2021 Mazda 3 — Full Specifications
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The 2021 Mazda 3 is a saloon/sedan offered with 3 engines (2L 4-cyl, 2.5L 4-cyl, 2.5L 4-cyl turbo). Its most fuel-efficient configuration returns around 37 mpg (UK) / 31 mpg (US EPA) combined, with 32–37 mpg (UK) across all configurations. Owners often keep a Mazda 3 workshop manual to hand for servicing and repairs.
Related 2021 listings: Mazda 3 4-Door, Mazda 3 5-Door.
Compared with the 2020 Mazda 3: Fuel economy is essentially unchanged at around 37 mpg (UK) combined. EPA lists new engine options for 2021: 2L 4-cyl, 2.5L 4-cyl turbo. It carries the same 5★ overall NHTSA rating.
Full Specifications
| Engine (most efficient) | 2L 4-cyl |
|---|---|
| Engine options | 2L 4-cyl · 2.5L 4-cyl · 2.5L 4-cyl turbo |
| Transmission (most efficient) | Automatic (S6) |
| Fuel Type | Regular Gasoline |
| Powertrain | Conventional |
| Drive | Front-Wheel Drive |
| Body Style | Saloon/Sedan |
| Passenger Volume (EPA) | 93 cu ft (2,633 L) |
| Luggage Volume (EPA) | 13 cu ft (368 L) |
| Fuel Economy (UK) | 37 combined / 34 urban / 43 extra-urban mpg |
| Fuel Economy (US EPA) | 31 combined / 28 city / 36 highway mpg |
| CO₂ Emissions | 178 g/km |
| EPA Greenhouse Gas Score | 6 / 10 (10 = lowest emissions) |
| EPA Est. Annual Fuel Cost | $2,150 (15,000 mi/yr, US prices) |
Engine & Transmission Options
EPA lists 5 configurations for the 2021 Mazda 3 across 3 engines (2L 4-cyl, 2.5L 4-cyl, 2.5L 4-cyl turbo). Combined fuel economy ranges from 27 to 31 mpg (US), or 32 to 37 mpg (UK), depending on engine, transmission and drive. The headline figures at the top of this page describe the most fuel-efficient configuration.
| Engine | Transmission | Drive | MPG (UK) | MPG (US) | CO₂ g/km | Fuel cost / yr |
|---|---|---|---|---|---|---|
| 2L 4-cyl | Automatic (S6) | Front-Wheel Drive | 37 | 31 (28/36) | 178 | $2,150 |
| 2.5L 4-cyl | Automatic (S6) | 4-Wheel Drive | 34 | 28 (25/33) | 199 | $2,400 |
| 2.5L 4-cyl | Automatic (S6) | Front-Wheel Drive | 36 | 30 (26/35) | 186 | $2,250 |
| 2.5L 4-cyl | Manual 6-spd | Front-Wheel Drive | 32 | 27 (24/33) | 201 | $2,500 |
| 2.5L 4-cyl turbo | Automatic (S6) | 4-Wheel Drive | 32 | 27 (23/32) | 208 | $2,500 |
MPG (US) shows combined, with city/highway in brackets. Highlighted row = the configuration used for the headline figures. Source: US EPA fueleconomy.gov.
EPA measures interior passenger volume at 93 cubic feet (about 2,633 litres) and luggage volume at 13 cubic feet (about 368 litres). These are US EPA interior-volume figures; they are measured differently from the boot capacity numbers UK manufacturers quote.
Owner Essentials for the 2021 Mazda 3
Running Costs: 2021 Mazda 3
Covering around 8,000 miles a year in a 2021 Mazda 3 at 37 mpg combined, expect roughly 983 litres of fuel annually — multiply by your local price per litre for a cost estimate. For US owners, the EPA estimates about $2,150 a year in fuel for the most efficient configuration (15,000 miles, national average prices). Work out exact fuel costs with the fuel cost calculator on 247Calculators.
Convert between MPG and L/100km with the unit converters on 247QuickTools. Not sure what tyre size fits? 247TyreCheck explains tyre sizing.
Only need this car occasionally? See our buy vs rent comparison.
2021 Mazda 3 Safety Ratings (NHTSA)
Recalls & Owner Complaints (NHTSA)
NHTSA lists 1 safety recall campaign that include the 2021 Mazda 3 (as of 6 October 2026). Most affected areas: Tires (1). A campaign often covers several model years or models, so check your own VIN to see whether your car is affected.
