How American Odds Actually Work: −110, +250, and Why the Juice Matters
Every line on the board is telling you two things — the payout and the implied probability. Learn to read both in five minutes.
By Nolan Gaffney · Founder, LeagueLocks · Aug 10, 2026 · 6 min read
American odds look cryptic until someone tells you the one rule: the number is always about $100. A minus number is how much you must risk to win $100. A plus number is how much you win if you risk $100. That's it — everything else is arithmetic.
So −110 means risking $110 to win $100 (total return $210). +250 means risking $100 to win $250 (total return $350). Your league's $20 weekly bet at −110 returns $38.18 on a win; at +250 it returns $70.
Why favorites are minus and underdogs are plus
The sign encodes who's expected to win. Favorites carry minus numbers — you risk more to win less because the outcome is likelier. Underdogs carry plus numbers — you risk less to win more because the book thinks it probably won't happen. A pick'em game sits near −110 on both sides.
The juice (and why it's never a fair coin)
If a spread bet were a true 50/50, fair odds would be +100 on both sides. Books list −110 instead. That extra 10 is the juice (or vig) — the book's built-in fee. Bet both sides of a −110/−110 game with $110 each and you're guaranteed to lose $10. It's why 'just pick winners' isn't enough: at −110 you need to win 52.4% of your spread bets just to break even.
Implied probability in one formula
Minus odds: probability = odds ÷ (odds + 100). So −110 implies 52.4%, −200 implies 66.7%. Plus odds: probability = 100 ÷ (odds + 100). So +250 implies 28.6%. Add both sides of a game and you'll get more than 100% — that overage is the juice again, viewed from a different angle.
What this means for your league's weekly pick
When your crew debates a −350 moneyline favorite versus a +140 underdog spread, you're really debating implied probability versus payout. The −350 favorite must win 77.8% of the time just to be a break-even bet. The question to ask in chat isn't 'will they win?' — it's 'do they win more often than the number says?' That's the whole game.
Play responsibly. Betting should be entertainment between friends — if it stops being fun, call or text 1-800-GAMBLER.
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