A bonus bet calculator shows how much real money a bonus bet is worth. A $50 bonus bet at 4.50, laid at 4.70 on an exchange with 5% commission, locks in about $35.75 whatever happens. That’s 71.5% of the face value, as cash, from a bet you didn’t pay for.
The free calculator above works it out for any bonus bet. It’s set in dollars for Australia, where free bets are called bonus bets, and you can switch currency at the top.
Bonus bet calculator: why you don’t get the full $50
Bonus bets are usually stake not returned. If your $50 bonus bet wins at 4.50, you get $175 profit, not $225. The $50 never comes back. That’s why converting one to cash always comes in under the face value, and why the odds you choose matter:
- Odds around 2.0: you keep roughly 45% to 50%.
- Odds of 4.0 to 6.0: usually 70% to 78%.
- Odds of 10.0 and up: 80% or more, but the exchange liability gets large.
The calculator shows the expected retention at 3.0, 6.0 and 10.0 so you can see the trade-off before picking a market.
How the lay works
You back the selection with the bonus bet at the bookmaker and lay the same selection on an exchange. If it wins, the bonus bet pays and the lay loses. If it loses, the lay wins. The lay stake is set so both outcomes come out the same:
Lay stake = bonus bet × (back odds − 1) ÷ (lay odds − commission)
$50 × 3.5 ÷ 4.65 = $37.63. Your liability on the exchange is $139.25, so you need that much in your exchange account. The tighter the gap between back and lay odds, the more you keep.
Bonus bets that return the stake
A few offers return the stake when the bonus bet wins. Pick “SR (stake comes back)” and the value jumps close to 100%. For the same maths in pounds, use the free bet calculator; for laying a normal cash bet, the lay calculator.
Bonus bets are marketing. Use them, but don’t deposit more to chase the next one. Gambling Help Online is free and confidential, any time of day.