Overview

The Bonus Calculator tells you the real cash value of a sportsbook or casino promo after wagering requirements, game contribution rates, and expected house edge are factored in. A headline like "Bet $5, Get $200 in Bonus Bets" sounds great, but bonus bets only return profit (not stake), and rollover requirements quietly shave off most of the advertised value. This tool converts marketing language into expected dollars.

The Formula

Formula: Expected Value = (Bonus Amount × Conversion Rate) − (Rollover × House Edge)

For bonus bets specifically, the conversion rate at fair odds (+100) is roughly 0.7 — you only keep winnings, not the stake, so a $100 bonus bet placed on a coin flip returns about $70 in expected cash.

When To Use It

Use it before claiming any deposit match, bonus-bet offer, casino reload, or first-bet insurance offer. It is especially important when comparing two offers that look similar on the surface — a $1,000 deposit match with 10x rollover is often worse than a $200 bonus bet with no playthrough.

Worked Example

Example 1: DraftKings offers "Bet $5, Get $200 in Bonus Bets." You place the bonus bets at average odds of +150 (decimal 2.5). Conversion rate at +150 is about 0.74. Expected cash value = $200 × 0.74 = $148. Subtract a small vig drag and you net roughly $140 in true value.

Example 2: BetMGM offers a $1,000 deposit match with 10x rollover at −110 odds (4.76% hold). Required action = $10,000. Expected loss to vig = $10,000 × 0.0476 = $476. Net EV = $1,000 − $476 = $524. Despite the bigger headline, both offers land in the same neighborhood — and the bonus-bet offer requires far less risk.

Common Mistakes

• Treating bonus bets like cash — they are worth ~70% of face value, not 100%.
• Ignoring game contribution on casino bonuses (blackjack often counts 10%, slots 100%).
• Forgetting max bet rules during playthrough, which can void the bonus entirely.
• Not subtracting your own vig drag on the qualifying wager.