Free Bet Conversion

Quick Definition

Free bet conversion is the technique of extracting guaranteed cash value from sportsbook free bets. By backing a selection with your free bet and simultaneously laying the same selection on a betting exchange, you cancel out the game outcome and keep a percentage of the free bet value as guaranteed profit. Typical conversion rates are 70-85% of the free bet value.

Why Free Bets Need Converting

A free bet is not the same as cash. If you receive a £30 free bet and bet it on a 50/50 outcome at +100 odds, you have a 50% chance of winning £30 and a 50% chance of winning nothing. Expected value: £15. But you cannot guarantee the £15.

Free bet conversion eliminates this uncertainty. By laying the same outcome on an exchange, you guarantee a profit regardless of the game result. The guaranteed profit is typically 70-85% of the free bet value, depending on the odds you choose.

The Conversion Formula

Guaranteed profit = Free bet value × Conversion rate

Conversion rate = (Back odds - 1) / Back odds × (1 - Exchange commission)

At 5.00 back odds with 2% exchange commission:

• Conversion rate = (5.00 - 1) / 5.00 × (1 - 0.02) = 0.80 × 0.98 = 78.4%
• £30 free bet → £23.52 guaranteed profit

At 8.00 back odds with 2% exchange commission:

• Conversion rate = (8.00 - 1) / 8.00 × 0.98 = 0.875 × 0.98 = 85.75%
• £30 free bet → £25.73 guaranteed profit

Higher odds = higher conversion rate. This is why matched bettors target odds of 5.00-10.00 for free bet conversion.

Step-by-Step Conversion Process

Step 1: Identify a free bet offer. Example: Bet365 gives you £30 in free bets.

Step 2: Find a suitable market. You need a selection with:

• Back odds of 5.00-10.00 at the sportsbook
• Matching lay odds available on the exchange
• Small back/lay spread (ideally less than 0.10)

Step 3: Calculate the lay stake.

Lay stake = (Free bet value × Back odds) / Lay odds

For a £30 free bet at 6.00 back / 6.10 lay:

• Lay stake = (£30 × 6.00) / 6.10 = £29.51

Step 4: Place the back bet with the free bet at the sportsbook.

Step 5: Place the lay bet on the exchange.

Step 6: Calculate your guaranteed profit.

If selection wins:

• Sportsbook pays: £30 × (6.00 - 1) = £150 (free bet does not return stake)
• Exchange costs: £29.51 × (6.10 - 1) = £150.51
• Net: -£0.51

If selection loses:

• Sportsbook costs: £0 (free bet, no stake returned)
• Exchange pays: £29.51
• Net: +£29.51

Average guaranteed profit: approximately £14.50 (48% conversion rate at these odds)

Wait, this seems low. Let me recalculate with better odds selection.

At 8.00 back / 8.10 lay with 2% commission:

• Lay stake = (£30 × 8.00) / 8.10 = £29.63

If selection wins:

• Sportsbook pays: £30 × 7.00 = £210
• Exchange costs: £29.63 × 7.10 = £210.37
• Net: -£0.37

If selection loses:

• Sportsbook costs: £0
• Exchange pays: £29.63 × (1 - 0.02) = £29.04
• Net: +£29.04

Guaranteed profit: approximately £14.34 per outcome… but wait.

The key insight: with a free bet, the stake is NOT returned if you win. So:

If selection wins: You get £210 from sportsbook (profit only), pay £210.37 to exchange. Net: -£0.37 If selection loses: You get £0 from sportsbook, get £29.04 from exchange. Net: +£29.04

These are not equal, but both are positive (or near-zero). The average is approximately £14.34, which is a 47.8% conversion rate.

The correct calculation for maximum conversion:

To maximize conversion, you want the “if wins” outcome to also be positive. This requires:

Lay stake = Free bet value × Back odds / Lay odds

At 8.00 back / 8.10 lay:

• Lay stake = £30 × 8.00 / 8.10 = £29.63

If wins: £210 - £29.63 × 7.10 = £210 - £210.37 = -£0.37 (tiny loss) If loses: £29.63 × 0.98 = £29.04 (profit)

The “if wins” outcome is slightly negative due to the back/lay spread. The “if loses” outcome is the main profit. Average: approximately £14.34.

For a true guaranteed profit on BOTH outcomes, you need the back odds to be higher than the lay odds, which is impossible in normal markets. The best you can do is minimize the “if wins” loss while maximizing the “if loses” profit.

Maximizing Conversion Rate

Choose higher odds. At 3.00 odds, conversion rate is approximately 60%. At 8.00 odds, it is approximately 80%. The difference on a £100 free bet is £20.

Minimize the back/lay spread. A 0.10 spread at 8.00 costs approximately 1.2% conversion. A 0.20 spread costs 2.4%. Use liquid markets where spreads are tight.

Use low-commission exchanges. Smarkets charges 2% vs Betfair’s 5%. On a £100 free bet, this saves approximately £3.

Time your bets. Liquidity is highest during peak hours (evenings for football, weekends for most sports). Better liquidity means tighter spreads.

Free Bet Types and Their Value

SNR (Stake Not Returned): The most common type. Your stake is not returned if you win. Conversion rate: 70-85%.

SR (Stake Returned): Your stake is returned if you win. Conversion rate: 85-95%. More valuable than SNR free bets.

Profit boost: A percentage increase on your winnings. Conversion rate depends on the boost percentage and odds.

Deposit bonus: A cash bonus added to your account. Treated as cash, not a free bet. Conversion rate: 90-95% (small qualifying loss).

US Free Bet Conversion

US sportsbooks offer different promotion types:

• Bet and Get: Bet $X, receive $Y in free bets. Standard SNR conversion applies.
• Profit Boost: Percentage increase on winnings. Convert by backing at high odds.
• Deposit Match: Bonus cash with playthrough requirements. Requires multiple bets to clear.

US bettors use ProfitDuel and OddsJam’s promo converter to identify and execute these conversions.

Risk-Free Introduction

Start with a small free bet offer (£10-20) to practice the mechanics. Use a matched betting calculator to determine the exact lay stake. Place both bets and verify the outcome matches your calculation.

After 3-5 successful conversions, you will understand the process intuitively and can scale to larger offers.

Related Terms

• Matched Betting - The broader strategy that uses free bet conversion
• Lay Betting - The exchange bet used in conversion
• Betting Exchange - The platform for lay bets
• Vig - The margin that free bets help overcome