Betting Guide

Odds, explained

Sportsbooks quote odds in American format by default: a minus sign means the favorite and a plus sign means the underdog.

• -150 — you risk $150 to win $100.
• +200 — you risk $100 to win $200.
• Even money (-100 / +100) — you risk $100 to win $100.

The gap between the two sides is the book's margin (the "vig" or "juice"). Understanding the vig helps you see what the market thinks and where the price is moving.

The three main markets

Most games offer three core ways to bet, plus player props and alternate lines built on top of them.

• Moneyline — pick who wins the game outright. No points involved.
• Point spread — the favorite must win by more than the spread; the underdog can lose but "cover" by staying within it.
• Total (over/under) — bet on whether the combined score of both teams goes over or under the posted number.

Team totals, alternate spreads, and alternate totals are simply shifted versions of these numbers with different prices.

How parlays work

A parlay combines two or more individual bets (legs) into one wager. Every leg must win for the parlay to pay out — a single miss voids the whole ticket.

That's why parlays pay more: the prices multiply together, and the risk multiplies with them. A three-leg parlay at -110 each pays roughly +600, but hits far less often than any single leg.

• More legs means a larger payout and a lower chance of winning.
• Same-game parlays combine correlated legs — the books price that correlation in, which usually trims the value.
• Because one loss kills the ticket, many bettors keep parlays small and treat them as the higher-variance part of their approach.

The research value is in each leg: check whether the numbers behind every pick hold up before you stack them together.

Reading line movement

Lines are not static. Books adjust spreads, totals, and prices as injuries surface, weather rolls in, or money piles onto one side.

• Opening line — the first number posted, often softest in the first hours.
• Steam — a rapid move across many books, usually following sharp money.
• Reverse line movement — the line moves against the public side, a signal worth studying.

Comparing prices across several books ("line shopping") is one of the simplest edges available: a half point on a spread or ten cents on a total compounds over a season.

Player props and alt lines

Player props bet on individual stats — passing yards, points, rebounds, strikeouts — rather than the game outcome. Alternate lines let you shift any market: a higher over line pays more but is harder to hit, a lower one pays less but hits more often.

Props are where usage, matchups, and role changes matter most. Check minutes, snap counts, injury reports, and how a defense performs against that position — not just the posted number.

Bankroll management

Your bankroll is the money you have set aside strictly for betting — separate from rent, bills, and savings. Managing it is what keeps a losing week from ending your season.

• Units — size every bet as a percentage of your bankroll, commonly 1–2%. A unit is a measuring stick, not a feel.
• Flat staking — bet the same unit every time instead of chasing losses with bigger wagers.
• Variance — even well-researched bets lose. Stretches of losses are normal; the goal is surviving them intact.

Never bet money you can't afford to lose, and take a break if the losing streak stops feeling like variance.

Researching a bet

A bet is a research conclusion. Before you place one, walk through the same checklist the sharps do:

• Injury reports and late scratches
• Rest, travel, and schedule context
• Recent performance versus the specific matchup
• Weather and venue factors
• Where the line has moved since open — and why

OnlyParlays is an AI-assisted research tool built to speed this up. AI output can be inaccurate or outdated, so verify what it shows you, then make your own decision. We do not place wagers, and no outcome is promised.

Bet responsibly

Only bet where it is legal in your jurisdiction, and only wager what you can afford to lose. Set deposit and time limits before you start. If betting stops being fun, or starts feeling like a way to recover losses, step away and reach out for help — support resources are available in most states and countries.

See our Responsible Gambling page for more.