What is the difference between a 200×200 and a 180×200 mattress?

The difference is 20 centimetres in width. On a 200×200 mattress, each sleeper has 100 centimetres of personal space, compared to 90 centimetres on a 180×200. That extra width makes a noticeable difference for couples who move around a lot during the night or who simply want a more spacious feel. A 200×200 also requires a larger bedroom and a matching 200×200 bed frame. If your room allows for it, the 200×200 is the most comfortable option for two people sleeping together on a single mattress.