Convert American odds first
DraftKings' betting glossary provides one current US operator reference for American, decimal and parlay terminology. Decimal odds are useful for multiplication because they include the returned stake.
For negative American odds:
Decimal price = 1 + 100 / absolute American price
Illustrative -110 price = 1 + 100 / 110 = 1.9091
For positive American odds:
Decimal price = 1 + American price / 100
Illustrative +150 price = 1 + 150 / 100 = 2.50
Keep more precision than the interface displays. Rounding every leg early can create a visible difference on a longer ticket.
Worked standard parlay calculation
Suppose three illustrative selections are accepted at -110, +120 and -125. Their decimal equivalents are approximately 1.9091, 2.20 and 1.80.
Combined decimal price = 1.9091 * 2.20 * 1.80 = 7.5600
Gross return on a $20 stake = 20 * 7.56 = $151.20
Net profit = 151.20 - 20 = $131.20
For a positive combined decimal price above 2.00, an approximate American display is:
Positive American price = (7.56 - 1) * 100 = +656
The sportsbook's accepted display controls the contract. An independent calculation is a reconciliation check, not a substitute for the receipt.
Raw break-even probability
Under OpenStax's probability terminology, the reciprocal of decimal odds is a raw break-even probability before costs and model uncertainty:
Raw break-even probability = 1 / 7.56 = 0.1323, or 13.23%
This raw figure is not evidence that the joint event actually has that probability, particularly when each leg contains margin or the legs are related.
Price multiplication is not probability multiplication
For a standard ticket, multiplying accepted decimal prices calculates the contractual payout. Multiplying estimated probabilities is valid only under an independence assumption. OpenStax distinguishes independent from related events.
| Task | Correct input |
|---|---|
| Reproduce standard parlay return | Accepted full-precision leg prices |
| Estimate joint chance for independent legs | Independently estimated marginal probabilities |
| Estimate joint chance for related legs | Conditional probabilities or a direct joint model |
| Judge expected value | Joint probabilities and net payoffs for every settlement state |
Same-game prices
Do not multiply standalone prices to recreate a same-game parlay unless the product explicitly uses that method. Related selections are commonly accepted, rejected or repriced as one joint product. DraftKings' market rules provide one current example of separate same-game-parlay treatment.
Push and void calculation
Suppose the middle 2.20 leg in the worked standard ticket is removed under the accepted rules.
Revised decimal price = 1.9091 * 1.80 = 3.4364
Revised gross return on $20 = 20 * 3.4364 = $68.73
The actual operator may use retained internal precision or product-specific repricing, so the account result can differ by a cent from a calculation based on rounded display values.
Calculation record
| Field | Record |
|---|---|
| Original American price | The exact signed display for every leg |
| Decimal conversion | Full precision used for the check |
| Accepted combined price | The contractual ticket value |
| Stake | Cash amount debited |
| Potential gross return | Stake included |
| Settlement changes | Push, void, repricing and correction history |
| Final cash return | Amount credited after final settlement |
Expected value is a separate calculation using probabilities and net payoffs under OpenStax's framework.
Next step
Use Decimal Odds Explained for the next part of this topic.
Continue learning
- Next guide: DraftKings Soccer Parlays
- Related guide: FanDuel Soccer Parlays
Assumptions and limitations
Examples are illustrative and omit promotions, taxes, limits and state-specific restrictions. American-odds conversion and display rounding can vary at tie boundaries. Related-leg and void treatment follow the accepted sportsbook rules rather than one universal formula.
GambleAware
GamCare
Gambling Therapy
GAMSTOP