Overview

A parlay combines two or more bets into a single ticket — every leg must win for the parlay to cash. The payout multiplies because the probabilities multiply, but so does the vig. The Parlay Calculator converts each leg to decimal odds, multiplies them together, and returns the total payout, profit, and combined American price.

The Formula

Formula: ParlayDecimal = DecOdds1 × DecOdds2 × ... × DecOddsN

The implied parlay probability equals the product of each leg’s implied probability — assuming legs are independent. Correlated legs (same-game parlays) require an adjusted model.

When To Use It

Use it any time you build a multi-leg ticket, want to compare a parlay payout to placing the legs individually, or need to assess whether a sportsbook is shorting you on the parlay price. Most books pay true odds on standard parlays but apply correlation penalties on SGPs.

Worked Example

Example 1: A 3-leg parlay with legs at −110 (1.909), +150 (2.5), and −200 (1.5). Combined decimal = 1.909 × 2.5 × 1.5 = 7.16. A $50 stake returns $358 (profit $308), or +616 in American odds. Combined implied probability = 1 / 7.16 = 14.0%.

Example 2: A 5-leg parlay of all −110 favorites. Each leg = 1.909 decimal, parlay = 1.909^5 = 25.4. $20 stake returns $508 (profit $488), or +2440. The fair price (no vig) for five 50% bets is +3100, so the book is taking roughly 22% hold on the ticket — much higher than the 4.8% per leg.

Common Mistakes

• Treating correlated legs as independent, which inflates expected payout.
• Comparing parlay payouts to a single book without shopping — parlay prices vary significantly.
• Stacking heavy favorites for a small price boost while accepting massive vig.
• Ignoring push rules: many books drop the parlay to fewer legs on a push, which actually helps you.