Boxing 4 horses in a trifecta covers 24 combinations, so a full 100% ticket costs $24 at a $1 unit. If that is more than you want to spend, a flexi bet lets you pick your own outlay and collect the matching percentage of the dividend. For example, $12 across the 24 combinations is a 50% flexi.
Where the 24 combinations come from
Four horses can fill the first three places in 4 x 3 x 2 = 24 different orders. A box buys every one of them, so the cost is the number of combinations multiplied by your unit. At $1 that is $24. Only one of those 24 lines can win on the day, which is the price of not having to nominate the order. If you want the mechanics first, read how a boxed trifecta works.
100% versus a flexi percentage
Your flexi percentage is your outlay divided by the number of combinations. The table shows what four outlays hold, and what each collects if the trifecta pays $400 for a $1 unit. The $24 ticket collects $400, while the $10 ticket collects $166.67. You are not covering fewer outcomes, only taking a smaller share of the same ones.
| Outlay on 24 combinations | Flexi percentage | Collect on a $400 dividend |
|---|---|---|
| $24 | 100% | $400 |
| $15 | 62.5% | $250 |
| $12 | 50% | $200 |
| $10 | 41.67% | $166.67 |
Source: Calculated at a $1 unit on a hypothetical $400 dividend. Flexi percentage is outlay divided by combinations, per Racing and Sports flexi betting guide, as at November 2026.
Minimum bets and flexi rules to check
Minimums are set by the operator, so confirm yours before you build the ticket. The NSW Totalizator Rules list a racing unit of 50 cents, which would put a 100% four-horse box at $12 where the operator allows it. Racing and Sports describes a standard trifecta as a $1 minimum outlay. For flexi bets the NSW rules set the floor at the greater of 1 cent per combination or $5, unless TAB sets another amount, and Sportsbet states $1. The flexi percentage is shown before you confirm.
Frequently Asked Questions
Is boxing 4 horses much cheaper than boxing 5?
Yes. A 4-horse box is 24 combinations and a 5-horse box is 60, so at $1 you pay $24 against $60.
Does a flexi bet lower my chance of winning?
No. You still cover all 24 combinations, so you collect in the same situations. Only the size of the payout changes.
What does a 50% flexi pay?
It pays half of the official dividend for the winning combination. On a $400 dividend per $1 unit, that is $200.
Horse racing betting involves financial risk. Bet only what you can afford to lose. For support, visit Gambling Help Online or call 1800 858 858.