Parlay Calculator

A parlay combines multiple bets into one wager — all legs must win for the parlay to pay. The math is multiplicative: stake your bet on a product of probabilities and a product of payouts.

Example: 3 legs at 1.80, 2.10, and 1.95. Parlay decimal = 7.371. A $10 stake returns $73.71 ($63.71 profit). Implied probability = 13.6%.

Every leg of a parlay carries the bookmaker's margin (vig). Margins compound multiplicatively, just like odds:

• Single bet: ~4.5% margin on a balanced market (1.91/1.91 line).
• 3-leg parlay of -110 lines: 1 − (1/1.91)³ × parlay_odds = roughly 13% house edge.
• 5-leg parlay of -110 lines: compounds to 21% house edge.

Bookmakers love parlays because they look high-value to the bettor (big payouts) but extract triple the margin of single bets. The only way to beat them: build every leg from verified positive-EV picks — that's what our EV Builder mode is for.

Switch to EV Builder mode and add legs from our live +EV feed. For each leg we already know the no-vig fair probability (derived from market consensus across 94 bookmakers). The builder computes:

A parlay with EV > 0% is mispriced in your favor — rare, but it happens when you combine soft prices the book hasn't repriced yet. Variance remains brutal — bankroll sizing matters (see Kelly calculator).

Three real parlay scenarios that show why the math matters.

Example 1 — The textbook 3-leg parlay (−EV)

Three NBA spread bets, each priced at standard −1.91 (decimal). $100 stake. Implied probabilities 52.38% each. The book offers a 7.62× parlay payout.

Expected loss of $12.90 per $100 staked. Compare to a single −1.91 bet at fair prices: house edge ~4.55%. The parlay nearly triples the bookmaker's edge. That's the compounding-vig trap.

Example 2 — A real +EV parlay (rare but possible)

Two soft-line bets the book hasn't repriced yet:

• Leg A: NHL puckline at 2.30, our model says fair probability is 48% (fair odds 2.083).
• Leg B: MLB total under 8.5 at 1.95, fair probability 54% (fair odds 1.852).

Strong positive EV, but win rate is only ~26%. You will lose this parlay 3 out of 4 times. Bankroll sizing via fractional Kelly is essential — the math says bet around 0.5% of bankroll per parlay, not 5%.

Example 3 — Why same-game parlays (SGPs) are different

You build an SGP: Mahomes 250+ passing yards (1.80) + Chiefs win (1.65) + Travis Kelce anytime TD (2.10). If these were independent:

The book reprices because the legs are correlated — if Mahomes throws for 250+ yards, the Chiefs are more likely to win, and Kelce is more likely to score. Books model correlation and skim 20–40% extra margin on top. SGPs typically carry the highest house edge on the menu — use this calculator's Classic mode to see what an honest multiplicative parlay would have paid, and you'll never buy an SGP again.

• Standard parlay (accumulator / acca): multiple independent bets across different events. All must win. Payout = product of decimal odds.
• Same-game parlay (SGP): multiple bets within a single event. Repriced for correlation — always carries higher margin than standard parlay.
• Round robin: a parlay generator that creates every possible smaller parlay from a list of selections. Example: 5 picks → ten 2-leg parlays + ten 3-leg + five 4-leg + one 5-leg. Reduces variance, also reduces upside.
• Teaser: NFL/NBA-only. You shift point spreads in your favor (e.g. +6 → +12) in exchange for a lower payout per leg. Modern teasers are usually −EV; legacy "Wong teasers" on key numbers (3, 7, 10) used to be +EV but books now reprice them.
• Pleaser: opposite of a teaser — you shift spreads against yourself for a bigger payout. Almost universally −EV. Avoid.
• If-bet / reverse: sequential bets where leg 2 only fires if leg 1 wins. Lower variance than a parlay but also lower upside.
• Parlay insurance / boost: promo where the book refunds one losing leg. Sometimes flips a parlay to +EV — worth screening promos systematically.

• Leg: one bet inside a parlay. Each leg must win for the parlay to pay.
• Push leg: if a leg pushes (ties), most US books drop that leg and reprice the parlay. UK books often graded it as a loss historically — always check the rules.
• No-vig fair probability: the true probability of an outcome after stripping the bookmaker's margin. Sharp bettors think in fair probs, not raw implied probs.
• Implied probability of a parlay: 1 / (product of decimal odds). The price the book is charging you, not the true chance.
• Closing line value (CLV): on parlays, harder to measure but still useful. If every leg moved against you by closing, the parlay was likely sharp.
• Variance: standard deviation of outcomes. A 5-leg parlay with 50% legs has only 3.1% hit rate — even if EV is positive, you'll see long losing streaks.
• Kelly fraction: the optimal bet size as a percentage of bankroll. For parlays, always use a small fraction (5–25% of full Kelly) to survive variance.