Ideally, you want a mat size that will fit in your house, as this can be used all year-round. However, you also need to consider how useful the size of the mat will be. Putting mats are typically around 9 feet in length, which is an average-sized green on real golf courses. Mats that are too small could hinder your approach, while mats that are too big could cause you to overhit the ball once you arrive at the real thing.\r