Sportsbooks give away millions in bonus bets every year. “Bet $100, get $100 in bonus bets!” sounds great, but a $100 bonus bet isn’t worth $100 in cash. Understanding the real value — and how to maximize it — is free money on the table.
How Bonus Bets Work
A bonus bet (sometimes called a free bet) lets you place a wager without risking your own money. If you win, you keep the profit but not the original stake. If you lose, you lose nothing.
Regular $100 bet at +200:
Win: $300 returned ($200 profit + $100 stake)
Lose: -$100
$100 bonus bet at +200:
Win: $200 returned (profit only, no stake returned)
Lose: $0
The key difference: bonus bets don’t return the stake. This makes them worth less than their face value.
The Real Value of a Bonus Bet
The conversion rate tells you what percentage of the bonus bet’s face value you can expect to extract as real cash. Higher decimal odds mean a higher conversion rate.
Basic Formula
Conversion Rate = (Decimal Odds - 1) / Decimal Odds × Win Probability
For a simple estimate at fair odds:
Conversion Rate ≈ (Decimal Odds - 1) / Decimal Odds
| Odds | Decimal | Conversion Rate |
|---|---|---|
| -200 | 1.50 | 33.3% |
| -110 | 1.909 | 47.6% |
| +100 | 2.00 | 50.0% |
| +200 | 3.00 | 66.7% |
| +300 | 4.00 | 75.0% |
| +500 | 6.00 | 83.3% |
| +700 | 8.00 | 87.5% |
Longer odds = higher conversion rate. A $100 bonus bet used on a +300 underdog is worth about $75 in expected cash value. The same bonus bet on a -200 favorite is only worth about $33.
Conversion Strategies
Strategy 1: Bet on Underdogs (Simple)
The easiest approach is to use your bonus bet on the biggest underdog you can find. At +500 odds, you’re converting at ~83%. The downside: high variance. You’ll lose most of these bets, but when you win, the payout is large.
Best for: Casual bettors who don’t want to do math. Just pick a +300 to +700 underdog and let it ride.
Strategy 2: Hedge with Another Book (Guaranteed)
Place the bonus bet on one side at one book, then bet the opposite side with real money at another book. This locks in a guaranteed profit.
Example:
Bonus bet: $100 on Side A at +300 (Book 1)
Hedge: $250 on Side B at -250 (Book 2)
If Side A wins: $300 profit (bonus) - $250 hedge = +$50 If Side B wins: $0 loss (bonus) + $100 hedge profit - some calculations = varies
The exact hedge amount depends on the odds. Use the calculator to dial it in.
Best for: Maximizing guaranteed value. Typical conversion: 60-80%.
Strategy 3: Arbitrage Across Books
Find a market where combined odds across two books create an arbitrage opportunity, then use the bonus bet on one side. This maximizes the guaranteed conversion.
Best for: Experienced bettors who already line-shop across multiple books.
Common Mistakes
Using Bonus Bets on Heavy Favorites
A $100 bonus bet on a -500 favorite is only worth ~$17. You’re throwing away 83% of the value. Always use bonus bets on underdogs or even-money bets.
Letting Bonus Bets Expire
Most bonus bets have an expiration (7-14 days). A sub-optimal bet is better than no bet. If your bonus is about to expire and you haven’t found a great spot, just take a +200 or +300 underdog.
Not Hedging When You Should
If you have a $500+ bonus bet, hedging to guarantee $300-400 in cash is almost always worth it. Don’t gamble with large bonus values when you can lock in guaranteed money.
Ignoring Terms and Conditions
Some bonus bets have restrictions: minimum odds, excluded markets, or wagering requirements. Read the terms before planning your strategy.
Key Takeaways
Bonus bets are worth less than face value because the stake isn’t returned on a win
Use them on underdogs (+300 or higher) to maximize conversion rate
Hedge with a second book to guarantee a specific cash value
Never waste bonus bets on heavy favorites — the conversion rate is terrible
