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Parlay Calculator

Combine 2 to 12 legs in American or decimal odds. Get the exact payout, profit, combined decimal odds, and combined implied probability, recomputed live as you type.

Your parlay

Enter a price per leg. Pick American (e.g. -110, +150) or decimal (e.g. 1.91) per leg.
Total payout
$0.00
Profit$0.00
Combined decimal odds1.0000
Combined American odds+0
Implied probability0.0000
Legs counted0

How it works

A parlay pays only if every leg wins, so the odds multiply. The math is exact, not an estimate. Here is the whole thing. 

# 1. convert each leg to decimal odds
American positive A  ->  decimal = A / 100 + 1        # +150  -> 2.50
American negative A  ->  decimal = 100 / |A| + 1      # -200  -> 1.50
Decimal odds         ->  used as entered              # 1.91  -> 1.91

# 2. combine
combined_decimal   = product of all leg decimals
payout             = stake * combined_decimal
profit             = payout - stake
implied_probability = 1 / combined_decimal
  1. Convert every leg to decimal odds. Decimal odds are the multiplier on your stake if that single leg wins, stake included.
  2. Multiply the decimals together. The product is your combined decimal odds for the whole parlay.
  3. Multiply by your stake for the payout. Subtract the stake to get profit.
  4. Take 1 divided by the combined decimal odds for the parlay's implied probability, the break-even win rate the price is asking of you.

Building this into an app? This is the same devig and fair-odds math ParlayAPI's /v1/ev and /v1/devig endpoints run at scale across 45+ sources. Get it via the API, or start free at /pricing.