Sports betting calculator: bonus value, parlay and odds

How the bonus value is worked out

The sports betting bonus calculator uses plain expected value. It does not predict whether your bet wins. It says what an offer is worth on average if you could place the same bet many times. The three offer types follow different rules, so each has its own formula.

Bonus bets

A bonus bet is a free stake that is not returned when it wins. You keep the profit only. If the decimal odds are d and the market hold is h, the chance of winning is about (1 − h) / d, and the expected value of a bonus of size B is B × (1 − h) × (d − 1) / d. At 5% hold, a $100 bonus bet placed at +100 is worth about $47.50 on average, and at +200 about $63.33. Longer odds convert more of the bonus into expected cash, but they also make it more likely that the bet pays nothing.

Second-chance bets

A second-chance offer refunds a losing first bet as bonus bets. You risk your own money, so the calculator takes the value of the refund, which you only get when the bet loses, and subtracts the expected cost of the qualifying bet, which is the stake times the hold. With a $100 first bet at +200 and 5% hold, the chance of winning is about 31.7%, the expected refund is $43.28 and the net value is $38.28.

Deposit match with play-through

A match gives you bonus credit that becomes cash only after you wager a multiple of an amount, known as the play-through or rollover. Each dollar you wager costs you the hold on average. The value is therefore the bonus minus the hold times the total amount you must wager. A $100 bonus with a one-time play-through on the bonus is worth about $95 at 5% hold. With a ten-time play-through it is worth about $50, and a play-through applied to deposit plus bonus costs more again.

These figures describe averages. A single bet either wins or loses, and playing through a bonus can end with less than you started with. Real offers add conditions the calculator cannot see, such as minimum odds per bet, an expiry date, excluded markets and limits on withdrawals, so read the operator's terms before you rely on a number. The value shown is an estimate for comparing offers, and no offer is a reason to bet money you cannot afford to lose.

How a parlay is priced from the odds

The decimal odds of each leg are multiplied together, and the result is your payout multiplier. Three legs at -110, -110 and +150 combine to decimal odds of 9.11, which is +811 in American odds, so a $10 stake pays $91.12 in total, a profit of $81.12. Because every leg must win, the chance of cashing a parlay is the product of the chances of its legs, and it falls quickly as you add more. The sportsbook's margin is also applied to every leg, so it compounds. Parlays pay well when they hit, and the same compounding is why they cost more on average than single bets.

To see how a play-through works, try the wagering requirement explorer. For converting prices and removing the margin from a market, use the betting odds calculator. If a term here is new to you, the learn section explains American odds, implied probability and the hold from the start.

Comparing two offers: a worked example

Suppose you are choosing between three offers. Offer A gives $200 in bonus bets once you place a first bet. Offer B matches a $100 deposit with $100 of bonus credit, and the credit must be played through ten times before it turns into cash. Offer C refunds a lost first bet of up to $100 as bonus bets. Every one of them can be advertised with the same kind of big headline. At a hold of 5% and bets placed at +200, the calculator gives very different values.

The ranking is A, then B, then C, and the gap is wide. Offer A converts about 63% of its headline into expected value at these odds, and it is worth more than three times Offer C. Offer B looks generous at $100, yet the play-through takes half of it back in expected margin. These figures depend on your own choices. Change the odds, the hold or the play-through and the order can change, which is why the calculator takes them as inputs and does not fix them.

What the hold does to the answer

The hold is the margin built into the prices you bet at. A lower hold means a bonus keeps more of its value, and a higher hold takes more. Standard markets on major sports are usually priced at the lower end, and exotic markets, props and same game parlays are often priced higher. If you are not sure, run the calculator at three values and see whether your conclusion survives.

A bonus bet is far less sensitive to the hold than a play-through, because it is wagered once. A play-through multiplies the hold by every dollar you must wager, so a higher hold or a longer requirement erodes it quickly.

The terms that change the value

Offers are described in a handful of recurring terms. The calculator covers the ones that can be turned into numbers. The rest limit what you can do with the offer, and they are worth reading before you opt in.

Expiry is the one most readers forget. A bonus that expires in seven days is worth less to someone who bets once a week than to someone who bets daily, and the calculator cannot know your habits. Minimum odds also matter: if the offer requires short prices, the share of the bonus you can convert drops.

Using a sports betting calculator before you open an account

1. Find the offer's terms on the operator's own page and note the type, the amount, the play-through and the minimum odds.
2. Enter them in the bonus value calculator, using the odds you would really bet at.
3. Run it at two or three levels of hold to see how stable the answer is.
4. Compare the dollar value of each offer, not the headline amounts.
5. Read the full terms for limits the calculator cannot see, such as expiry and excluded markets.
6. Set a deposit limit in the app before you fund the account.

A sports betting calculator shows what an offer is worth on average, and it cannot tell you whether to bet. Nothing here is a reason to bet. An offer is worth taking only if you would have bet on the app anyway, and only with money you can afford to lose. If gambling stops being fun, call 1-800-GAMBLER.

Which calculator answers which question

The tools on this site look at a bet from different angles, so it helps to know which sports betting calculator fits the question in front of you. If you have an offer and want to know what it is worth after the play-through, start with the bonus value calculator on this page. If you only want to see how a wagering requirement grows as you bet, the wagering requirement explorer shows the total stakes, step by step.

If you are holding a price and want to know what chance it implies, or what the market would look like without the sportsbook's margin, use the odds calculator. If you are looking at a ticket with several legs, the full parlay calculator takes up to 12 of them and can add your own chances to show an average result. All of them use the same arithmetic, so the numbers agree when you move from one to another.

If you can see the same market at more than one app and want to know which price is best for your side and which market costs least, use the odds comparison calculator. If you want to set a limit before you bet and see what a stake size means for it, use the betting budget planner.

Frequently asked questions