2021 Kia Niro — Full Specifications
As an Amazon Associate and CJ Affiliate and AWIN publisher we earn from qualifying purchases. Links below are affiliate links.
Running gear matters most — before anything else, UK: check tyre prices at TirendoUS: check wheel & tyre prices at WheelHero for this car's fitment.
The 2021 Kia Niro is an estate/wagon powered by a 1.6L 4-cyl regular gasoline engine. Its most fuel-efficient configuration returns around 55 mpg (UK) / 46 mpg (US EPA) combined, with 52–55 mpg (UK) across all configurations. Owners often keep a Kia Niro workshop manual to hand for servicing and repairs.
Compared with the 2020 Kia Niro: Fuel economy slips from 59 to 55 mpg (UK) combined on the most efficient configuration. The engine line-up listed by EPA is unchanged. It carries the same 4★ overall NHTSA rating.
Full Specifications
| Engine | 1.6L 4-cyl |
|---|---|
| Transmission | Automatic (AM-S6) |
| Fuel Type | Regular Gasoline |
| Powertrain | Plug-in Hybrid |
| Drive | Front-Wheel Drive |
| Body Style | Estate/Wagon |
| Passenger Volume (EPA) | 101 cu ft (2,860 L) |
| Luggage Volume (EPA) | 22 cu ft (623 L) |
| Fuel Economy (UK) | 55 combined / 58 urban / 53 extra-urban mpg |
| Fuel Economy (US EPA) | 46 combined / 48 city / 44 highway mpg |
| CO₂ Emissions | 56 g/km |
| EPA Greenhouse Gas Score | 9 / 10 (10 = lowest emissions) |
| EPA Est. Annual Fuel Cost | $1,450 (15,000 mi/yr, US prices) |
Engine & Transmission Options
EPA lists 2 configurations for the 2021 Kia Niro, all with the 1.6L 4-cyl engine. Combined fuel economy ranges from 43 to 46 mpg (US), or 52 to 55 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 |
|---|---|---|---|---|---|---|
| 1.6L 4-cyl (Hybrid) | Automatic (AM-S6) | Front-Wheel Drive | 52 | 43 (46/40) | 129 | $1,350 |
| 1.6L 4-cyl (Plug-in Hybrid) | Automatic (AM-S6) | Front-Wheel Drive | 55 | 46 (48/44) | 56 | $1,450 |
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 101 cubic feet (about 2,860 litres) and luggage volume at 22 cubic feet (about 623 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 Kia Niro
Running Costs: 2021 Kia Niro
Covering around 8,000 miles a year in a 2021 Kia Niro at 55 mpg combined, expect roughly 661 litres of fuel annually — multiply by your local price per litre for a cost estimate. For US owners, the EPA estimates about $1,450 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.
Planning a road trip? Grab a road trip packing list. Only need this car occasionally? See our buy vs rent comparison.
2021 Kia Niro Safety Ratings (NHTSA)
Recalls & Owner Complaints (NHTSA)
NHTSA lists 1 safety recall campaign that include the 2021 Kia Niro (as of 6 October 2026). Most affected areas: Power train (1). A campaign often covers several model years or models, so check your own VIN to see whether your car is affected.
- Power train — campaign 23V534000, reported 31 July 2023. Risk: A fire increases the risk of injury.
Owners have filed 12 complaints with NHTSA about the 2021 Kia Niro. The most-reported areas are Power train (4), Unspecified (2), Engine (2). Complaints include 1 reported crash, 1 reported injury. That is well below the median of 64 complaints across the 10 Kia Niro model years in our data.
Used-buyer checklist for the 2021 Kia Niro
Based on where NHTSA recalls and owner complaints cluster for this model year, these are the areas worth checking before you buy:
- Transmission & drivetrain (1 recall campaign · 4 owner complaints) — On the test drive, watch for hesitation, jerking or slipping between gears and ask for transmission service history.
- Engine (2 owner complaints) — Listen for unusual noise on a cold start, check for warning lights and ask for the service records.
- Electrical system (2 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
How does the Kia Niro compare to similar estate/wagons? For context, estate/wagons in our database average around 34 mpg (UK) combined — this model's 55 mpg figure is 21 mpg better than that average. Its 56 g/km CO₂ figure is 147 g/km lower than the 203 g/km average for estate/wagons on this site. This comparison is based on 194 estate/wagons in our dataset.
Kia models in our database average about 34 mpg (UK) combined on their most efficient configuration; the 2021 Kia Niro's 55 mpg is 21 mpg above that make average. Its 56 g/km CO₂ figure is 151 g/km lower than the 207 g/km Kia average.
Of the 10 Kia Niro model years we cover, the 2021 ranks 10th for combined fuel economy on its best configuration (55 mpg UK combined, against a high of 59 mpg). See every Kia Niro 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 Kia Niro
Frequently Asked Questions
What engine does the 2021 Kia Niro have?
It's fitted with a 1.6L 4-cyl regular gasoline engine, paired with a automatic (am-s6) transmission.
What is the fuel economy of the 2021 Kia Niro?
The most efficient configuration returns around 55 mpg (UK) combined, or 46 mpg on the US EPA cycle. Across all configurations the UK combined figure runs from 52 to 55 mpg.
How much does the 2021 Kia Niro cost to fuel per year?
The US EPA estimates about $1,450 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 Kia Niro have a good safety rating?
It holds an overall NHTSA rating of 4 stars, with 4 stars for frontal crash protection.
Does the 2021 Kia Niro have any recalls?
NHTSA lists 1 safety recall campaign that include the 2021 Kia Niro (as of 6 October 2026). Most affected areas: Power train (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 Kia Niro?
Among the 12 owner complaints filed with NHTSA, the most-reported areas are Power train (4 complaints), Unspecified (2 complaints), Engine (2 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 Kia Niro have?
EPA measures interior passenger volume at 101 cubic feet (about 2,860 litres) and luggage volume at 22 cubic feet (about 623 litres). These are US EPA interior-volume figures, which are measured differently from the UK boot-capacity numbers manufacturers quote.
Is the Kia Niro's fuel economy good for an estate/wagon?
Yes — it returns around 55 mpg (UK) combined, against a same-body-style average of roughly 34 mpg among the estate/wagons we track, making it one of the more efficient options in its class.