A sportsbook hands you a 100 dollar bonus bet and it feels like 100 dollars. It is not. Depending on how you use it, that same bonus bet is worth anywhere from about 20 dollars to roughly 75 dollars in real money, and most people unknowingly pick the version worth 20.

The reason is a single detail buried in the terms: when a bonus bet wins, you keep the profit but not the stake. That one rule changes the entire calculation, and it points to a strategy that is the opposite of what most bettors instinctively do.

This guide shows the arithmetic, the conversion rate at every price, and how to lock in a guaranteed cash return rather than hoping.

Why a Bonus Bet Is Not Worth Its Face Value

Place 100 dollars of your own money at plus 100 and win, and you get 200 dollars back: your 100 dollar stake plus 100 dollars of profit.

Place a 100 dollar bonus bet at plus 100 and win, and you get 100 dollars. The profit only. The bonus stake itself vanishes, because it was never your money to begin with.

So a bonus bet at even odds converts at roughly 50 percent. Half of the face value is gone before you start, purely because of how the stake is treated.

This is the entire mechanic, and nearly every mistake people make with bonus bets traces back to not understanding it.

The Conversion Rate at Every Price

Here is the useful consequence. Because you only ever collect the profit portion, the conversion rate depends directly on the odds you use the bonus bet at.

The formula, assuming a fair price, is simply the profit multiple divided by the total decimal odds:

Conversion rate = (decimal odds − 1) ÷ decimal odds

Run that across common prices and the pattern is stark.

Odds	Conversion rate	Value of a $100 bonus bet
minus 400	20.0%	$20
minus 200	33.3%	$33
minus 110	47.6%	$48
plus 100	50.0%	$50
plus 200	66.7%	$67
plus 300	75.0%	$75
plus 500	83.3%	$83
plus 1000	90.9%	$91

Read that table again, because it inverts the instinct almost everyone has.

The common approach is to use a bonus bet on something safe, reasoning that a sure thing guarantees you collect. That is precisely backwards. On a heavy favourite at minus 400, you are throwing away 80 percent of the bonus, because almost all of the return in that bet is the stake being handed back, and you never get the stake back.

The longer the odds, the larger the share of the return that is profit, and profit is the only part you keep.

The Catch

If longer odds convert better, why not use every bonus bet at plus 1000?

Because the conversion rate is an expected value, not a guarantee. A 100 dollar bonus bet at plus 1000 is worth about 91 dollars in expectation, but you only collect anything roughly nine percent of the time. Nine times out of ten you end up with nothing at all.

That is fine if you receive bonus bets regularly and can let the maths play out across dozens of them. It is uncomfortable if this is a one off promotion and you would rather have real money than a lottery ticket.

Which leads to the technique most people are actually searching for.

How to Lock In a Guaranteed Conversion

You can convert a bonus bet into cash with certainty by hedging it. Place the bonus bet on one side at long odds, then back the opposite side with real money at a different sportsbook, sized so that both outcomes return the same amount.

The hedge stake is:

Hedge = (bonus odds − 1) × bonus amount ÷ hedge odds

Here is a worked example.

You hold a 100 dollar bonus bet and place it on a team at plus 300, which is decimal 4.00. At another sportsbook, the opposing side is available at minus 350, which is decimal 1.2857.

Hedge = (4.00 − 1) × 100 ÷ 1.2857 = 300 ÷ 1.2857 = 233.33 dollars of your own money

Now check both outcomes.

If the plus 300 side wins: the bonus bet pays 300 dollars of profit, and you lose the 233.33 dollar hedge. Net result: 66.67 dollars.

If the minus 350 side wins: the hedge returns 66.67 dollars of profit, and the bonus bet loses, which costs you nothing real. Net result: 66.67 dollars.

Either way you walk away with 66.67 dollars in withdrawable cash from a 100 dollar bonus bet. A 66.7 percent conversion, guaranteed, with no outcome risk at all.

There is an elegant result hiding in that arithmetic. If both sides were priced with no margin at all, hedging would convert at exactly the same rate as simply holding the bonus bet and hoping. The difference is that hedging removes the variance entirely. What you actually give up is the vig on the hedge side, which is why the 66.7 percent here sits slightly below the 75 percent that a fair plus 300 price would imply.

Our bonus bet conversion calculator runs all of this for you, including the hedge sizing.

Reading the Terms Before You Plan Anything

Promotions carry conditions, and several of them will break the strategy above if you miss them.

Minimum odds requirements are the most common. Many books require the bonus bet to be used at minus 200 or longer, and some set the floor higher. That caps your conversion rate, because it caps how long the odds can be.

Expiry windows are often short, sometimes seven days. An unused bonus bet is worth exactly nothing.

No partial use. A bonus bet is almost always all or nothing. You cannot split a 100 dollar credit into four 25 dollar bets unless the terms explicitly allow it.

Market restrictions. Some promotions exclude certain sports, bet types or live markets.

Void and postponement rules. If your event is postponed and the bet voids, some books return the bonus bet and some do not. This matters a great deal if you have already placed a real money hedge.

That last point deserves emphasis. If the bonus side voids but your hedge stands, you are left holding an unhedged cash bet you never intended to make. Check the void policy before you commit to the hedge.

Common Mistakes

Using it on a heavy favourite. The single most expensive error. A 100 dollar bonus at minus 400 keeps 20 dollars. The same bonus at plus 300 keeps 75. The difference is pure arithmetic.

Letting it expire. Obvious, and still extremely common.

Hedging without checking the void rules. Covered above, and genuinely costly when it happens.

Hedging on the same sportsbook. Most books will not let you, and attempting it can flag your account.

Treating the face value as cash. A 500 dollar bonus bet offer is not a 500 dollar offer. At realistic odds it is worth perhaps 300 to 375 dollars, and that is the number you should use when comparing promotions between books.

Doing nothing but promotions. Worth knowing: sportsbooks watch for accounts that only appear to claim offers and then go dormant. Our guide to why sportsbooks limit winning bettors covers which behaviours draw attention and how to extend the life of an account.

Fitting This Into a Wider Approach

Bonus bet conversion is a one off gain rather than a repeatable edge. You claim the offer, you extract the value, and then it is over until the next promotion arrives. It is genuinely worth doing, and it is not a strategy on its own.

The repeatable version of the same skill is finding prices that are better than an outcome's true probability, which is what our explainer on +EV betting covers. The hedging mechanic above is also closely related to arbitrage betting, where you back both sides across different books to lock a guaranteed return.

Both of those depend on having accounts at several sportsbooks and on taking the best available price every time, which is the habit covered in our guide to line shopping. The same account spread that makes hedging possible is what makes everything else work too.

The Bottom Line

A bonus bet is worth less than its face value because you keep the profit and never the stake. How much less depends entirely on the odds you use it at, and the relationship runs opposite to intuition: longer odds convert better, because a larger share of the return is profit.

Used on a heavy favourite, a 100 dollar bonus bet is worth about 20 dollars. Used at plus 300 and hedged at another book, it converts to roughly 67 dollars of guaranteed, withdrawable cash.

Check the minimum odds requirement, check the void policy, then run the numbers through our bonus bet conversion calculator before you place anything.

Please play responsibly. Sports betting carries real financial risk, and no tool or strategy guarantees a profit. Promotional terms vary by operator and jurisdiction, so always read the specific conditions attached to any offer. If gambling is affecting your life, free and confidential support is available through the National Council on Problem Gambling. Must be of legal age in your jurisdiction.

How to Convert a Bonus Bet to Cash