# Bookmaker margin calculator: how much does the bookie keep? > Free bookmaker margin calculator for Australian punters: enter decimal odds to see the overround, what the bookie keeps, the fair odds and which of two bookmakers pays more. - URL: https://safebet.ai/au/sports-betting/margin-calculator/ - Markdown version: https://safebet.ai/au/sports-betting/margin-calculator/index.html.md - Last updated: 2026-10-25 - Publisher: SafeBet.ai - Editorial policy and advertiser disclosure: https://safebet.ai/editorial-policy/ Australia · Sports betting · Free tool Enter a bookmaker’s odds on every outcome of a market to see how much it keeps, the fair odds with its margin removed, and, with a second bookmaker’s odds, which pays more on each outcome. By [SafeBet.ai Research Team](https://safebet.ai/editorial-policy/) Updated October 25, 2026 ## How the calculator works A bookmaker never offers fair odds. Add up the implied probabilities of every outcome in a market and you get more than 100%: the excess is the **overround**, and it’s how the bookmaker makes money whoever wins. At 1.90 on both sides of a line or total market, each side implies 52.6%, together 105.3%, and the bookmaker keeps about 5% of everything staked on that market over time. Enter the odds a bookmaker offers on each outcome, in decimal, fractional or American format, and the calculator shows how much it keeps, the share it pays back, and the fair odds with the margin removed. Add a second bookmaker’s odds on the same match to see which keeps less, and which pays more on each outcome. Betfair, Australia’s only licensed exchange, charges commission on winnings instead: compare it with our [Betfair commission calculator](https://safebet.ai/au/prediction-markets/commission-calculator/). ## Typical margins What a bookmaker keeps at common prices, computed with the same formula as the calculator. | Market and prices | Overround | Bookie keeps | Pays back | | ------------------------------------ | --------- | ------------ | --------- | | Line or total at 1.90 and 1.90 | 5.26% | 5.00% | 95.00% | | Head to head at 1.85 and 1.95 | 5.34% | 5.07% | 94.93% | | Head to head at 1.50 and 2.60 | 5.13% | 4.88% | 95.12% | | Soccer result at 2.10, 3.40 and 3.50 | 5.60% | 5.31% | 94.69% | | Soccer result at 2.25, 3.40 and 3.10 | 6.11% | 5.76% | 94.24% | [**Compare the 5 best sports betting sites in Australia** Ranked on regulation, fees, features and payouts · bet365, PointsBet, Sportsbet and more See the ranking](https://safebet.ai/au/sports-betting/) ## Frequently asked questions ### What is the overround? The amount by which a bookmaker’s implied probabilities add up to more than 100%. At 1.90 on both sides of a line market, each side implies 52.6%, together 105.3%, and the bookmaker keeps about 5% of everything staked on that market over time. ### How is what the bookie keeps calculated? Hold = 1 − 1 ÷ (sum of the implied probabilities), which is what the bookmaker keeps if bets follow the fair probabilities. The payout rate is the rest. The calculator removes the margin proportionally to get the fair odds. ### Does a lower margin mean I will win? No. It means you lose less on average. Even at a low margin, a punter who picks at random loses part of everything staked over time. ## Keep reading [Methodology · 5 min **How we rank betting sites in Australia** We only rank bookmakers licensed by an Australian state or territory and listed on ACMA's register of licensed interactive gambling providers. Each is scored from 0 to 10 on six weighted criteria, licensing and safety, markets and features, odds and limits, payments and payouts, app and experience, and support and responsible gambling, and the ranking follows the overall scores. Penalties and undertakings from ACMA, AUSTRAC and the state and territory regulators lower the licensing score; we judge odds on what each bookmaker publishes, because several bookmakers' terms forbid automated collection of their odds; and we don't list or score bonuses. Read](https://safebet.ai/au/sports-betting/how-we-rank/) [Guide · 8 min **Is sports betting legal in Australia? What the law allows, and the rules** Yes, with a bookmaker licensed by an Australian state or territory and listed on ACMA's register, if you're 18 or over: the register listed 213 licensed providers on October 21, 2026. The Interactive Gambling Act 2001 allows online bets on racing, on sport before it starts and on other events the regulators approve, such as elections, but bans online bets on a sporting event once it has started: in-play bets on sport are legal only by phone. Licensed bookmakers can't take credit cards or crypto, must honour BetStop, the national self-exclusion register, and must offer deposit limits and monthly statements. Online casinos and pokies are illegal. Read](https://safebet.ai/au/sports-betting/is-sports-betting-legal/) Researched and written by [SafeBet.ai Research Team](https://safebet.ai/editorial-policy/) · Betting analysts & data scientists The team behind SafeBet.ai’s AI sports picks: data analysts, AI engineers and sports bettors based in Maastricht. Since 2021 our models have analyzed 30,088 matches. We review betting, casino and prediction-market platforms against a published methodology and cite official sources for every fact. [Editorial policy](https://safebet.ai/editorial-policy/) [How we rank](https://safebet.ai/au/sports-betting/how-we-rank/) [About SafeBet.ai](https://safebet.ai/about/) [Report an error](https://safebet.ai/support/) 18+ Online sports betting is legal in Australia only with providers licensed by a state or territory and listed on ACMA’s register, for adults 18+. Online bets on an event that has already started aren’t allowed, and BetStop lets you exclude yourself from every licensed provider at once. Only play with money you can afford to lose. Gambling problem? Call [1800 858 858](tel:1800858858) (National Gambling Helpline, free and confidential, 24/7) or read our [responsible gambling guide](https://safebet.ai/au/guides/gambling-help-australia/). Top 5 sports betting sites · Australia 1. [1 **bet365** Best overall 9.1](https://safebet.ai/au/sports-betting/bet365-review/) 2. [2 **PointsBet** Withdrawals within 30 minutes 8.6](https://safebet.ai/au/sports-betting/pointsbet-review/) 3. [3 **Sportsbet** Most-rated app 8.4](https://safebet.ai/au/sports-betting/sportsbet-review/) 4. [4 **betr** Deposit and loss limits 8.0](https://safebet.ai/au/sports-betting/betr-review/) 5. [5 **Dabble** Biggest same-game multis 7.8](https://safebet.ai/au/sports-betting/dabble-review/) [Full ranking](https://safebet.ai/au/sports-betting/) Free sports betting site tools - [Gambling site legality check (Australia)](https://safebet.ai/au/sports-betting/licence-check/) - [Bookmaker margin calculator (Australia)](https://safebet.ai/au/sports-betting/margin-calculator/) Sports betting guides - [Is sports betting legal?](https://safebet.ai/au/sports-betting/is-sports-betting-legal/) - [How we rank bookmakers](https://safebet.ai/au/sports-betting/how-we-rank/)