The ball that only matters after you have already matched something
A lotto draw does not end when the last main number leaves the machine. In many formats, the operator then draws one more ball from the same drum or a separate one. That ball is the bonus number, and it has a strange property: it never pays anything by itself. You cannot win a prize for matching only the bonus number. What it does is upgrade certain near-misses into a higher prize tier, and it only does that for players who have already matched most of the main numbers.
This matters because a player who checks a ticket and sees the bonus number among their picks can easily misread what they have won. The bonus number sits in a separate column on the results page for a reason. Treating it as a sixth main number inflates the apparent value of a ticket that, under the printed prize table, sits one division lower.
How one draw sequence unfolds
Imagine a 6-from-45 lotto with a bonus number. The machine selects six main numbers, and those six alone define the first division. The draw then continues and produces one additional number from the remaining balls. That is the bonus number. It is not a seventh main number, and it cannot combine with five main numbers to form a six-number match. The first division is closed the moment the sixth main ball is drawn.
The bonus number exists for the second division. In a typical structure, a player who matches five main numbers plus the bonus number wins the second prize, while a player who matches five main numbers without it wins the third prize. The bonus number therefore decides which of two adjacent prize tiers a five-number match falls into. It does not change how many main numbers the player matched.
Some formats draw the bonus number from the same drum immediately after the main set. Others use a second, smaller drum holding a different range, such as 1 to 10 or 1 to 20. The operator's own game rules page states which method applies, and the results display usually labels the bonus ball separately so players do not count it as a main number.
What the bonus number can and cannot do
The cleanest way to think about the bonus number is that it is a tiebreaker for a specific level of partial match. It never creates a win from nothing, and it never upgrades a low-level match into a high one. A player with four main numbers and the bonus number has matched four main numbers, full stop. The bonus number does not make that five.
| Situation | What the bonus number does |
|---|---|
| Matched all main numbers | Irrelevant; first division is decided by the main set alone |
| Matched all but one main number, plus the bonus | Places the ticket in the higher of the two near-miss divisions |
| Matched all but one main number, without the bonus | Places the ticket in the lower near-miss division |
| Matched fewer main numbers, with or without the bonus | No effect; the ticket is judged on main numbers only |
| Matched only the bonus number | No prize under any standard lotto format |
Because the bonus number only separates two adjacent divisions, its financial effect is the difference between those two prize amounts, not the full value of the higher division. On a fixed-prize game the two amounts are printed in the prize table. On a pari-mutuel game, where prize pools are split among all winners in a division, the number of other players who also matched the bonus number determines how thinly the second-division pool is divided.
Why the prize table is the only reliable guide
Lotto formats differ sharply across operators and jurisdictions. Some games have no bonus number at all and instead use a supplementary game, a second draw, or a multiplier ball. Others have two supplementary numbers. The phrase "bonus number" is not a universal standard; it is a label that each game defines in its own rules.
That means no general article can tell a player which division a five-plus-bonus match falls into for their specific ticket. The document that can is the prize table published on the operator's results page or on the back of the physical playslip. The table lists every division, the number of main numbers required, whether the bonus number participates, and the prize or prize-pool share attached. Reading it before checking a ticket prevents the most common misreading, which is counting the bonus ball as a main number and expecting a division the ticket did not enter.
Where the bonus number fits in the odds
Adding a bonus number does not make a lotto game easier to win. The first division still requires every main number, and the probability of that is set by the main pool size and the number of balls drawn. The bonus number adds a second condition to the second division: a player must not only match five main numbers but also match one further ball from the remaining pool. That is a harder condition than matching five main numbers alone, which is why the second division usually pays more than the third.
The odds of matching the bonus number after already matching five main numbers depend on how many balls remain in the drum at that point. In a 6-from-45 game, after six main balls are drawn, 39 balls remain, so a player with five main numbers has a 1-in-39 chance that their remaining number is the bonus ball. That arithmetic is specific to a 6-from-45 format and is offered only as an example of how the calculation works; the operator's published odds table gives the exact figure for any given game.
One consequence follows from this structure: the bonus number creates a large gap between the second and third divisions in expected value, because the second division requires an extra successful prediction on top of the near-miss. A player who habitually buys tickets should understand that the bonus number is not a consolation prize. It is a second hurdle placed in front of the second division, and it exists to make that division rarer and therefore larger when it is won.
Procedural mistakes around the bonus number
The first mistake is checking results in the wrong order. A player who scans the main numbers, sees five matches, and then notices the bonus number among their picks may celebrate a second-division win before confirming that the bonus number on the results page matches one of their remaining numbers. The bonus number must be compared against the ticket just like any other drawn number; it is not automatically awarded.
The second mistake is assuming the bonus number applies to every prize division. In most formats it applies only to the second division, or to the second and one other. A player who matches four main numbers and the bonus number has not moved into the five-number divisions. The prize table states which divisions use the bonus number, and that list is usually short.
The third mistake is treating the bonus number as a wildcard that can substitute for a missed main number. It cannot. If the six main numbers are 4, 11, 23, 31, 40, 44 and the bonus is 17, a ticket holding 4, 11, 23, 31, 40, 17 has matched five main numbers plus the bonus, not six main numbers. The sixth main number, 44, is missing, and no bonus ball fills that gap.
FAQ
Can I win anything with just the bonus number?
No. The bonus number only has meaning when combined with a specific level of main-number match, usually five main numbers. A ticket that matches the bonus number and nothing else is not a winning ticket under any standard lotto prize table.
Does the bonus number change the odds of winning the jackpot?
No. The jackpot or first division is decided entirely by the main number set. The bonus number adds a condition to a lower division, making that division harder to hit, but it does not affect the probability of matching every main number.
How do I know if my game uses a bonus number or a different kind of supplementary ball?
Look at the prize table on the operator's results page or the game rules printed on the playslip. The table will list each division, how many main numbers are required, and whether a bonus or supplementary number participates. If no division mentions a bonus number, the game does not use one.
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This article is general information about how these mechanics work. It is not legal advice and not a recommendation to gamble or to use any particular operator. Availability and legality differ by jurisdiction — check the rules that apply where you are.