Quick answer
A multi bet (also called an accumulator or parlay) combines two or more selections, called legs, into one bet. The odds of each leg are multiplied together, so the potential return is much bigger than backing each one separately. The catch: every leg has to win. If one loses, the whole multi loses, and each extra leg makes that more likely.
What you'll learn
- What a multi bet is and how the odds multiply
- How your chance of winning drops with each leg
- Same game multis and combo multis explained
- What happens when a leg is void, scratched or dead-heats
- A free multi bet calculator
Multis are one of the most popular bets in Australia, especially on weekend footy, racing and the summer cricket. They’re appealing because a small stake can return a large amount. But the maths behind them is often misunderstood. This guide explains exactly how a multi is priced and settled, with worked examples, so you can see what you’re really getting.
What is a multi bet?
A multi is a single bet made up of several selections. You can mix sports and events: an AFL result, an NBA result and a horse to win can all go into the same multi. Each selection is a leg. To collect, every leg must be successful. If all legs win, your return is your stake multiplied by the combined odds.
| Leg | Selection | Odds |
|---|---|---|
| 1 | AFL: Team A to win | $1.80 |
| 2 | NBL: Team B to win | $2.00 |
| 3 | BBL: over 160.5 first innings runs | $1.50 |
| Combined odds (1.80 × 2.00 × 1.50) | $5.40 | |
A $10 multi on those three legs returns $54.00 if all three win, a $44.00 profit. If any one of them loses, you get nothing back. Backing the same three selections as separate $10 bets would cost $30 and return between $0 and $53.00, depending on how many win.
How the odds multiply, and why the chance drops
Multiplying the odds also multiplies the risk. Decimal odds show an implied chance of winning: 1 ÷ odds. For a multi, you multiply those chances together. The table below uses legs at $1.90 each, a typical price for an even contest:
| Number of legs | Combined odds | $10 returns | Implied chance all legs win |
|---|---|---|---|
| 1 | $1.90 | $19.00 | 52.6% |
| 2 | $3.61 | $36.10 | 27.7% |
| 3 | $6.86 | $68.59 | 14.6% |
| 4 | $13.03 | $130.32 | 7.7% |
| 5 | $24.76 | $247.61 | 4.0% |
| 6 | $47.05 | $470.46 | 2.1% |
| 8 | $169.84 | $1,698.39 | 0.6% |
The margin compounds too
Bookmakers build a margin into every price. If a true 50/50 contest is offered at $1.90 instead of $2.00, you’re getting 95% of the fair odds. In a multi, that shortfall multiplies: five legs at 95% each gives you about 77% of the fair combined odds (0.95 × 0.95 × 0.95 × 0.95 × 0.95). The more legs you add, the bigger the bookmaker’s edge on the whole bet.
Multi bet calculator
Enter the decimal odds for each leg and your stake. The calculator shows the combined odds, your potential return, and the implied chance of every leg winning. Tick “void” on a leg to see how the bet changes if that leg is scratched or cancelled.
Free calculator
Multi bet calculator
Same game multis explained
A same game multi (SGM) combines several selections from one match, such as a team to win, a player to score and the total points going over a line. They’re hugely popular for AFL, NRL and NBA.
The key difference is that the legs are linked. If a team wins comfortably, its star player is more likely to have scored, and the total is more likely to be high. Because of that, bookmakers don’t simply multiply the odds in a same game multi. They price the combination with their own model, and the odds offered are usually lower than if you multiplied the individual prices.
| Standard multi | Same game multi | |
|---|---|---|
| Legs come from | Different games or events | One game |
| How odds are set | Each leg’s odds multiplied together | Priced as a package by the bookmaker |
| Can you check the maths? | Yes, with a calculator | Not exactly, because the legs are correlated |
| Void or scratched leg | Usually removed (odds of 1.00), the rest continues | Varies: some providers reprice the remaining legs, others void the whole bet |
Combo multis: covering more than one outcome
A combo multi (sometimes called a “multis within a multi” or system bet) lets some legs lose while still paying out. Instead of one bet that needs everything to win, you place every possible smaller multi from your selections. For example, picking four teams and taking “all doubles” means placing every two-leg multi from those four. This costs more because it’s several bets, but you can collect even if one or two legs miss.
