Learn how sports betting works — sportsbooks, odds, bet types, and how the house makes money. Drew Tabor explains it clearly so you can bet smarter.
Most people who've never bet on sports assume it's complicated. It isn't. The basics take about ten minutes to understand, and once you do, you'll also see something the industry hopes you won't: the math is tilted against you — unless you know how to play it differently.
This guide covers everything you need to know about how sports betting works: what sportsbooks are, how odds work, what you can bet on, and how the house makes money on every single wager. By the end, you'll understand the system well enough to use it to your advantage rather than donate to it.
Table of Contents:
A sportsbook is a company that accepts bets on sports. They set the odds, take your wager, and pay you out if you win. That's the whole job.
In the pre-2018 era, this meant physical casinos in Las Vegas or illegal bookies operating out of the back of whatever establishment would have them. Today it mostly means an app on your phone. FanDuel, DraftKings, BetMGM, Caesars — these are all sportsbooks operating legally in the states that allow it.
Yes, as long as you stick to legally regulated sportsbooks in states that have legalized betting.
Legal sportsbooks are licensed by state gaming commissions and subject to strict financial oversight. Your money sits in segregated accounts — if FanDuel goes bankrupt tomorrow, your balance is protected. You also have legal recourse if there's a dispute. The state regulator can investigate and force resolution.
The major operators — FanDuel, DraftKings, BetMGM, Caesars — are publicly traded or owned by large casino companies with billions in revenue. They're not stealing your $500.
The danger is offshore sportsbooks. Books based in Costa Rica, Curacao, or Malta look legitimate but operate outside U.S. law. No consumer protections. No accountability. Some are fine, many aren't. If something goes wrong, you have no legal recourse.
The rule: if it's licensed in your state, it's safe. If it's not, you're taking a risk.
Odds do two things: they tell you how likely something is to happen, and they tell you how much you'd win if you bet on it.
In the U.S., odds use the American Odds format — a plus or minus sign followed by a number.
Negative odds (like -150) mean the bet is a favorite. The number tells you how much you need to risk to win $100. At -150, you bet $150 to win $100. If you win, you get $250 back (your $150 stake plus $100 profit).
Positive odds (like +200) mean the underdog. The number tells you how much you'd win on a $100 bet. At +200, you bet $100 to win $200. If you win, you get $300 back.
Even odds (+100) mean a pure 50/50 proposition — bet $100, win $100.
You don't have to bet $100. That's just the reference point. Bet $50 at +200 and you'd win $100. Bet $30 at -150 and you'd win $20. The math scales.
Odds expressed as a percentage are called implied probability. +200 odds imply a 33.3% chance of winning. -200 implies 66.7%. This is how the sportsbook tells you what they think the chances are for each outcome.
The key insight: if you think a team is 50% likely to win but the sportsbook is offering +120 (implying 45.5%), that's a bet worth making. If they're offering -140 (implying 58.3%), you'd be paying for odds that overstate the true probability.
The simplest bet in sports: pick who wins the game. If the Chiefs are -180 against the Broncos at +155, you think the Chiefs win, you bet -180 (risk $180 to win $100). Done. No points, no spreads — just who wins.
Moneylines work for any sport but are especially common in baseball and hockey, where scoring is low and a single run or goal matters more than margin.
A spread bet levels the playing field by giving the underdog a head start in points. If the Chiefs are -7.5, they need to win by 8 or more for a bet on them to pay off. Bet the Broncos +7.5 and they can lose by up to 7 and your bet still wins.
Spread bets are designed to be 50/50, so both sides typically price at around -110. Most football and basketball betting revolves around spreads because points matter.
A totals bet isn't about who wins — it's about how many total points both teams score combined. The sportsbook sets a number (say, 47.5 for an NFL game), and you bet whether the combined final score goes over or under that.
Like spreads, totals usually price at -110 on both sides. Weather, injuries, pace of play, and team styles all influence where the total is set.
A parlay bundles multiple bets into one. All your picks have to win for the parlay to pay. Lose even one, and the whole thing is dead.
The appeal is the bigger payout — combining three -110 bets into a parlay pays roughly +600, instead of the three separate smaller wins. The downside is the sportsbook charges vig on every leg, so the math works against you more than on a single bet. Recreational bettors love parlays. Sharp bettors know better — unless they're using them strategically.
Same-game parlays combine multiple outcomes from a single game: team to win, total to go over, and a specific player to score a touchdown, all in one bet. Currently the most-marketed bet type in the U.S. Sportsbooks push SGPs heavily because they're even more profitable for the house than regular parlays.
Prop bets (short for propositions) are wagers on outcomes not tied to the final score. Stephen Curry hitting at least four three-pointers. Travis Kelce catching a touchdown. A game going to overtime. The number of markets here is enormous and growing.
Here's the part the sportsbooks don't advertise.
