sales volume, so use them as a pointer for what to inspect, not as a reliability ranking.
Where do these comparison figures come from?
Fuel economy, CO₂ and interior volume come from the US EPA's fueleconomy.gov data; ratings, recalls and complaints come from NHTSA. Only model years where both cars have data are compared.
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