# Booster seats that fit three across in one back seat Which booster seats fit three across in a single back seat? PEG / Peg Perego Primo Viaggio Flex 120: It is a go\-to narrow booster for tight three\-across setups because it is 14 inches at the seat bottom and 17 inches at its widest in narrow mode\. The booster is narrow and lacks armrests, so it fit the reviewer's tricky three\-across situation\. Diono Connect3 RXT: Diono says it fits three\-across and is less than 17 inches wide without sacrificing interior seat space\. A parent reports that a Diono backless booster fits in the middle between two Diono Radian 3R seats in a Subaru Forester with no fit issues, and that a similar setup also fit in a small Tesla and a RAV4\. PEG Perego Viaggio Flex 120: Its narrow footprint made a difficult three\-across situation work, and despite having no armrests the belt fit was consistently good across the vehicles and seating positions tried\. Britax UpNGo Click: The seat is 17\.1 inches wide and is designed to fit three across in most vehicles, but Britax will not guarantee 3\-across fitment in every vehicle\. ### 1. [PEG / Peg Perego Primo Viaggio Flex 120](/products/ucp/strolleria-com/3782284247114) (sold by strolleria\.com) It is a go\-to narrow booster for tight three\-across setups because it is 14 inches at the seat bottom and 17 inches at its widest in narrow mode\. - Width: It is a go\-to narrow booster for tight three\-across setups because it is 14 inches at the seat bottom and 17 inches at its widest in narrow mode\. (blog) - Three\-across evidence: The booster is narrow and lacks armrests, so it fit the reviewer's tricky three\-across situation\. (blog) - Height and weight limits: It is one of the tallest boosters on the market; the highest belt guide is 22 inches, with a 63\-inch height limit and 120\-pound weight limit, and no vehicle head restraint is needed\. (blog) ### 2. [Diono Connect3 RXT](/products/ucp/megababiesusa-com/8673372274942) (sold by megababiesusa\.com) A parent reports that a Diono backless booster fits in the middle between two Diono Radian 3R seats in a Subaru Forester with no fit issues, and that a similar setup also fit in a small Tesla and a RAV4\. - Width: Diono says it fits three\-across and is less than 17 inches wide without sacrificing interior seat space\. (listing) - Three\-across evidence: A parent reports that a Diono backless booster fits in the middle between two Diono Radian 3R seats in a Subaru Forester with no fit issues, and that a similar setup also fit in a small Tesla and a RAV4\. (review) - Height and weight limits: The manual states a weight range of 40–120 lb \(18–54 kg\) and a height range of 38–63 in \(97–160 cm\)\. (manual) ### 3. [PEG Perego Viaggio Flex 120](/products/ucp/albeebaby-com/9564437938407) (sold by albeebaby\.com) Its narrow footprint made a difficult three\-across situation work, and despite having no armrests the belt fit was consistently good across the vehicles and seating positions tried\. - Width: - - Three\-across evidence: Its narrow footprint made a difficult three\-across situation work, and despite having no armrests the belt fit was consistently good across the vehicles and seating positions tried\. (blog) - Height and weight limits: It is one of the tallest boosters available, with a highest belt guide at about 22 inches, so most children can use it until they no longer need any booster\. (blog) ### 4. [Britax UpNGo Click](/products/ucp/strolleria-com/8008999993418) (sold by strolleria\.com) The seat is 17\.1 inches wide and is designed to fit three across in most vehicles, but Britax will not guarantee 3\-across fitment in every vehicle\. - Width: The seat is 17\.1 inches wide and is designed to fit three across in most vehicles, but Britax will not guarantee 3\-across fitment in every vehicle\. (listing) - Three\-across evidence: The seat is 17\.1 inches wide and is designed to fit three across in most vehicles, but Britax will not guarantee 3\-across fitment in every vehicle\. (listing) - Height and weight limits: The UpNGo Click is designed for children from 40 to 120 lb and 46 to 63 inches tall\. (listing) Every value in the table is a fact RoboTrunk checked, linked to the page it came from\. A dash means no checked fact fills that cell\. Prices and stock change, so this page prints neither: each product name links to its RoboTrunk page, which shows them live\. 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