How Betting Odds Work

Decimal odds: the format used across Australian bookmakers

Every licensed Australian corporate bookmaker — bet365, Sportsbet, Ladbrokes, TAB, Neds, Unibet, PointsBet and others — displays prices as decimal odds by default. The number is your total return per $1 staked, stake included.

• Odds of 2.00 = even money. A $10 bet returns $20 ($10 profit).
• Odds of 1.50 = short price (likely favourite). A $10 bet returns $15 ($5 profit).
• Odds of 5.00 = longer price (outsider). A $10 bet returns $50 ($40 profit).

The formula never changes: Total return = stake × decimal odds. Profit = stake × (decimal odds − 1). Because your stake is already baked into the number, you don't have to add it back afterwards — which is why decimal odds are the easiest format for quickly checking what a bet is worth.

Turning odds into implied probability

Decimal odds also encode a probability. Divide 1 by the odds and you get the implied probability the bookmaker has assigned:

- Implied probability = 1 ÷ decimal odds.

So odds of 2.00 imply 1 ÷ 2.00 = 0.50, or a 50% chance. Odds of 1.25 imply 80%. Odds of 4.00 imply 25%.

This is the single most useful calculation for a bettor. If you think a team in an A-League match has a genuine 60% chance of winning but it's priced at 2.20 (implied 45.5%), the bookmaker rates that outcome as less likely than you do — which is exactly the situation you're hunting for. Comparing your own estimate against the implied probability is the foundation of finding value, whether you're betting the AFL, NRL, Big Bash or an ATP Tour match.

The bookmaker margin (overround) — why probabilities add up to more than 100%

Add up the implied probabilities of every outcome in a market and you won't get 100%. You'll get more. That extra slice is the bookmaker's margin — often called the overround or the "vig".

Take a two-way market (say, a tennis match with no draw) priced at 1.90 / 1.90:

• Player A: 1 ÷ 1.90 = 52.6%
• Player B: 1 ÷ 1.90 = 52.6%
• Total = 105.2%

That 5.2% above 100% is the margin. In a fair, margin-free market both players would be 2.00. The tighter the total is to 100%, the better the value for you.

Our odds sampling gives a concrete read on this. Across the markets we sampled, Sportsbet showed the lowest average margin at roughly 4.9%, while bet365 sat highest among the sampled operators at about 7.4%. Ladbrokes (~5.8%), Unibet (~5.8%), Neds (~5.9%) and PointsBet (~5.6%) fell in between. Lower margin means more of each dollar stays with the bettor over time — though margin varies by sport and market, so treat these as sampled averages, not a guarantee on every price.

Worked example: a $20 multi across three legs

Multis (accumulators) multiply the odds of each leg together. Here's a three-leg multi on a weekend card:

• Leg 1: AFL — team at 1.80
• Leg 2: NRL — team at 2.10
• Leg 3: Premier League — team at 1.65

Combined odds = 1.80 × 2.10 × 1.65 = 6.237.

Stake $20. Total return if all three win = $20 × 6.237 = $124.74. Profit = $104.74.

Now the probability side. Each leg's implied chance:

• 1 ÷ 1.80 = 55.6%
• 1 ÷ 2.10 = 47.6%
• 1 ÷ 1.65 = 60.6%

Multiply them: 0.556 × 0.476 × 0.606 ≈ 16.0% implied chance of the whole multi landing. That's why multis pay big but hit rarely — every extra leg stacks the margin and shrinks your real probability of collecting. One losing leg and the whole ticket is dead.

Fixed odds vs tote (parimutuel) — a racing distinction

In horse racing you'll often see two prices side by side: fixed odds and the tote (parimutuel) dividend.

• Fixed odds lock in the price the moment you place the bet. If you take $4.00, you get paid at $4.00 regardless of what happens to the market afterwards.
• Tote pays a dividend calculated after the race, based on how the total pool was split among winning tickets. You don't know the exact payout when you bet — it can drift up or down.

Most bettors take fixed odds for certainty. The tote can occasionally beat the fixed price on a roughie, but you carry the risk of the dividend contracting if money floods in late. TAB, with its long-standing tote operation, is the operator most associated with pool betting in Australia, while the corporate books lead on fixed-odds racing markets. You can compare live prices on our horse racing odds page.

Why the same market is priced differently across bookmakers

No two bookmakers price a market identically. They set their own odds, apply their own margin, and shade prices based on where their customers are betting. That's why line-shopping matters — taking the best available price on the exact same outcome directly increases your return over time.

Our sampling captures how often each operator posted the top price. Across sampled markets, Unibet (best price on ~56% of samples) and Ladbrokes (~55%) topped the best-price share most frequently. Neds landed the best price around 36% of the time, TAB ~27%, bet365 ~23%, PointsBet ~24%, PlayUp ~14% and betr ~13%.

Read that alongside margin, not instead of it. A bookmaker can top the best-price table on a chunk of markets while still carrying a higher average margin overall — sample size and market mix both shape the numbers (Ladbrokes and Unibet were each sampled on 240-plus markets; bet365 on 30). The practical takeaway: keep two or three accounts open and check the price on your specific selection before you bet. Our comparisons and live betting odds pages make that quicker.

How live odds move during a match

In-play (live) betting prices shift constantly as the game unfolds — a goal in an A-League match, a wicket in a Big Bash innings, a break of serve on the WTA Tour. The bookmaker recalculates implied probabilities in real time and adjusts the decimal odds to match.

Cash Out builds on the same maths: the operator offers to buy back your bet at its current live value, which can be more or less than your potential full return depending on how the odds have moved. bet365, Sportsbet, Ladbrokes, Unibet, PointsBet, TAB and Neds all list Cash Out among their features. It's a way to lock in a profit or limit a loss before the result — but you pay for that flexibility in the margin baked into the live price.

Reading odds before you choose an operator

Odds quality is one input, not the whole decision. Match it to how you bet:

• Chase the sharpest average margin from our sample: Sportsbet (~4.9%) and PointsBet (~5.6%) sampled lowest. Good if price is your priority.
• Line-shop across the widest best-price coverage: Unibet and Ladbrokes topped the sampled best-price share most often — worth an account each for comparison.
• Want the deepest markets and in-play depth: bet365 rates highest on market coverage (9.6), sports depth (9.5) and live capability (9.4), though it carried the highest sampled margin — you trade a little price for breadth.
• App-first bettors: bet365 (app 9.3) and Sportsbet (app 9.0) rate strongest for mobile betting.

Every operator listed here is a licensed Australian bookmaker regulated by state and territory racing and wagering authorities, with the Northern Territory Racing Commission overseeing several corporate books. The legal minimum age to bet is 18. Always confirm an operator's current licence status before depositing — see our legal betting sites Australia page for the safety checks.