What happens if the over/under is exact?

This rarely happens. Bookmakers usually offer over/under limits of 1.5, 2.5, 3.5, 4.5 etc. The .5 part enables all bets to have a definitive winning or losing outcome. However, bookmakers also sometimes provide limits of 1, 2, 3, 4 and more goals. In this situation, an exact over/under bet means that your stake will be refunded.