Every bookmaker builds a profit margin into their odds. We measured it across 140+ Australian bookmakers in August 2026. Here's what we found.
What Is a Margin?
A bookmaker margin (also called overround or vig) is the gap between the true probability of outcomes and the implied probabilities from the odds. A perfectly fair market has 100% implied probability. A market with a 5% margin has 105%. The extra 5% is the bookmaker's edge.
Lower margin = better value for you. Over hundreds of bets, even a 1% difference in margin compounds into a significant edge.
How We Measured It
We pulled head-to-head (moneyline) odds from every active Australian bookmaker on our feed for all AFL, NRL, NBA, and EPL matches in August 2026. For each match, we calculated the implied probability of each outcome and summed them. The excess over 100% is the margin.
We measured margins at three points: opening line (when markets first appeared), 24 hours before the match, and at kickoff. This shows how margins shift as money comes in.
The Results
AFL Head-to-Head Margins
| Bookmaker | Avg Margin | At Kickoff |
|---|---|---|
| Pinnacle | 2.1% | 1.8% |
| Betfair Exchange | 2.4% | 1.9% |
| BetRight | 3.8% | 3.5% |
| PickleBet | 4.1% | 3.8% |
| Sportsbet | 5.2% | 4.8% |
| Ladbrokes | 5.4% | 5.0% |
| Bet365 | 5.6% | 5.1% |
| TAB | 6.1% | 5.7% |
Key finding: The gap between the tightest book (Pinnacle at 2.1%) and the widest (TAB at 6.1%) is 4 percentage points. On a $100 bet, that's the difference between paying $2.10 in margin vs $6.10. Over a season of AFL betting, that adds up to hundreds of dollars.
NRL Head-to-Head Margins
NRL margins followed a similar pattern but were slightly wider across the board — averaging 0.3% higher than AFL. This likely reflects lower liquidity and fewer bets per match.
NBA Margins
NBA margins were tighter than both AFL and NRL, with Pinnacle averaging just 1.9%. This reflects the global liquidity of NBA markets — more money flowing in means sharper lines.
What This Means for You
- Line shop relentlessly. The difference between the best and worst price on the same outcome is often 3-5%. That's your edge.
- Use exchange pricing when possible. Betfair and Pinnacle consistently offer the tightest margins.
- Watch the margins shift. Margins tighten in the 24 hours before kickoff as smart money comes in. That's often the best time to bet.
- Track your own cost. If you're betting at TAB (6.1% margin), you need to win 53.3% of bets just to break even. At Pinnacle (2.1%), you only need 51.1%.
Methodology Notes
This report covers August 2026. Margins were measured on head-to-head (moneyline) markets only. Alternate lines, spreads, and player props typically carry higher margins. Data sourced from live bookmaker feeds. We'll publish this report monthly.
Next Month
We'll publish the September report in early October, covering the start of the AFL finals and NRL finals. Expect margins to tighten on high-stakes matches.
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David contributes long-form retrospectives, case studies, and operational pieces on AU advantage betting markets. His writing focuses on the realities of running a sustainable AU advantage operation — what works, what fails, and the operational details most blogs gloss over.