Bonus bet turnover calculator

Free tool to work out the optimal lay stake for converting an Australian bookmaker bonus bet (Stake Not Returned) into cash. Enter your bonus amount, the back odds available at the bookmaker, the lay odds available at the exchange, and the exchange commission. The calculator shows the exact lay stake to place, the guaranteed profit, and the effective conversion rate.

Not sure what any of this means? Scroll below the calculator.

What is a bonus bet, and why do you need to "turn it over"?

Australian bookmakers give out bonus bets as signup and retention promos. These are almost always Stake Not Returned (SNR), which means:

• If your bet wins, you get the profit only, not the stake back
• If your bet loses, you get nothing

That is why a $50 bonus bet is not the same as $50 cash. A $50 bonus at odds of 2.00 pays $50 if it wins (versus $100 for a cash bet at the same odds). To convert a bonus into cash with minimum risk, matched bettors "turn it over" by laying the same outcome at a betting exchange.

How the conversion works

Two bets, opposite sides of the same market:

1. Back the bonus bet at a bookmaker on the outcome. Higher back odds mean a higher potential conversion rate (because SNR bonuses give you more upside on longer odds).
2. Lay the same outcome at Betfair (or another exchange). The lay stake is calculated so that regardless of which side wins, you lock in the same guaranteed profit in cash.

The formula the calculator uses:

lay stake = bonus stake × (back odds − 1) ÷ (lay odds − commission)

Where commission is expressed as a decimal (5% = 0.05). Guaranteed profit = lay stake × (1 − commission).

Where the conversion rate comes from

• Higher back odds = higher conversion rate. A $50 bonus at back 5.00 / lay 5.10 converts around 78%. The same bonus at back 2.00 / lay 2.05 converts around 47%. Longer odds get more of the bonus value out.
• Smaller lay-to-back spread = higher conversion rate. If back and lay are 3.50 vs 3.55, you keep most of the bonus. If they are 3.50 vs 4.20, the exchange charges a fat spread and your conversion collapses.
• Lower commission = higher conversion rate. Betfair Australia's standard commission is 5%. Newer / promotional accounts sometimes have discounted rates.

Practical rule: target back odds around 3.00 to 5.00, tight lay spread (0.05 to 0.15 above back), 5% commission. That combination consistently converts 70 to 80% of the bonus.

When to use this

• Signup bonuses. Nearly every AU bookmaker offers a signup bonus in bonus-bet form (Sportsbet, TAB, Neds, Ladbrokes, Bet365, PointsBet, etc). Sign up, wager the qualifying deposit, receive the bonus, turn it over.
• Retention offers. Losing-bet refunds, bet-back promos, and other reactivation offers are often paid in bonus bets.
• Promo boost mishaps. If a boost drops a real cash bet into your account as a bonus (uncommon but happens), same maths applies.

When NOT to use this

• Cash bets. A regular cash bet is not SNR; the formula would over-pay the lay side. Use a matched-betting cash calculator for those.
• Multi bonus bets. Multi bonuses with more than one leg change the maths meaningfully because you need to hedge each leg. Not what this tool is designed for.
• Bonuses that require turnover before withdrawal. Some bookmaker bonuses require you to turn over the bonus amount several times before it converts to real cash. Read the terms carefully. This calculator assumes a straight-forward one-off SNR bet.

A worked example

Sportsbet signup: $50 bonus bet.

You look up the AFL Round 22 markets, find a game with:

• Back odds at Sportsbet on the underdog: 3.80
• Lay odds at Betfair on the same underdog: 3.90
• Betfair commission: 5%

Enter these into the calculator:

• Lay stake: $47.44
• Lay liability: $137.58
• Guaranteed profit: $45.07
• Conversion rate: 90.1%

Regardless of who wins, you walk away with about $45 in cash from the $50 bonus. That is a strong conversion, driven by longer back odds and a tight lay spread.

You then repeat the process at TAB, Neds, Ladbrokes and any other AU book with a signup offer. A punter with fresh accounts at 8 to 10 AU bookies can typically convert $500+ in signup bonuses in a weekend.

Frequently asked questions

Do I need a Betfair account?

Yes. Betfair Australia is the only major sports betting exchange operating under an Australian licence. Sign up, verify your account, and load enough funds to cover the lay liability shown by the calculator (the liability is significantly larger than the lay stake because you are on the hook if the lay side loses).

Is this legal?

Yes. Placing bets through licensed Australian bookmakers and Betfair is legal for individuals in Australia. Read our is +EV betting legal in Australia explainer for detail on the underlying legal framework.

Will bookmakers restrict my account for doing this?

Sometimes. Matched betting leaves a characteristic pattern in a bookmaker's data (mostly betting when a bonus is active, then not betting) that some bookies flag quickly. Others tolerate it for months. Signup offers are usually safe to turn over. Sustained bonus-only betting on a mature account is more likely to trigger restriction.

Can I do this with a bonus that requires wagering the bonus multiple times?

Not directly with this calculator, which assumes a single SNR bet turnover. Multi-turnover bonuses need a different approach (usually multiple smaller bets against lays, absorbing some variance across each). A dedicated matched-betting platform (OzProfit, Bonusbank, AussieBonusBets) handles those better.

What if the lay odds are lower than the back odds?

The calculator warns you if this happens. In practice it is unusual for the exchange to price a market below the bookmaker (usually the opposite). If it does, the maths still works but the resulting profit is often larger than the bonus value, which is suspicious. Double-check the market is what you think it is.

Where do I go after I have finished the signup bonuses?

Turnover bonuses are the on-ramp. Once you have exhausted the signup offers across all AU books, the next stage is finding +EV bets on live markets. That is what The Punt Edge does. See how +EV betting works for the underlying maths, or start the free trial.