Sports betting · Beginner’s guide
How to Bet on Sports — Moneyline, Spread & Totals Explained
Sports betting has exactly three core markets — moneyline, spread and totals — and everything else on the board is a variation of those. Learn the math behind the three and you can read any board at any of the best sports betting apps. Here’s the whole thing, with real numbers, from someone who used to post those numbers for a living.
By Jake Mercer, ex-sportsbook trader — Updated August 2026. 21+.
Moneyline: pick the winner, read the price
A moneyline bet is a straight pick: who wins the game. The American odds format tells you the price of that pick:
- Favorite: Bills -150. You risk $150 to win $100. The minus number is what you must stake to win $100.
- Underdog: Dolphins +130. You win $130 for every $100 staked. The plus number is the profit on a $100 bet.
Convert those prices to implied probability and you can see the book’s take with your own eyes. -150 implies a 60% chance (150 ÷ 250); +130 implies 43.5% (100 ÷ 230). Add them: 103.5%. That extra 3.5% over a fair 100% is the vig — the margin you’re paying on every single bet. Your job as a bettor is to find numbers where the true probability beats the implied one. Nobody does that on every game; the people who make money at this do it a few percent of the time, at scale, with discipline.
| American odds | Implied probability | $100 bet returns |
|---|---|---|
| -200 | 66.7% | $150 ($50 profit) |
| -150 | 60.0% | $166.67 ($66.67 profit) |
| -110 | 52.4% | $190.91 ($90.91 profit) |
| +100 | 50.0% | $200 ($100 profit) |
| +130 | 43.5% | $230 ($130 profit) |
| +200 | 33.3% | $300 ($200 profit) |
Point spread: the great equalizer
The spread handicaps the favorite so both sides price near even, usually -110 each way. Example: Chiefs -6.5 (-110) vs. Broncos +6.5 (-110).
- Chiefs -6.5 wins if Kansas City wins by 7 or more.
- Broncos +6.5 wins if Denver wins outright or loses by 6 or fewer.
- The half-point (the “hook”) eliminates the tie. On whole numbers like -7, an exact 7-point margin is a push — stake refunded, nobody wins.
At -110, you need to win 52.38% of your spread bets just to break even. Tattoo that number on your brain: 52.4%. Win 54% over a meaningful sample — say 500+ bets — and you’re a genuinely profitable bettor, which almost nobody sustains. That’s not pessimism; that’s the arithmetic of the vig.
Key numbers: why 3 and 7 run the NFL board
NFL games land on a margin of 3 about 15% of the time and on 7 about 9% — field goals and touchdowns, that’s it. So the difference between -2.5 and -3.5 is enormous (you cross the single most common margin in the sport), while -6.5 vs. -7.5 matters far less. When I was on the desk, moving a line off the 3 was a decision; moving off 4 or 5 was housekeeping. As a bettor: pay for the hook around 3 and 7, ignore it everywhere else.
Totals (over/under): the third pillar
Bet whether the combined score goes over or under a posted number — say Celtics vs. Knicks, total 224.5 (-110/-110). You’re betting game environment, not the winner: pace, shooting variance, rest days, weather in outdoor sports, even referee tendencies in the NBA.
One honest market note: casual money overwhelmingly bets the over because high scores are more fun to root for. Books know this and shade totals slightly upward in high-profile games. That doesn’t make the under a free lunch — it makes it a small structural lean worth knowing about, especially in primetime spots where recreational volume is heaviest.
The vig, in one table
| Price (both sides) | Break-even win rate | Book hold |
|---|---|---|
| -105 / -105 | 51.2% | ~2.4% |
| -110 / -110 | 52.4% | ~4.8% |
| -115 / -115 | 53.5% | ~7.0% |
| -120 / -120 | 54.5% | ~9.1% |
This is why line shopping isn’t optional. Betting -105 instead of -110 is the difference between needing 51.2% and 52.4% winners to break even — over a 500-bet season, that 1.2-point gap is the entire ballgame. It costs you nothing but a second app on your phone.
Parlays: understand the tax before you buy the ticket
A parlay chains bets together — all legs must win or the ticket dies. A 3-leg parlay of -110 picks pays about +595, but the true odds of hitting three independent coin-flips-with-juice are +700. The book pockets that difference, and the tax grows with every leg you add: a 4-legger pays roughly +1228 against true odds of +1500.
| Legs (all -110) | Book pays | True odds | Hidden tax |
|---|---|---|---|
| 2 | +264 | +300 | ~9% |
| 3 | +595 | +700 | ~13% |
| 4 | +1228 | +1500 | ~16% |
Parlays are entertainment products — the book’s highest-margin mainstream bet. If you play them, play them small and know what you’re paying. For the full definition and why the payout math is stacked against you, read what a parlay bet actually is before building one.
And if your office runs a squares pool every February, that’s its own mini-game with fixed payouts and zero skill — here’s how football squares work, rules and all.
Where you can legally do this
As of August 2026, sports betting is legal in some form in 38 states plus DC and Puerto Rico — Missouri was the most recent launch, going live in December 2025. Notable holdouts include Texas, California and Georgia, where no licensed sportsbook operates; if you’re betting from those states on an app that claims otherwise, you’re on an offshore site with zero legal protection. Always confirm your state’s status before your first deposit.
38 states + DC live TX / CA / GA: not legal
Bankroll: the part that actually determines if you survive
- Set a roll you can lose entirely. If losing it changes your month, it’s too big. This is entertainment money, not rent money.
- One unit = 1–2% of that roll. $1,000 roll → $10–20 standard bet. Flat stakes, no doubling after losses, no “confidence multipliers.”
- Track every bet. League, market, price, result. If you won’t write it down, you’re gambling blind — and you’ll misremember your record in your own favor. Everyone does.
- Never chase. The tilt bet at worse odds to “get even” is how rolls die. Tomorrow’s slate always exists.
That’s the complete foundation: three markets, one vig table, one bankroll rule set. Everything else on this site — calculators, sport-specific picks, book reviews — builds on these numbers and nothing else.
FAQ — betting basics
What is the easiest bet for a beginner?
The moneyline. Pick the winner, know the price, done. It’s the cleanest way to learn how odds translate to probability before you add the spread’s margin math on top.
What does -110 mean in plain English?
Risk $110 to win $100. It’s the standard price on spread and total bets, and it means you must win 52.38% of the time just to break even. The $10 gap is the book’s margin — the vig.
How much should a beginner bet per game?
1–2% of a bankroll you can afford to lose completely. If that’s $10, bet $10. Small stakes aren’t a compromise — they’re how you stay alive long enough to actually learn.
What is a push?
A tie against the number — e.g. you bet Chiefs -7 and they win by exactly 7. Your stake is refunded, no win, no loss. Half-point lines (the hook) exist specifically to eliminate pushes.
Is sports betting legal where I live?
Probably, but check: 38 states plus DC have legalized it in some form as of August 2026, with Missouri the newest live market (December 2025). Texas, California and Georgia remain the big holdouts. Only bet with books licensed in your state.
Can I make a living betting sports?
Almost certainly not. Even professionals win only 53–57% of spread bets and grind thin margins at high volume. Treat betting as paid entertainment with a chance to win — the moment it’s income you need, the math is working against you.
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