2021 Hyundai Ioniq — Full Specifications
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The 2021 Hyundai Ioniq is a hatchback powered by a 1.6L 4-cyl regular gasoline engine. Its most fuel-efficient configuration returns around 66 mpg (UK) / 55 mpg (US EPA) combined, with 62–66 mpg (UK) across all configurations. Owners often keep a Hyundai Ioniq workshop manual to hand for servicing and repairs.
Compared with the 2020 Hyundai Ioniq: Fuel economy is essentially unchanged at around 66 mpg (UK) combined. The engine line-up listed by EPA is unchanged.
Full Specifications
| Engine | 1.6L 4-cyl |
|---|---|
| Transmission | Automatic (AM-S6) |
| Fuel Type | Regular Gasoline |
| Powertrain | Hybrid |
| Drive | Front-Wheel Drive |
| Body Style | Hatchback |
| Passenger Volume (EPA) | 96 cu ft (2,718 L) |
| Luggage Volume (EPA) | 27 cu ft (765 L) |
| Fuel Economy (UK) | 66 combined / 65 urban / 67 extra-urban mpg |
| Fuel Economy (US EPA) | 55 combined / 54 city / 56 highway mpg |
| CO₂ Emissions | 101 g/km |
| EPA Greenhouse Gas Score | 10 / 10 (10 = lowest emissions) |
| EPA Est. Annual Fuel Cost | $1,200 (15,000 mi/yr, US prices) |
Engine & Transmission Options
EPA lists 2 configurations for the 2021 Hyundai Ioniq, all with the 1.6L 4-cyl engine. Combined fuel economy ranges from 52 to 55 mpg (US), or 62 to 66 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 | 66 | 55 (54/56) | 101 | $1,200 |
| 1.6L 4-cyl (Plug-in Hybrid) | Automatic (AM-S6) | Front-Wheel Drive | 62 | 52 (52/51) | 46 | $1,300 |
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 96 cubic feet (about 2,718 litres) and luggage volume at 27 cubic feet (about 765 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 Hyundai Ioniq
Running Costs: 2021 Hyundai Ioniq
Covering around 8,000 miles a year in a 2021 Hyundai Ioniq at 66 mpg combined, expect roughly 551 litres of fuel annually — multiply by your local price per litre for a cost estimate. For US owners, the EPA estimates about $1,200 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 Hyundai Ioniq Safety Ratings (NHTSA)
No NHTSA crash-test rating is on record for this model year. The NHTSA rates only a subset of vehicles each year; you can browse every rated vehicle on our NHTSA Safety Ratings hub.
Recalls & Owner Complaints (NHTSA)
NHTSA lists no safety recall campaigns for the 2021 Hyundai Ioniq as of 6 October 2026. Recalls can be issued years after a model is sold, so it is still worth checking your own VIN.
Owners have filed 20 complaints with NHTSA about the 2021 Hyundai Ioniq. The most-reported areas are Electrical system (11), Service brakes (5), Forward collision avoidance (5). That is close to the median of 31 complaints across the 6 Hyundai Ioniq model years in our data.
Used-buyer checklist for the 2021 Hyundai Ioniq
Based on where NHTSA recalls and owner complaints cluster for this model year, these are the areas worth checking before you buy:
- Electrical system (11 owner complaints) — Test every switch, window, light and warning lamp on a test drive, and ask about battery or alternator replacements.
- Brakes (5 owner complaints) — Brake firmly from speed and look for pulling, vibration or a soft pedal; ask for brake service history.
- Driver-assist sensors (5 owner complaints) — Check that driver-assist warning lights are off and sensors are clean and undamaged.
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
Hyundai models in our database average about 34 mpg (UK) combined on their most efficient configuration; the 2021 Hyundai Ioniq's 66 mpg is 32 mpg above that make average. Its 101 g/km CO₂ figure is 106 g/km lower than the 207 g/km Hyundai average.
Of the 6 Hyundai Ioniq model years we cover, the 2021 ranks 2nd for combined fuel economy on its best configuration (66 mpg UK combined, against a high of 70 mpg). See every Hyundai Ioniq 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 Hyundai Ioniq
Frequently Asked Questions
What engine does the 2021 Hyundai Ioniq 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 Hyundai Ioniq?
The most efficient configuration returns around 66 mpg (UK) combined, or 55 mpg on the US EPA cycle. Across all configurations the UK combined figure runs from 62 to 66 mpg.
How much does the 2021 Hyundai Ioniq cost to fuel per year?
The US EPA estimates about $1,200 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 Hyundai Ioniq have any recalls?
NHTSA lists no safety recall campaigns for the 2021 Hyundai Ioniq as of 6 October 2026. Recalls can be issued years after a model is sold, so it is still worth checking your own VIN.
What are the most common problems reported for the 2021 Hyundai Ioniq?
Among the 20 owner complaints filed with NHTSA, the most-reported areas are Electrical system (11 complaints), Service brakes (5 complaints), Forward collision avoidance (5 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 Hyundai Ioniq have?
EPA measures interior passenger volume at 96 cubic feet (about 2,718 litres) and luggage volume at 27 cubic feet (about 765 litres). These are US EPA interior-volume figures, which are measured differently from the UK boot-capacity numbers manufacturers quote.