Sportsbooks hand out bonus bets (also called free bets or site credit) constantly. Most bettors use them on a favorite and get a small, disappointing return. With a little math you can turn a bonus bet into 60–75% of its face value in cash, often guaranteed.
How bonus bets work
The key detail: a bonus bet's stake is not returned when it wins. You only get the profit.
- $100 cash bet at +100 wins → you get $200 back
- $100 bonus bet at +100 wins → you get $100 back
So a bonus bet is worth only the profit portion of the odds. That changes the optimal strategy completely.
Why long odds are better
Expected value of a $100 bonus bet at fair odds:
| Odds | Win chance (fair) | Expected value |
|---|---|---|
| −200 | 66.7% | $33 |
| +100 | 50% | $50 |
| +300 | 25% | $75 |
| +600 | 14.3% | $86 |
The longer the odds, the closer you get to face value, because a smaller share of the payout is the stake you do not get back. In practice books add more margin to longshots, so the sweet spot is usually around +250 to +500.
The hedge: locked-in conversion
Bet the bonus bet on one side at Book A, and hedge the other side with cash at Book B.
Example: $100 bonus bet.
- Book A: Team X +400 (bonus bet) → wins $400
- Book B: Team Y −450 (decimal 1.222)
Hedge stake = bonus profit ÷ hedge decimal = 400 ÷ 1.222 = $327.27
- If X wins: +$400 − $327.27 = +$72.73
- If Y wins: $327.27 × 0.222 = +$72.73
You lock in about $73, a 73% conversion, whatever happens.
The general formula
For a bonus bet of size B at decimal odds D₁, hedged at decimal D₂:
Conversion % = (D₁ − 1) × (1 − 1/D₂). Use the bonus bet converter to run the numbers instantly, or let the OddsHype promos page find the best conversion pairs across your books.
What conversion rate is good?
- 70%+: excellent
- 60–70%: good, typical
- Below 55%: look harder for a better pair
Better conversion comes from low-hold pairs: the best price on each side across books. (Low-hold betting.)
Should you always hedge?
Not necessarily. Hedging trades expected value for certainty. If your bankroll is comfortable, betting the bonus at good long odds without hedging has a slightly higher expected value (you do not pay the margin on the hedge). If certainty matters more (small bankroll, one-off promo), hedge.
Matched betting
Hedging promos across two books is the US version of matched betting. (Matched betting in the US.)
Rules to check
- Minimum odds requirements
- Expiry dates (often 7 days)
- Eligible markets
- Whether bonus bets can be split into smaller bets
Frequently asked questions
What is the best way to use a bonus bet?
Bet it at longer odds (roughly +250 to +500) and, if you want certainty, hedge the other side with cash at another book.
Why don't bonus bets return the stake?
That is how sportsbooks structure them: only winnings are paid, which is why bonus bets are worth less than cash.
What is a good bonus bet conversion rate?
Around 65–75% of face value when hedged with good odds on both sides.