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。
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.
