How Betting Lines Work
Every odds number tells you two things: how much you win, and how likely the sportsbook thinks it is.
The Basics
-110
Favorite (negative odds)
You risk more than you win. Bet $110 to win $100. The minus sign means "you need this team to win to profit."
+150
Underdog (positive odds)
You win more than you risk. Bet $100 to win $150. The plus sign means "this team is not expected to win."
Payout Formula
Negative odds (favorite):
Profit = Units × (100 / |odds|)
e.g. 1u at -200 → win 0.50u
Positive odds (underdog):
Profit = Units × (odds / 100)
e.g. 1u at +200 → win 2.00u
Quick Reference
| Odds | Payout (1u bet) | Implied Prob |
|---|---|---|
| -110 | Bet $110 → win $100 | 52.4% |
| -150 | Bet $150 → win $100 | 60.0% |
| -200 | Bet $200 → win $100 | 66.7% |
| +150 | Bet $100 → win $150 | 40.0% |
| +300 | Bet $100 → win $300 | 25.0% |
Implied Probability by Odds
Sportsbooks bake in a small margin ("the vig"), so implied probabilities across both sides of a bet add up to slightly over 100%. The chart below shows what each line implies.
The Vig (House Edge)
Notice that a standard -110/-110 line means both sides have a 52.4% implied probability — adding up to 104.8%, not 100%. That extra 4.8% is the sportsbook's cut, called the vig or "juice." To break even at -110, you need to win 52.4% of your bets — not just 50%. This is why Pickem tracks your units won/lost rather than just win percentage.
Run Line / Point Spread
A spread bet levels the playing field. In MLB, the run line is always ±1.5 runs. If you take the favorite at -1.5 (-175), they must win by 2+ runs. If you take the underdog at +1.5 (+145), they can lose by 1 and you still win. Spread bets usually offer better underdog odds in exchange for the cushion.