2021 BMW 4 Series 2.0 420i M Sport

Overview

• Make: BMW
• Model: 4 Series
• Trim: M Sport
• Version: 2.0 420i M Sport Auto RWD Euro 6 (s/s) 2dr (181 bhp)
• Year: 2021
• Mileage: 52,935 miles
• Fuel: Petrol
• Body: Convertible, 2 doors, 4 seats
• Engine: 2.0 litres, 181 bhp
• Gearbox: Automatic
• Drive: Rear-wheel drive
• Colour: Black
• CO2: 160 g/km
• Emissions standard: Euro 6, ULEZ compliant

About this car

At 52,935 miles, this 2021 BMW 4 Series M Sport has covered about 8,900 more miles than other 2021 BMW 4 Series cars. Its asking price of £23,990 is £1,455 above the AskCar estimate of £22,535. The AskCar estimate uses UK dealer asking prices, including 1,826 BMW 4 Series adverts, and accounts for the car’s age, mileage and specification. We first saw this car advertised 33 days ago. Its asking price has since fallen by £409. According to the government's MOT record, its advertised mileage is consistent with the latest test. The seller is Williams Bolton Bmw, based in Bolton. How to contact the dealer and its opening hours are on this AskCar page.

Stock data as of 6 November 2026.

How we estimate prices and check cars

Price

Fair price: £1,455 (6%) over the AskCar estimate of £22,535.

The AskCar estimate is our expected asking price for this car. It uses UK dealer asking prices, accounting for make, model, trim, version, age, mileage, fuel, gearbox, body type, driven wheels, engine size and power. It is an advertised price, not a confirmed sale price.

It draws on 1,826 priced BMW 4 Series adverts across different ages and specifications, as of 6 November 2026.

A 2021 BMW 4 Series with the 2.0 petrol engine is typically advertised at £23,800: the median of the 148 for sale on AskCar, as of 6 November 2026.

Time on sale

This 2021 BMW 4 Series has been on sale for at least 33 days.

Price history

AskCar first saw this advert on 4 October 2026 at £24,399. Its asking price is now £23,990, £409 less. The latest price cut was seen on 8 October 2026.

Price changes recorded:

• 4 October 2026: £24,399
• 8 October 2026: £23,990

Mileage and MOT

MOT, from the government's MOT records (DVSA, the Driver and Vehicle Standards Agency), as of 6 November 2026: valid until 11 August 2027.

It failed its MOT on 6 August 2026 (front windscreen washer provides insufficient washer liquid) and passed 6 days later, on 12 August 2026.

There were no advisories at the latest test.

Mileage at that test: 51,832 miles, which matches the advertised 52,935 miles.

Advertised mileage is about 8,900 miles higher than the median mileage of a 2021 BMW 4 Series on AskCar.

Similar cars

26 other 2021 BMW 4 Series M Sport 2.0 petrol automatic convertibles are for sale at UK dealers, from £18,990 to £33,950, as of 6 November 2026.

The 3 closest to this car in mileage:

• 2021 BMW 4 Series M Sport, 2.0 petrol convertible, white. Mileage: 58,093 miles. Price: £21,025, £2,965 less than this car. Dealer: Carbase Bristol in Bristol. AskCar page: https://askcar.co.uk/car/bmw-4-series-2021-52eb4cdc01ce
• 2021 BMW 4 Series M Sport, 2.0 petrol convertible, white. Mileage: 58,943 miles. Price: £22,990, £1,000 less than this car. Dealer: Group 1 Southend BMW in Southend-on-Sea. AskCar page: https://askcar.co.uk/car/bmw-4-series-2021-088e831a7c9e
• 2021 BMW 4 Series M Sport, 2.0 petrol convertible, black. Mileage: 43,305 miles. Price: £24,000, the same price as this car. Dealer: MB Brent Park in London. AskCar page: https://askcar.co.uk/car/bmw-4-series-2021-fb7d7a051e27

• The nearest: 2021 BMW 4 Series M Sport, 2.0 petrol convertible, white, 10 miles from this car. Mileage: 35,008 miles. Price: £25,990, £2,000 more than this car. Dealer: Alpha Motors in Wigan. AskCar page: https://askcar.co.uk/car/bmw-4-series-2021-dfd9ebfe4c58