The odds of winning a toss coin is one is to one or 1/1 in fractional odds format. Coins usually have two sides (i.e., heads and tails), and every flip of a coin results in either a win or loss. Since there is one chance of winning and one chance of losing a coin toss, the odds of winning (or losing) a coin toss is, therefore: 1 / 1 =1/1, or one is to one. Read more