HOW ODDS WORK
American odds function on a scale that uses 100 units as a base. The easiest way to view this is that everything is built around $100 wagers. To be clear, this does not mean that the player has to wager $100; it is merely designed as a ratio to explain the payout.
The odds are structured in a way that denotes a favorite (-) and an underdog (+). The easiest way to explain this is by using a few examples. Below you will see the American odds, their fractional counterpart and the resulting payout based on wagers of $100 and $5.
You’ll notice an additional number in brackets. When you make a bet, you lay down risk and your return is the combination of risk and winnings combined (payout = risk + winnings). That is because your original risk is being returned to you on top of your reward.