By clicking a retailer link you consent to third party cookies that track your onward journey. If you make a purchase, Which? will receive an affiliate commission which supports our mission to be the UK's consumer champion.

BMWi8 Roadster (2018-2020)

Used only
Sports
Plug-in hybrid (PHEV)

£64,066Typical price

Test score

where to buy or sell

The version of this car that we've reviewed might not be available to buy through all listed retailer links. For more options, see our guides on where to buy a car and how to sell a car.

Sign up to unlock the full expert review

The BMW i8 Roadster came some years after the coupé version introduced us to the idea of a supercar with a conscience. Here is a hi-tech, high-performance sports car, with the promise of extremely low running costs and emissions thanks to plug-in hybrid technology. Is it the driver's car of the future, or is it an ambitious reach too far? Find out in our full BMW i8 Roadster review.

pros

Content has been blurred out, please log in to view.

cons

What's included?

What is it?
What's it great at?
What's it like to drive?
How reliable are BMW plug-in hybrid cars?
How comfortable and spacious is it?
How economical is it to run?
How safe is it?
Is there anything I should look out for?
Should I buy it?

Full Access first month £5, then £10.99 per month, cancel at any time

KEY TEST RESULTS
Comfort and practicality
Brand reliability 0-4 years

Nov 2023Last checked by Which?
Feb 2019First reviewed by Which?
Jul 2018Released

The overall Which? test score is made up of the following star ratings, all determined by our rigorous lab tests.

How we test cars

19 Oct 2023

Ease of driving

Overall
Visibility
Smoothness of power delivery
Driving stability
Cabin layout

How we test ease of driving

To find out how easy a car is to drive, we assess cars across a number of areas from visibility and handling to the layout of the cabin and how smoothly the engine delivers its power.

Performance

Overall
In-gear acceleration
Brakes

How we test performance

We test braking distances and whether the effectivess of the brakes fade with repeat use. Performanc is based on in-gear acceleration.

Comfort and practicality

Overall
Entry and exit
Seat comfort
Ride quality
Quietness
Seat space
Boot space (small and sports cars)

How we test comfort and practicality

Comfort and practicality includes how easy it is, or not, to get in and out of the car and the maximum height of occupants. We also measure road, wind and engine noise and assess how well the car deals with bumps from large potholes to jittery surfaces like cobble stones.

Which? safety

Brand reliability 0-4 years

Overall
Electric car reliability
Plug-in hybrid reliability
Petrol reliability
Diesel reliability

How we test brand reliability 0-4 years

Our reliability ratings are based on the feedback from tens of thousands of UK motorists, as collected in our annual Which? car survey. We divide all reliability feedback into three age groups: cars aged up to four years, five to nine years, and 10 to 15 years.

Brand reliability 5-9 years

Overall
Plug-in hybrid reliability
Diesel reliability

Brand reliability 10-15 years

Overall
Petrol reliability
Diesel reliability

General
Class	Sports
Luxury	Yes
Convertible	Yes
Availability	Used only
Used price	£64,066 - £69,335
Fuel type	Plug-in hybrid (PHEV)
Tested fuel efficiency	52.2mpg
Length	4,689mm
Width (excluding wing mirrors)	1,942mm
Width (including wing mirrors)	2,225mm
Height	1,289mm
Driver max height
Boot space with seats up
Boot space with seats down
Number of seats	2
Folding rear seats	No
Isofix attachments	No
Turning circle	12.45 m
On sale date	30 July 2018
Lowest pence per mile cost	£23.16

Latest tested engine
Engine name	i8 Roadster
Fuel type	Plug-in-Petrol-Hybrid
Capacity and power	1.5-litre (374hp)
Transmission	6-speed automatic
Driven wheels	Four-wheel-drive (4WD)
Fuel tank capacity	30 litres
Tested fuel economy: City / Out of town / Motorway (mpg)
Tested fuel efficiency (mi/kWh)
Tested fuel economy: Combined (mpg)
Cost per mile	23.16p per mile
Cost of filling tank	£43
Monthly fuel cost
Annual fuel cost
NOx level	Very low
CO level	Medium
CO2 at tailpipe/tank-to-wheel (TTW) (g/km)	125
Well-to-wheel (WTW) CO2 (g/km)	185
Tested electric-only range (miles)	38 miles
Official fuel economy: NEDC	141.2
Official Euro emission level	Euro 6d-Temp
Engine test date	26 October 2018
Test programme	2017

Suggested Alternatives

Genesis

GV70 Electrified (2022-)

Available new
Medium/Large SUV
Electric

£65,105Typical price

Test score

Renault

Espace (2003-2012)

Used only
MPV
Petrol/Diesel/Mild hybrid

£750Typical price

Test score

Seat

Altea (2004-2015)

Used only
MPV
Petrol/Diesel/Mild hybrid

£1,011Typical price

Test score

How to find cheap car insurance
Find out ways to get cheaper car insurance quotes from price comparison sites and how to haggle with car insurance companies to save money
Best electric cars for 2024
Our independent lab tests reveal the best electric cars with enough range to go the distance.
How we test cars
Every car we review is subjected to hundreds of tests in our lab and on the road. Find out how our tests help you choose the best car, and avoid the worst.

All new and used car advice

BMWi8 Roadster (2018-2020)

where to buy or sell