- Pick Strategy: Matched (lock in profit) or EV (chase value).
- Enter Bonus Bet amount and odds. Bonus bets return only winnings, not the stake.
- Matched mode: Add hedge legs and pick a Target Outcome. Read Guaranteed Profit and Return %.
- EV mode: Enter Fair Odds and Bankroll. Read EV $, EV %, Kelly Stake, and Fractional Kelly.
Bonus Bet Calculator
A bonus bet calculator that converts a free bet into withdrawable cash. Enter the bonus amount, odds, and hedge line to see the optimal stake and conversion rate.
How to Use This Calculator
What is a bonus bet calculator?
A bonus bet calculator converts a sportsbook's bonus bet (also called a free bet) into withdrawable cash. It supports two strategies. The matched strategy hedges the bonus bet on a second sportsbook to lock in a predetermined return regardless of outcome. The EV strategy applies the bonus bet to a positive expected value market and skips the hedge, trading certainty for higher long-run value.
A bonus bet is the most common sportsbook promotion. Two defining characteristics: on a winning bet, the stake is not returned (only the winnings), and on a losing bet, no cash is lost. Since the bonus does not cost the bettor anything, the matched strategy leaves a positive cash position regardless of which side wins.
Formula (matched strategy)
\[
\begin{aligned}
\text{Bonus Winnings} &= \text{Bonus Amount} \times (\text{Decimal Odds} - 1) \\[6pt]
\text{Hedge Stake} &= \dfrac{\strut \text{Bonus Winnings}}{\strut \text{Hedge Decimal Odds}} \\[6pt]
\text{Conversion Rate} &= \dfrac{\strut \text{Net Profit}}{\strut \text{Bonus Amount}}
\end{aligned}
\]
Worked example (matched)
A bettor has a $100 bonus bet and applies it to a +200 line (decimal 3.00). To hedge, the opposing line is available at +180 (decimal 2.80).
\[
\begin{aligned}
\text{Bonus Winnings} &= 100 \times (3.00 - 1) = \$200 \\[6pt]
\text{Hedge Stake} &= \dfrac{\strut 200}{\strut 2.80} = \$71.43 \\[6pt]
\text{Net (bonus wins)} &= \$200 - \$71.43 = \$128.57 \\[6pt]
\text{Net (hedge wins)} &= 71.43 \times (2.80 - 1) = \$128.57 \\[6pt]
\text{Conversion Rate} &= \dfrac{\strut 128.57}{\strut 100} = 71.4\%
\end{aligned}
\]
Either way, $128.57 conversion on a $100 bonus, a 71.4% rate.
Why bonus bet conversion matters for matched bettors
Bonus bets are the single largest source of matched betting profit. Every major US sportsbook offers them, sign-up offers depend on them, and ongoing promotions deliver them regularly. The conversion rate depends on the odds chosen and the price of the opposing side. Typical conversion rates range from 65% to 80%.
The DarkHorse Odds Bonus Bet Finder scans real-time prices across sportsbooks and surfaces the best available conversions for any bonus bet. Use this calculator to verify a specific opportunity or to understand the math.
For the full strategy, read How to Convert a Bonus Bet. The Second Chance Bet Calculator handles the related promotion where the refund is delivered as a bonus bet.
Common mistakes
- Using bonus bets on favorites. Because bonus bet stakes are not returned on a win, low-odds bets produce poor conversion rates. Avoid odds shorter than about +150.
- Forgetting about expiration. Most bonus bets expire 7 to 14 days after being credited. Plan conversions promptly.
- Confusing bonus bets with site credit. Site credit acts more like cash and converts at a higher rate. See our Site Credit guide for the difference.
- Hedging at a different sportsbook with very low limits. The hedge stake on a large bonus bet can be substantial. Confirm the hedge book accepts the size before placing the bonus bet.
Frequently Asked Questions
What is a bonus bet calculator?
A bonus bet calculator sizes the cash hedge required to convert a sportsbook's bonus bet (free bet) into withdrawable money. It supports both matched betting (lock in profit) and EV betting (chase value) strategies.
How do you convert a bonus bet to cash?
Place the bonus bet on one outcome at plus money (+) odds. On a second sportsbook, place an offsetting cash bet on the opposing outcome, sized so the cash result is equal regardless of which side wins. The bonus bet itself costs nothing, so the cash result is positive in both scenarios.
What is the difference between matched and EV strategies for a bonus bet?
Matched locks in a predetermined return by hedging on a second sportsbook. EV applies the bonus bet to a positive expected value market without hedging, accepting variance in exchange for higher expected value. Matched is the default for most matched bettors; EV is appropriate when the bonus is small relative to bankroll and the underlying bet is meaningfully +EV.
What is the difference between a bonus bet and a free bet?
There is no functional difference. Different sportsbooks use different names: bonus bet, free bet, bet credit. The mechanics are identical: stake is not returned, only the winnings. The conversion math is the same.
What is the difference between a bonus bet and site credit?
Bonus bets return only the winnings on a successful bet. Site credit at many sportsbooks does the same, but at some books, site credit behaves like cash and returns both the stake and the winnings on a win. Cash-style site credit converts at a much higher rate than a bonus bet.
What odds should I use to convert a bonus bet?
Generally +200 to +400 produces strong conversion rates. Going higher increases conversion at the cost of variance. Going lower (closer to even money) reduces conversion.
Why isn't bonus bet conversion 100%?
Because the hedge bet costs cash. The conversion rate is the percentage of the bonus value retained as cash after paying for the hedge.
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