Double Lay Calculator

The Double Lay calculator is specifically designed for 3-outcome markets where a bookmaker offers a refund (usually as a bonus bet) if one of the outcomes occurs that you did not bet on. These promotions are common in sports like soccer.

When to use it

Use the Double Lay calculator whenever you have a promotion like:

• "Money back as bonus bet if it's a draw"
• "Get your stake back if the match ends 0-0"
• "Refund if your team loses by 1 goal"

These are commonly found on soccer, AFL, and NRL matches where there's a specific outcome that triggers a refund.

How the promotion works

These promotions create three possible outcomes:

1. Your back bet wins: You win your bet normally at the bookmaker.
2. The refund condition triggers: Your back bet loses, but you receive a bonus bet refund (typically 80-100% of your stake).
3. Neither occurs: Your back bet loses and no refund is given.

To maximize value, you need to lay two outcomes:

• Lay your back bet at the exchange (to hedge the normal win)
• Lay the refund trigger at the exchange (to hedge getting the bonus bet)

Understanding the inputs

Back bet details

• Back Stake: The amount you're betting at the bookmaker.
• Back Odds: The odds for your back bet at the bookmaker.
• Back Commission: Commission on back bets (usually 0% at bookmakers).

Lay details

• Lay Odds (Back Bet Selection): The odds at which you can lay your back bet at the exchange.
• Lay Odds (Refund Outcome): The odds at which you can lay the refund trigger at the exchange.
• Lay Commission: The exchange commission rate.

Refund details

• Bonus Rate: What percentage of your stake is refunded (usually 100%, but some promotions offer less).
• Retention Rate: What percentage of the bonus bet you expect to convert to cash. Typically 70-80% depending on how you convert it.

Overlay/underlay

Like the Exchange calculator, you can adjust the slider to control your risk distribution. At 50% (balanced), all three outcomes yield equal profit.

Understanding the outputs

The calculator breaks down the profit for all three outcomes:

If your back bet wins

Shows your profit from:

• Bookmaker payout (minus your stake)
• Loss from the lay on your back bet
• Win from the lay on the refund trigger

If the refund triggers

Shows your profit from:

• Loss of your original stake at bookmaker
• The bonus bet you receive
• Win from the lay on your back bet
• Loss from the lay on the refund trigger

If neither occurs (the third outcome wins)

Shows your profit from:

• Loss of your original stake at bookmaker
• Win from both lay bets

Practical example

Sportsbet offers "Money back if draw" on a Soccer match between Melbourne City and Sydney FC, up to a stake of $100. The refund is given as a bonus bet, and you expect to retain 75% of its value:

• You back Melbourne City at 2.20
• Melbourne City lay odds: 2.24
• Draw lay odds: 8.0
• Exchange commission: 5%
• Refund: 100% as bonus bet
• Expected retention: 75%

There's no reason not to stake $100. Enter these values in the calculator with the slider at 50% (balanced).

The calculator recommends:

• Lay Melbourne City: $100.46
• Lay Draw: $9.43

This creates three scenarios:

1. Melbourne City wins: $4.40 profit
2. Draw: $4.40 profit (lose $100, get $75 value from bonus bet, win $29.40 from lays)
3. Sydney FC wins: $4.40 profit

You've locked in $4.40 profit regardless of what happens. Without the promotion, this market would have been unprofitable to match bet. This represents an EV of 4.4%.

Common issues

One of my lay stakes seems very small. Is this right?

Yes. The refund trigger is usually a low-probability outcome (like a draw in Soccer at 12.0 odds), so you don't need much stake to hedge it. The calculator is working correctly.

The refund trigger odds are huge (50.0+). Can I skip that lay?

You could, but you'll have unbalanced returns. Add the lay stake to your refund triggers outcome, and subtract it from the others to see your new profit distribution (note this doesn't account for commission, but will give you a rough indication).

What if there are multiple refund triggers?

Some promotions have multiple refund conditions (e.g., "money back if draw OR if it rains"). This calculator handles single-trigger scenarios. For multiple triggers, you'd need to lay each one separately, which gets complex quickly. Focus on promotions with a single, clear refund condition.

Should I always balance at 50%?

Not necessarily. If you're confident in your back bet, you might underlay (below 50%) to increase profit if it wins. If you think the refund is likely, you might overlay. But balanced is the safest approach and the recommended starting point.