Introduced at the 2011 International Motor Show Germany as a subcompact executive car,[2] model years for the W246 started at 2012 and ranged to 2018.

[6] Seen as a taller and a more practical alternative to the Mercedes-Benz A-Class, the W246 was available in petrol, diesel, natural gas, and a battery electric variant.

Prigl had stated, “We will start with the B-Class and the MFA platform will contain an intellectual property solution that will allow us to produce both a direct, high-roof, high seating position replacement for the B-class.” Prigl had also mentioned that the MFA architecture was so versatile that it allowed the integration of a full cell stack, a battery pack, hydrogen tanks and compressed natural gas.

Although this nameplate never came to fruition, the 4.6 metre long Mercedes-Benz CLA subcompact executive sedan launched slightly after the B-Class.

Like the W176 A-Class which the B-Class shares its platform with, the W246 has MacPherson strut front suspension, while featuring a four-link setup at the rear.

[18] These features include: start/stop function which switches off the engine temporarily when the vehicle is stationary, alternator management for regenerative braking, and optimised tyres for rolling resistance which have low energy requirements while driving and also help to reduce fuel consumption.

The entry-level SE offers 16-inch alloy wheels, LED daytime running lamps, comfort suspension, cruise control, CD multimedia system, a reversing camera, 7-inch infotainment screen, USB ports with smartphone integration, air conditioning, adjustable boot floor, and man-made leather upholstery.

The AMG Line model features AMG-style front, side and rear aprons, 18-inch AMG-type alloy wheels with five double spokes, radiator grille, a dual exhaust system with trapezoidal stainless steel tailpipe trims, lowered suspension, perforated brake discs, artificial leather with contrasting red stitching, a multi-function steering wheel which is covered in leather and has red contrasting topstitching, a revised instrument cluster, and a sports pedal system and red contrasting topstitching and silver chrome.

[20][21] In July 2012, for the 2013 model year, Mercedes had added illuminated door sills and an auxiliary heater which had included a remote control as optional.

Both trim levels feature standard heated seats, an auto start/stop, a seven-speed dual clutch transmission, and a 2.0-litre turbo-cylinder making up to 208 horsepower and 258 lb-ft of torque.

[25] The B250 offers a wide selection of packages to choose from: The Versatility package adds a powered front driver's seat with powered lumbar support, with the addition of auto-dimming rearview and side mirrors, power-folding mirror controls, a universal garage door opener, and a storage system dubbed Easy Vario Plus that adds a flat-folding front passenger seat, fore and aft sliding rear seats, a height-adjustable cargo floor, and enhanced iPhone connectivity via Apple CarPlay.

The Premium Package adds a black fabric roof-liner and panoramic sunroof, dual-zone auto HVAC, a rearview camera, navigation, DVD player and blindspot assist.

Models started at the B180 which featured 16-inch, 10-spoke alloy wheels, six-speaker audio system, Bluetooth audio streaming, 14.7 cm TFT colour display, climate control air conditioning, cruise control, front and rear parking sensors, trip computer, 1/3 to 2/3 rear folding seats, and rains sensing wipers.

Finally, the B250 for Australia features 18-inch alloy wheels, lowered "Avantgarde" suspension, bi-xenon headlights with washers, and privacy glass.

It is one of the only B-Class models to ever be sold in the U.S. market, as well as being the first Mercedes-Benz vehicle to ever be offered in an electric variant, though it was only available in certain states that required ZEV mandates.

The United States Environmental Protection Agency (EPA), under its five-cycle testing, rated the 2014 B-Class Electric Drive with an all-electric range of 87 mi (140 km).

[36] The refreshed trims start at the Style model which features two louvres painted in "Iridium Silver" and additional chrome inserts around the car.

The interior features Vianen fabric on the seats, while the steering wheel, gear lever and dash switches are decorated with silver chrome accents.

[39] The variant tested was a black B200 CDI unit in left-hand drive form, which had a kerb weight of 1,475 kg (3,252 lb).