Bonus Bet Calculator

This bonus bet calculator turns a sportsbook’s stake-not-returned bonus into two hard numbers: the profit you keep if it wins at American odds like +200, and the guaranteed cash you can lock in by laying it off.

What Is a Bonus Bet?

A bonus bet is the term US sportsbooks now use for what used to be called a free bet, and it comes with one catch that changes everything: it is stake-not-returned. Place a normal cash wager and win, and you get your stake back plus profit. Place a bonus bet and win, and you keep only the profit - the bonus amount never lands back in your account. That single rule flips the usual betting logic on its head.

Because the stake disappears either way, a bonus bet is worth the most when the odds are long. On a short favorite, the profit is thin and the forfeited stake represents most of the bet’s real value. On a longshot, the profit dwarfs the stake, so forfeiting it costs comparatively little. That is why bonus-bet strategy points toward longer odds rather than safe, short prices.

This calculator gives you the two numbers that matter when a book credits you a bonus bet: the raw profit if it wins outright, and the guaranteed cash value you can extract right now by laying it off on a betting exchange. Together, those figures tell you whether a bonus bet is worth holding for the win or locking in immediately.

How a Bonus Bet Is Calculated

For a stake-not-returned bonus bet, the profit if it wins is the bonus amount multiplied by (decimal odds minus 1). Decimal odds strip out the fact that your stake is never returned - subtracting 1 isolates the profit portion of the payout, the only part you actually collect. Take American odds of +200: convert to decimal by dividing 200 by 100 and adding 1, giving 3.00. Subtract 1 and you are left with 2.00, the profit multiplier, which you then apply to the bonus amount to get the dollar profit if the bonus bet wins.

The longer the odds, the higher that profit climbs relative to the size of the bonus, because the (decimal odds - 1) term grows directly with the odds while the bonus amount itself stays fixed no matter what price you choose.

The second figure, the guaranteed cash value, comes from laying the bonus bet off on an exchange instead. Laying converts the bet from “win everything or nothing” into a certain payout, since you are effectively betting against your own bonus bet at exchange odds, net of commission. Retention - the share kept as guaranteed cash - rises as the odds lengthen, typically landing between 60% and 80% of the bonus amount. Short, even-money-type prices retain far less of the bonus’s face value than long prices do.

What the Calculator Shows You

The calculator produces two output figures once you enter a bonus-bet amount and the American odds you plan to use. The first is the profit if it wins: the dollar amount you would keep if the bonus bet settles as a winner, remembering the bonus stake itself is never returned. The second is the guaranteed cash value: what that same bonus bet is worth today if you lay it off on an exchange instead of waiting on the result, converting an all-or-nothing bonus into a fixed, certain amount. Reading both side by side lets you judge whether a bonus bet is worth more to you as a longshot swing for profit or as an immediate cash-out, and lets you compare value across different odds before committing.

Worked Example

Take a $50 bonus bet, stake not returned, placed at +200. Converting +200 to decimal odds gives 3.00. Using the formula - bonus amount x (decimal odds - 1) - the profit if the bonus bet wins is $50 x (3.00 - 1), which comes to $100.00. That is the number that lands in your account if the bet settles as a winner: $100.00 in profit, not $150.00, because the original $50 bonus stake is never returned to you.

Now consider laying that same $50 bonus bet off on an exchange charging 2% commission. At +200 odds, the lay retention works out to 67.1% of the bonus amount. Applying that retention rate to the $50 bonus bet gives a cash value of $33.56 - money you can lock in immediately, regardless of what happens in the game, without having to wait for the final score.

So the $50 bonus bet at +200 has two distinct values depending on what you decide to do with it: hold it and you are chasing a $100.00 profit if it wins, nothing at all if it loses. Lay it off and you are guaranteed $33.56 in real cash right now, no matter the outcome - roughly 67% of the $50 bonus, far more than the roughly 50% you would keep laying off the same bonus bet at even-money odds instead. That is the core lesson behind this calculator: the longer the odds attached to a bonus bet, the more of its face value converts into guaranteed cash, and the bigger the potential profit if you decide to let it ride instead of locking anything in.

Value of a $50 Bonus Bet by Odds (Stake Not Returned)

The table below shows how much a fixed $50 bonus bet is worth across four different American odds, stake not returned throughout. Look at how the profit if it wins and the lay retention percentage both climb together as the odds lengthen from +100 out to +500, while the cash value you could lock in in by laying off rises alongside them.

The Bonus-Bet Price in Each Odds Format

Sportsbooks and exchanges quote the same price in different formats, and it helps to see them lined up together for the odds this calculator deals with most: +100, +200, +300, and +500. The table below converts each of those American odds into its decimal equivalent, its fractional equivalent, and its implied probability, so you can recognize the same price no matter which format a book or exchange happens to display.

Why the Stake-Not-Returned Rule Changes Everything

The stake-not-returned rule is the whole reason bonus-bet strategy differs from betting your own cash. With a cash wager, both short and long odds return your stake if you win, so the length of the odds is neutral - you simply pick the bet you like best. A bonus bet removes that neutrality entirely. Because you forfeit the stake regardless of the odds, every dollar of value has to come from the profit portion of the payout alone. That is why retention climbs from about 50% at even-money odds up to over 80% at +500 - the profit share grows faster than the stake you are giving up.

The trade-off is variance. A bonus bet at +500 wins far less often than one at shorter odds, so to smooth that swing you either lay it off on an exchange for a guaranteed, fixed cash value, or hold it and accept fewer wins but a bigger one when it lands.

It also pays to read the fine print before counting on the raw math. Some bonus bets cap the maximum odds you may use, expire on a short clock, or exclude certain markets - any of which can cap the value this calculator would otherwise suggest.

When a Bonus Bet Makes Sense

A bonus bet makes the most sense when you treat it differently from your own cash from the outset. Because the stake is never returned, the strongest play is usually to attach it to longer odds rather than a short, safe favorite - the retention math above shows why a longshot price returns far more of the bonus’s face value than an even-money price does. If your goal is to squeeze the maximum guaranteed cash out of a bonus bet, pairing it with the longest odds your bankroll and risk tolerance allow, then laying it off on an exchange, is the most reliable route.

That said, laying off is not free - it requires an exchange account, ties up collateral while the lay bet is open, and hands a slice of the value to the exchange as commission. If you would rather chase the larger, uncertain profit instead of a smaller certain one, holding the bonus bet through to settlement is a reasonable alternative on a bonus bet small enough that the swing does not matter to your overall bankroll. Either way, treat the expiry date and any market or odds restrictions as part of the decision - a bonus bet that expires unused, or is restricted to odds shorter than you wanted, is worth less than the raw calculation implies.

Common Mistakes

Placing a bonus bet on a short favorite wastes most of its value, since the forfeited stake costs the most when the odds are short. Forgetting that the stake is not returned leads to overestimating a winning bonus bet’s payout - you keep the profit only, never the bonus itself. Ignoring maximum-odds or market limits in the bonus terms can quietly cap the value this calculator suggests. Letting a bonus bet expire before extracting its value, whether by holding it or laying it off, throws away money that was already yours.

Bonus Bet vs a Cash Bet of the Same Size

A cash bet returns your stake on a win and is odds-neutral, so any price is fair game. A bonus bet never returns its stake, so its value depends heavily on using longer odds, as the table below makes clear.