In-depth reviews

BMW i8 Roadster (2018-2020) running costs

The i8 Roadster is on the pricey side, but the low running costs for a convertible sports car mean it should be affordable to keep on the road

Overall rating

4.0 out of 5

Running costs rating

4.0 out of 5

Insurance groupWarrantyService intervals2020/21 company-car tax cost (20%/40%)
503yrs / unlimited miles2yrs / 18,000 milesFrom £2,541 / £5,082

Shelling out more than £100,000 (when new) for any car is steep, but at least the BMW i8 Roadster does actually offer value for money in some key areas – especially when you consider it doesn’t really have any rivals. The plug-in petrol-electric technology wasn’t cheap to develop, while building cars from carbon-fibre is costly, too, so some of this cost is passed on to the customer.

There’s a 30-litre fuel tank as standard, which should give you a cruising range of 273 miles according to BMW’s figures. This will increase to 373 miles if you spec the optional 42-litre fuel tank, so add in another 33 miles thanks to that all-electric range boost and you’ll be looking at more than 400 miles between petrol fills and battery charges.

Squeeze the throttle into the carpet frequently and you won’t see anywhere near this range, but based on current petrol prices an annual fuel cost (12,000 miles) of around £1,500 based on our real-world economy figures is pretty good given the performance on offer and that its conventional petrol rivals would cost you double that.

Frequent charging helps keep your fuel bills even lower, while most average journeys shouldn’t exceed the zero-emissions range, so as long as you can plug in at your destination (driving between home and work, for example) then you might not need to fill up for months. The petrol engine is there to add flexibility and eradicate range anxiety for longer journeys or when you need it.

BMW i8 Roadster insurance group

Its high price and advanced technology mean the i8 falls into the highest insurance group (50), so it’ll be expensive to insure – but that’s no surprise given the desirability and performance, either.

It’s certainly no worse than other luxury models, and while premiums will depend on your circumstances (where you live, how many points you have on your licence and how long you’ve been driving) a quote in the region of £1,000 per year for a middle-aged driver with three points on their licence is reasonable.


It’s been years since the i8 went on sale in Coupe form, and as both cars use the same petrol engine and electric motor combination, the technology has proven reliable. There’s a three-year regular warranty included as well.


Servicing a pricey and technologically advanced car like this can be expensive, but with BMW’s Service Inclusive package was standard on all i8s and included servicing for three years/36,000 miles, based on 12,000-mile per year service intervals. As the car gets older, it'll be covered by BMW Value servicing plans for cars over three years old. 

BMW has 153 dealers across the UK, so you shouldn’t find yourself needing to travel too far when the i8 needs a service. It’s worth it, as a full main dealer service history should preserve its residual value on the used market.

Road tax

The i8 Roadster will cost just £10 to tax in its first year. However, road tax goes up after that, to £465 a year – this includes a £325 annual surcharge (for cars costing more than £40,000) on top of the £140 paid per year for an 'alternative-fuel vehicle' like this.

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