# Sports Betting — Quick Reference

## How it works

Read the event, selection, scoring period, accepted price and total stake. Check overtime, draws, participation, voids and pushes in the actual settlement terms. Compare total returns with all money spent.

## The key numbers

Three separate measures for stated −110 examples:

- **Break-even win rate:** 52.38% with equal stakes, no pushes and no other adjustments.
- **Expected net loss / stake:** 4.55%, only if the true win probability is 50%.
- **Two-price overround:** 4.76% for a complete mutually exclusive market priced −110 on both sides.

## One thing to know

A quote describes a payout, not a verified true probability. At −110, a winning $110 wager returns $210 total: $100 net winnings plus the stake. The exact decimal equivalent is 21/11, about 1.90909; 1.91 is a rounded comparison, not exactly the same quote.

## The math in plain English

Break-even solves `100p − 110(1 − p) = 0`. Assuming p is 50% instead gives $5 expected loss per $110 risked. Adding two converted −110 prices and subtracting 1 gives overround. Those calculations must not share one generic vig percentage.

Ten independent selections, each with true 50% probability, all win with probability 1 in 1,024. If their exact −110 decimal prices multiply with no other adjustments, the hypothetical ticket pays about $642.08 net per $1 on a win and has 37.2% expected loss per stake. Correlation, another quote or settlement changes require a new calculation.

Positive quoted overround does not guarantee realized sportsbook profit. A bettor's win rate also needs its stakes, prices and costs before it can establish profitability.

## Sources and scope

[DraftKings terms glossary](https://support.draftkings.com/dk/en-us/glossary-of-betting-terms?id=kb_article_view&sysparm_article=KB0010398) and [parlay explanation](https://support.draftkings.com/dk/en-us/what-is-a-parlay-bet?id=kb_article_view&sysparm_article=KB0010683), checked September 5, 2026, are named operator examples. All numerical exercises are explicitly hypothetical calculations, not event forecasts or product offers.

[Full Sports Betting guide](https://www.playbookrg.com/brand/content/games/sports-betting/) · Playbook RG · Free to copy and adapt under CC0. External sources have their own terms.