The Mazda3 Sedan measures 4,660 mm in length, 1,795 mm in width, and 1,440 mm in height, with a wheelbase of 2,725 mm. Rear passenger legroom and headroom are adequate, with a boot capacity of approximately 374 litres. The Mazda3 Fastback has a shorter body, but the rear seats can be folded flat to expand cargo capacity.
Mazda3 Sedan 車身長 4,660 mm、闊 1,795 mm、高 1,440 mm，軸距 2,725 mm。後排乘客嘅腿部空間同頭部空間都算充足，尾箱容積約 374 公升。Mazda3 Fastback 五門揭背版車身較短，但後排座椅可以放平擴充載物空間。
