Every bet you will ever place starts with a number — something like +150 or −200. Those numbers are not random. They tell you two things at once: how much you stand to win, and how likely the sportsbook thinks the outcome is. Learn to read them and you’re no longer guessing; you’re making informed decisions. This first course covers nothing but odds and payouts, because everything else in betting is built on top of them.
What American odds actually mean
In the U.S., odds are quoted with a plus or minus sign in front of a number. The sign tells you which side is favored; the number tells you the size of the bet or the payout relative to $100.
- Negative odds (favorites) — e.g. −200 — show how much you must risk to win $100. At −200 you stake $200 to win $100.
- Positive odds (underdogs) — e.g. +150 — show how much you win on a $100 stake. At +150 a $100 bet wins $150.
The bigger the negative number, the heavier the favorite. The bigger the positive number, the longer the underdog. −500 is a strong favorite; +500 is a big long shot.
Worked example
The Lakers are −150 to beat the Suns at +130.
- Bet $150 on the Lakers → win $100 (total return $250).
- Bet $100 on the Suns → win $130 (total return $230).
You never have to bet exactly $100 or $150 — those are just the reference points. The ratio is what matters, and it scales to any stake.
From odds to a payout
To find profit on any stake, convert the odds into a simple multiplier.
The payout formulas
Positive odds: profit = stake × (odds ÷ 100) Negative odds: profit = stake × (100 ÷ |odds|)Total return = stake + profit.
So a $40 bet at +150 returns 40 × (150 ÷ 100) = $60 profit ($100 back). A $40 bet at −150 returns 40 × (100 ÷ 150) = $26.67 profit ($66.67 back). Same number, opposite sign, very different payout — which is exactly the point of the sign.
Decimal odds (and why they’re easier)
Most of the world — and most betting tools — use decimal odds. A decimal price is just your total return per $1 staked, so the math is effortless: return = stake × decimal odds.
Convert American → decimal
Positive: decimal = (odds ÷ 100) + 1 Negative: decimal = (100 ÷ |odds|) + 1| American | Decimal | $100 returns |
|---|---|---|
| +200 | 3.00 | $300 |
| +150 | 2.50 | $250 |
| −110 | 1.91 | $191 |
| −200 | 1.50 | $150 |
If a number ever confuses you in American format, convert it to decimal and the payout becomes obvious.
The hidden message: implied probability
Odds aren’t only a payout — they’re a probability in disguise. Every price implies how often the bet needs to win just to break even. This is the most important idea in the course, because finding bets where the real chance is better than the implied chance is the entire job of a sharp bettor (you’ll go deep on this in Course 07).
Convert odds → implied probability
Negative odds: |odds| ÷ (|odds| + 100) Positive odds: 100 ÷ (odds + 100)So −200 implies 200 ÷ 300 = 66.7%, and +150 implies 100 ÷ 250 = 40%. Notice those two numbers add up to 106.7%, not 100%. That extra 6.7% is the sportsbook’s built-in margin — the “vig” — and it’s the subject of Course 05.
Common mistakes
- Reading the number as dollars to bet. +150 doesn’t mean “bet $150.” It means win $150 per $100 risked.
- Confusing profit with total return. A winning −200 bet of $200 pays back $300 total — $100 of that is profit, $200 is your stake returned.
- Ignoring the implied probability. If you only look at the payout, you’ll happily take bad prices. The probability is the half that tells you whether the price is fair.
Key takeaways
- Minus = favorite (risk to win $100); plus = underdog (win on a $100 stake).
- Profit scales to any stake — the odds are just a ratio.
- Decimal odds make payouts trivial: return = stake × decimal.
- Every price hides an implied probability — that’s what you’ll learn to beat.