On a standard 50/50 bet, both sides are typically priced at -110. You risk $110 to win $100. If the sportsbook takes equal action on both sides, they pay the winners using the losers' money — and pocket the leftover $10 per side as their cut.
That cut is called the vig (also called juice). It's built into every bet. Even on a "fair" 50/50 coin flip, you'd need to win 52.4% of your -110 bets just to break even. Below that, you're slowly bleeding money to the house.
This is why "the house always wins" is mostly true. Most bettors don't beat the vig consistently. They make emotional decisions, bet their favorite teams, chase parlays — and slowly donate to FanDuel's quarterly earnings.
The good news: unlike casino games with fixed house edges, sports betting isn't mathematically unbeatable. Smart money — specifically hedging — can flip the equation entirely.
The Ungambled app calculates this automatically — you don't have to do the math manually. See how it works →
Every bettor falls somewhere on this spectrum.
Squares are recreational bettors — casual fans betting for fun. They bet on favorite teams, chase big parlays, and make decisions based on emotion or gut. About 98% of bettors are squares. They're the engine that keeps sportsbooks profitable.
Sharps are professional or serious bettors who treat it like an investment. They use data, models, and research to find edges. They shop for the best odds, manage bankroll carefully, and focus on long-term profit over short-term excitement. Sportsbooks don't like sharps because sharps win in the long run — which means the sportsbook loses.
Whales are high-volume bettors wagering tens of thousands to millions annually. Most are wealthy squares betting for entertainment. Sportsbooks love square whales — they generate enormous revenue and get VIP treatment as a result.
Where do you want to be? The answer isn't automatically "sharp." Knowing how the system works lets you choose — and if you're hedging rather than trying to beat the house on skill, you can profit whether your analysis is good or not.
Here's how sports betting actually plays out when you use it intelligently — not gambling, but hedging.
The setup: FanDuel gave you a $200 bonus bet after signing up. You need to use it to bet or it expires.
Step 1: Find a large underdog with good odds. The Golden State Warriors are playing the Oklahoma City Thunder. The Warriors are +250 at FanDuel.
Step 2: Bet the $200 bonus on Warriors +250. If they win, you get $500 (the $200 stake is forfeited because it's a bonus bet, so profit = $500).
Step 3: At DraftKings, bet $380 in real cash on the Thunder -300. If the Thunder win, you collect $127 in profit ($380 × 100/300 = $127).
The outcome either way:
You locked in roughly $120–$127 no matter who wins the game. That's hedging a bonus bet. You're not gambling — you're running math.
I see this constantly. New bettors discover parlays, love the big payouts, and start making 6-leg parlays their bread and butter. The math is brutal — the vig stacks with every leg, and the sportsbook's expected profit on a 6-leg parlay is far worse for you than six individual bets. Parlays are a recreational tool. Use them strategically (for account profiling purposes, or when a parlay bonus makes the math work), not as your default bet.
Odds vary across sportsbooks. Significantly. If you're betting the Lakers moneyline at +120 at one book when DraftKings is offering +145 for the same bet, you're leaving money on the table. Serious bettors have accounts at multiple books and always check prices before betting. The spread between books is also where hedging opportunities live.
People see "bet $110, win $100" and think "that's basically even." It's not. That 9% effective vig compounds across hundreds of bets. At -110 on both sides, the sportsbook keeps roughly 4.5% of all money wagered. Run a million dollars through those -110 bets over a year and you've donated $45,000 to the house before a single bad pick. Track the vig on everything you bet.
Most new bettors sign up, collect the signup bonus, win a little, and immediately withdraw. This flags you as a bonus abuser. Sportsbooks stop sending bonuses to accounts that look like they were opened just to collect promotional money. The real profit is in staying active, playing the long game, and using account profiling tactics to maximize how long — and how valuable — your bonus flow stays.
Legal online sports betting is now available in more than 38 states (verify current count before publishing). The market generated over $11 billion in revenue in 2023, and mobile betting accounts for roughly 90% of all wagers in states that allow it.
The biggest players — FanDuel and DraftKings — control about 80% of the U.S. online market combined. But the list of legal operators is growing, and the bonus wars between books show no signs of slowing down.
For hedgers, this is the golden window. More legal sportsbooks means more accounts to open, more signup bonuses to hedge, and more arbitrage opportunities across different books. The math gets better the more options you have.
Sports betting is simple to understand and easy to use badly. The vig is real, parlays are the house's best friend, and most bettors lose money over time — not because they're unlucky, but because they're fighting the math.
Understanding how it works is step one. Using bonuses, hedges, and multiple sportsbook accounts to flip that math in your favor is step two. That's exactly what Ungambled is built for.
Ready to put this into practice?
The Ungambled app does the hedge calculation for you — it shows you exactly how much to bet on each side to lock in a guaranteed profit. No spreadsheet required.
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