Two basic types of boxing bets are Fight Result and Total Rounds o/u.

1 X 2 Fight Result

Example:
Floyd Mayweather Jr: 1.57
Draw: 21
Ricky Hatton: 2.25

In this example, Floyd Mayweather is the favorite while Hatton is the underdog. A $100 bet on Mayweather will win $57. While a $100 bet on Hatton will win $125. A $100  bet on Draw will win $2000. If the result is a draw, bets on Hatton and Mayweather will lose.

1  2  Fight Result (Draw no Bet)

Example:
Floyd Mayweather Jr: 1.48
Ricky Hatton: 2.87

In this example, Floyd Mayweather is the favorite while Hatton is the underdog. A $100 bet on Mayweather will win $48. A $100 bet on Hatton will win $187. If the result is draw, bets on Hatton and Mayweather will be refunded.

Total Rounds O/U

Over 11.5 rounds: 1.398
Under 11.5 rounds: 3.310

11.5 rounds would be one minute and thirty seconds of the 12th round. If Mayweather is knocked out more than halfway through 12th round, all bets on the Over would be considered winners.

As a general rule, a boxing match is declared official after the bell starting the first round has rung.