I receive a lot of pms regarding how odds work.
So here are some pointers.
Hope it helps.
Feel free to add better explanation, correction or useful info
American odds format
Example: Tigers -160, Jays +140 // over 8 runs -115, under 8 runs -105
The smaller the line, the more favored the team/proposition according to the odds maker / public perception
Negative lines
The amount of units the bettor needs to wager to win 100 units
From the above example, to get 100 from Det win, 160 need to be staked.
Putting 105 on the under will bring back 100 if successful
To calculate your winnings, divide your stake by the absolute value of the line, then multiply by 100
548 units wagered on Tigers @ -160 gets you 342.50 units
(548 / 160)*100 or 548/1.6
1000 on the over @ -115 = 1000/1.15 = 869.57
Positive lines
The amount of units the bettor gets for every 100 wagered
100 on Jays @ +140, brings back 140 units
Multiply the stake with the line value, then divide by 100
Stake of 400 on Jays @ +140 returns 560
(400*140)/100 or 400*1.4
Decimal odds format
Example: Team A @ 1.52, Team B @ 3.30
Decimal odds are always a positive number
Stake is included in the odds
If the odds value is > 1 and < 2, favored proposition is indicated
To get your winnings, multiply the amount wagered and the odds line, then take out the stake
or
Amount wagered multiplied by odds value less one
1000 on team A @ 1.52 gives you 520 units
(1000*1.52)-1000
or
1000*(1.52-1)
Other odds formats
Google