Sports betting consist of betting a sum of money in anticipation of the result of a sporting event.
When you make sports bet, your return is the amount of your bet multiplied by the odds associated with your prognosis.
The amount of money on your bet is called the "Stake".
The "odds" are the ratio of the full payout to the stake, in a decimal format. A small odd means that the prognosis has a strong chance of being realized and vice versa.
The actual profit is your return minus the original stake, it represents the amount of money made from the initial investment.
Let's take a simple example: You decide to bet on a football match between Barcelona and Arsenal. The bookmaker chooses Barcelona as the favourite. You then have three possibilities of bets rated differently:
Victory of Barcelona: 1.4
Draw: Listed at 4.2
Victory of Arsenal: 5.8
If for example, you bet 100$ on the victory of Barcelona at the "odds" of 1.4, your return on investment would be 100x1,4 = 140 €. Therefore your profit would be 40$. If, on the other hand, you bet the same amount of money on the victory of Arsenal, your potential gain is 100x4,2 = 420$. That is 320$ of real profit.
Of course, if your prognosis is wrong, you lose your entire bet.