Oz Lotto Odds Explained

How Oz Lotto works

Oz Lotto is an Australian lottery drawn every Tuesday. Each game on a ticket contains 7 different numbers chosen from 1 to 47. In the draw, 7 winning numbers are selected, and then 3 supplementary numbers are drawn from the balls that are left. To win the top prize you need all 7 main numbers. The supplementary numbers come into play only at some of the lower prize levels, where a certain number of main numbers is combined with one or more supplementaries. The official prize table defines exactly which combinations form each prize division.

Where the jackpot odds come from

The jackpot figure is simply a count of every possible ticket. If you list every way to choose 7 different numbers from 47, where the order does not matter, you end up with 62,891,499 combinations. Only one of them matches the 7 winning numbers in a given draw, so a single game has a 1 in 62,891,499 chance of winning the top prize.

The lower prize levels work the same way. Mathematicians count how many of those 62,891,499 combinations contain, for example, exactly 5 of the winning numbers, and divide. Because many more tickets match 4 numbers than 7, the odds of the smaller prizes are far shorter.

Oz Lotto odds explained

Here are the odds for a single game, based on the current 7 from 47 format:

• All 7 main numbers: 1 in 62,891,499
• 6 main numbers plus 1 supplementary: 1 in 2,994,833
• 6 main numbers and no supplementary: 1 in 242,824
• 5 main numbers plus at least 1 supplementary: 1 in 26,270
• 5 main numbers and no supplementary: 1 in 4,497
• Exactly 4 main numbers: 1 in 182
• 3 main numbers plus at least 1 supplementary: 1 in 70.90

If you ignore the supplementary numbers altogether, the chance of matching exactly 6 main numbers is 1 in 224,612, exactly 5 is 1 in 3,840 and exactly 3 is 1 in 19.66. Whether a particular match actually wins anything depends on the official prize table.

What 1 in 62.9 million really means

Large numbers are hard to picture, so it helps to translate them into time. Imagine you entered one game of Oz Lotto every Tuesday without fail. With 52 draws a year, you would need to play for around 1.2 million years before you could expect, on average, one jackpot win. Even then, there would be no guarantee: the odds stay the same in every draw, no matter how long you have been playing.

Another way to look at it: if you could write every possible Oz Lotto combination on a separate slip of paper and put them all in a giant drum, you would be searching for one particular slip among almost 63 million. Your ticket is one slip, and the draw picks one slip.

The 2022 change: from 45 to 47 numbers

Until May 2022, Oz Lotto players chose 7 numbers from 1 to 45. Adding just two more numbers to the pool has a much bigger effect than it seems. With 45 numbers there were 45,379,620 possible combinations; with 47 there are 62,891,499. That is about 1.386 times as many, which makes the jackpot roughly 39 per cent harder to win with a single game.

This shows how sensitive lottery odds are to the size of the pool. Each extra ball does not just add a few new tickets; it creates millions of new combinations, because every new number can be paired with every existing set of six others. The lower prize levels changed too, although less dramatically than the top prize.

Why no strategy changes the odds

Every Oz Lotto draw is independent. The machine has no memory, so numbers that came up last week are not more likely to appear again, and numbers that have been absent for months are not overdue. Believing otherwise is known as the gambler's fallacy. Charts of hot and cold numbers describe the past; they cannot predict the next draw.

The same applies to systems based on patterns, sums, odd and even splits or birthdays. Any specific set of 7 numbers, including 1, 2, 3, 4, 5, 6, 7, has exactly the same 1 in 62,891,499 chance as any other.

The only thing your choice can influence is how many people you might share a prize with. Popular patterns and dates are chosen by many players, so if they win, the prize for that level may be divided between more people. Random picks, such as those from our random number generator, tend to avoid those crowded choices. That can reduce the chance of sharing a prize, but it does not make you any more likely to win.

Play responsibly

In Australia you must be 18 or over to buy a lottery ticket. Treat Oz Lotto as entertainment, not as a way to earn income or solve financial problems. Decide on a budget you can comfortably afford to lose before you play, and stick to it. Never chase losses or spend money meant for bills and essentials. For current rules, eligibility, ticketing and results, always check the official Australian lottery operator's publications. If gambling stops being fun, support services are available in every state and territory.

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