- Tires — campaign 21V101000, reported 22 February 2021. Risk: A sudden air leak from the tire air valve may cause a loss of vehicle control while driving, increasing the risk of a crash.
Owners have filed 52 complaints with NHTSA about the 2021 Mazda 3. The most-reported areas are Engine (19), Forward collision avoidance (7), Unspecified (7). Complaints include 2 reported crashes, 2 reported fires, 1 reported injury. That is close to the median of 83 complaints across the 17 Mazda 3 model years in our data.
Used-buyer checklist for the 2021 Mazda 3
Based on where NHTSA recalls and owner complaints cluster for this model year, these are the areas worth checking before you buy:
- Engine (19 owner complaints) — Listen for unusual noise on a cold start, check for warning lights and ask for the service records.
- Tyres (1 recall campaign) — Check tyre age and wear and ask about any tyre recalls.
- Driver-assist sensors (7 owner complaints) — Check that driver-assist warning lights are off and sensors are clean and undamaged.
- Electrical system (6 owner complaints) — Test every switch, window, light and warning lamp on a test drive, and ask about battery or alternator replacements.
Source: US NHTSA recall and consumer-complaint databases, retrieved 6 October 2026. Complaints are unverified owner reports, not confirmed defects. Check any vehicle by VIN at nhtsa.gov/recalls, and see our guide to checking a used car for recalls.
How It Compares
Mazda models in our database average about 34 mpg (UK) combined on their most efficient configuration; the 2021 Mazda 3's 37 mpg is 3 mpg above that make average. Its 178 g/km CO₂ figure is 20 g/km lower than the 198 g/km Mazda average.
Of the 17 Mazda 3 model years we cover, the 2021 ranks 7th for combined fuel economy on its best configuration (37 mpg UK combined, against a high of 40 mpg). See every Mazda 3 year side by side.
Last updated: · Data: US EPA (fueleconomy.gov) and NHTSA safety ratings 18 July 2026; NHTSA recalls and complaints 6 October 2026; Wikidata & curated EU catalogue 18 July 2026; European generation and engine data from Wikipedia 7 October 2026
Vehicle data sourced from manufacturer specifications. Always verify with your vehicle handbook or a qualified mechanic. This is a reference tool, not professional advice.
Recommended Accessories for the 2021 Mazda 3
Frequently Asked Questions
What engine does the 2021 Mazda 3 have?
EPA lists 3 engines for the 2021 Mazda 3: 2L 4-cyl, 2.5L 4-cyl, 2.5L 4-cyl turbo. The most fuel-efficient configuration pairs the 2L 4-cyl with a automatic (s6).
What is the fuel economy of the 2021 Mazda 3?
The most efficient configuration returns around 37 mpg (UK) combined, or 31 mpg on the US EPA cycle. Across all configurations the UK combined figure runs from 32 to 37 mpg.
How much does the 2021 Mazda 3 cost to fuel per year?
The US EPA estimates about $2,150 a year in fuel for the most efficient configuration, based on 15,000 miles of mixed driving and national average fuel prices. Your own cost will depend on mileage and local prices.
Does the 2021 Mazda 3 have a good safety rating?
It holds an overall NHTSA rating of 5 stars, with 5 stars for frontal crash protection.
Does the 2021 Mazda 3 have any recalls?
NHTSA lists 1 safety recall campaign that include the 2021 Mazda 3 (as of 6 October 2026). Most affected areas: Tires (1). A campaign often covers several model years or models, so check your own VIN to see whether your car is affected.
What are the most common problems reported for the 2021 Mazda 3?
Among the 52 owner complaints filed with NHTSA, the most-reported areas are Engine (19 complaints), Forward collision avoidance (7 complaints), Unspecified (7 complaints). Complaints are unverified owner reports, not confirmed defects, and raw counts rise with how many cars were sold.
How much interior and luggage space does the 2021 Mazda 3 have?
EPA measures interior passenger volume at 93 cubic feet (about 2,633 litres) and luggage volume at 13 cubic feet (about 368 litres). These are US EPA interior-volume figures, which are measured differently from the UK boot-capacity numbers manufacturers quote.