| Selections | Doubles (2 legs) | Trebles (3 legs) | 4-leg multis | Cost of all doubles at $5 each |
|---|---|---|---|---|
| 3 | 3 | 1 | 0 | $15 |
| 4 | 6 | 4 | 1 | $30 |
| 5 | 10 | 10 | 5 | $50 |
| 6 | 15 | 20 | 15 | $75 |
Worked example: all doubles from four picks
You pick four teams at $1.90 each and take all six doubles at $5 each, so $30 in total. Each winning double returns $5 × 3.61 = $18.05. If three of your four picks win, three of the doubles come in and you get back $54.15. If only two win, one double pays $18.05 and you lose $11.95 overall. A straight four-leg multi at $30 would have returned $390.96 if all four won, but nothing if any missed.
What happens if a leg is void, scratched or dead-heats?
| Situation | Standard multi (usual rule) |
|---|---|
| A leg is void (game abandoned, player doesn’t take part) | That leg is treated as odds of $1.00. The multi continues on the remaining legs at lower combined odds |
| A horse in a leg is scratched | Treated as void, the same as above. Scratching deductions may apply to other runners |
| A leg finishes in a dead heat | That leg’s odds are reduced, usually divided by the number of runners in the dead heat |
| All legs are void | The stake is refunded |
For the example multi above, if the NBL leg at $2.00 is void, the bet carries on as a two-leg multi at $1.80 × $1.50 = $2.70. A $10 stake would then return $27.00 instead of $54.00. Rules for same game multis and promotional offers differ more widely, so check your provider’s terms before you bet.
Multi bet strategy: what actually helps
| Approach | Why it helps |
|---|---|
| Use fewer legs | Each leg you remove raises your chance of winning more than it lowers the return |
| Avoid adding very short-priced “certainties” | A $1.10 leg adds little to the odds but still has roughly a 1 in 11 chance of losing the whole bet |
| Check every leg’s odds separately | A poor price on one leg drags down the value of the whole multi |
| Stake what you’d be happy to lose | Most multis lose. Treat the stake as the cost of the entertainment |
| Read the void and dead-heat rules | Settlement can change your return significantly |
No strategy changes the basic maths: the more legs, the lower the chance. If you bet on the summer cricket, our Big Bash rules and betting guide explains each market, and how betting odds work covers the odds behind every leg. Racing fans can compare multis with trifectas and quaddies and each way bets.
Set a weekly limit before you start. Our guide to setting deposit limits explains how, and BetStop lets you exclude yourself from every licensed betting provider if you need a break.
Sources
Frequently asked questions
What is a multi bet?
A multi bet combines two or more selections into one bet. The odds are multiplied together for a bigger potential return, but every selection must win for the bet to pay.
How do you work out multi bet odds?
Multiply the decimal odds of every leg. Three legs at $1.80, $2.00 and $1.50 give combined odds of $5.40, so a $10 bet returns $54.00 if all three win.
What is a same game multi?
A same game multi combines several selections from one match, such as a team to win and a player to score. Because the legs are linked, the bookmaker prices them together, usually below the multiplied odds.
What happens if one leg of a multi is void?
In a standard multi, a void leg is usually treated as odds of $1.00 and removed, and the bet continues on the remaining legs. Same game multi rules vary, so check your provider’s terms.
Are combo multis worth it?
Combo multis let you collect even if some legs lose, but they cost more because each combination is a separate bet. They reduce the swings rather than improving the odds.
How many legs should a multi have?
There’s no right number, but each leg lowers your chance of winning. Five legs at $1.90 each have only about a 4% implied chance of all winning.
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