Is a $50 bonus bet worth $50? What it is worth at different prices

A $50 bonus bet is usually worth less than $50. If it pays only the profit and keeps the stake, its fair value is $50 × (1 − 1 ÷ decimal price): $25 at even money, $33.33 at +200 and $40 at +400. The margin in the price takes a few per cent off those figures, and a longer price raises the value and the variance.

The bonus bet calculator works the expected value and the locked-in value for any bonus and price.

Stake not returned

This is the common form. A win pays the profit only, S × (d − 1), and the stake S is never yours. A loss pays nothing, and costs you nothing because the stake was not your money. If the price is fair, the win chance is 1 ÷ d, so the expected value is (1 ÷ d) × S × (d − 1) = S × (1 − 1 ÷ d).

• Even money (d = 2.00): 0.50 × 50 = $25.00
• +200 (d = 3.00): 0.667 × 50 = $33.33
• +400 (d = 5.00): 0.80 × 50 = $40.00
• +900 (d = 10.00): 0.90 × 50 = $45.00
• -200 (d = 1.50): 0.333 × 50 = $16.67

The longer the price, the closer to face value, because the lost stake that you do not get back matters less against a larger prize. The stake is the missing piece: the free bet article shows the same effect as a difference of exactly one stake.

Stake returned

A less common form pays S × d on a win, stake included. The expected value at a fair price is (1 ÷ d) × S × d = S, the full $50 at any price. Check the terms: the difference between the two forms is exactly the stake, $50 on every win.

Locking it in changes the shape

The unhedged values above depend on a long shot landing. A bettor who wants a fixed result places a cash bet on the other side to lock in a smaller fixed amount, for example 50% and 72% of the face value in the two cases below. That calculation is in the lock-in article.

What the margin does

The price carries a margin, so the true win chance is a little below 1 ÷ d. At +400 with a 4.5% margin on the market the expected value of the $50 bonus is closer to $38 than $40. The effect is proportionally larger at short prices, where the stake is not returned, and smaller at long ones. Use the fair-price figures as a ceiling.

Terms that cut the value

• Expiry. Many bonus bets lapse within days. An unused one is worth nothing.
• Minimum price. Some require a minimum, such as -200 or longer, which rules out the short prices that give a low value anyway.
• Market limits. Only some markets qualify, and some exclude parlays or live bets.
• Wagering requirements. Winnings from some bonuses must be bet again before they can be withdrawn, as explained in the rollover article.

Put in your offer. The bonus bet calculator takes the amount, the price and whether the stake is returned.