This is a reversible hat. It was a gift from a friend, so I don't know the exact size because there's no tag. Please check the images for measurements when laid flat. I mainly used other hats, so I've only worn this a few times. I think it's around 40-42cm, but since there's no tag, I'm selling it at a low price, so please understand. It has been home-cleaned. I will fold it for shipping.