Looking for a way to save space in the backseat of your vehicle? In an effort to assist families with multiple kids who struggle with the limited amount of space in their backseat, we have compiled a list of the most narrow car seats offered at EliteCarSeats.com. The following car seats listed below are among the narrowest booster seats, infant car seats, convertible car seats and toddler car seats we feature – measuring 17 inches wide or less. Keep in mind the measurements are taken at the base of the seat, and in some cases the seat back of the car seat may be wider than the base. Therefore, the seat base width may not always be the most accurate portrayal of how narrow the seat is.