How much do you have to weigh to sit in the back of a car without a car seat?

In general, laws and safety guidelines vary by location, but many recommend that children be at least 4 feet 9 inches tall and weigh around 80 pounds before they can safely sit in the back seat without a booster or car seat. Additionally, it's important that they can properly use the seatbelt without it being too loose or improperly positioned. Always check local regulations and prioritize safety when deciding on car seat usage.