Kalshi Parlay & Combo Calculator
Joint probability, combined payout, and break-even rate for any multi-leg Kalshi or Polymarket parlay.
A Kalshi parlay (also called a combo or multi-leg) ties two or more prediction market contracts together so every leg must resolve YES for the parlay to pay. The joint probabilityis the product of each leg's individual probability — and this free calculator runs that math, converts it into a fair price, and shows you whether the combined market is offering positive expected value before you take the trade.
Stacking legs from the same match? This calculator assumes the legs are independent (it multiplies them). For same-game combos that's wrong — the legs move together, and the joint probability is higher than the product. Try the free Combo Edge Builder instead — it prices the correlation-aware joint probability from a scoreline model and flags where assembling correlated Kalshi legs is structurally underpriced. →
Quick Answer
the Combo Builder computes the joint probability and combined payout for a multi-leg Kalshi parlay, with break-even and EV comparison. For independent legs the joint probability is the product of each leg — two legs at 70% and 65% give 45.5% — almost always lower than it feels.
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Chain multiple Kalshi markets together like a parlay
What is this?
Think of Kalshi Combos like parlays in sports betting — you link multiple YES/NO predictions together and the payout multiplies. But unlike sportsbook parlays, there's no built-in house juice destroying the odds.
The Combo Builder calculates the exact probability and payout of any multi-leg Kalshi position instantly, so you know if you're getting a fair deal or leaving money on the table.
Real-World Example
→ Your 3-Leg Combo
You want to combine: (1) "Brazil makes the World Cup Final" at 35¢, (2) "Mbappé scores in the tournament" at 72¢, and (3) "Over 2.5 goals in the WC Final" at 58¢.
Combo Builder multiplies it out: 0.35 × 0.72 × 0.58 = 14.6% true probability. A fair price would be 14.6¢. If Kalshi is offering it at 10¢ — that's a mispriced combo in your favor.
✅Action: Build 3-leg combos. Compare the offered price to the calculated fair value. Only play if the offered price is lower.
Bottom line: If Kalshi's combo price is LOWER than your calculated fair value, you have an edge. This tool shows you which combos are mispriced.
Full guide →Combo Legs (2/4)
Combined Prob
42.0%
Cost
42.0¢
Payout Mult.
2.38x
Break-Even
42.0%
How Kalshi Combos Work
A Kalshi combo (also called a multi-leg or parlay) lets you tie multiple prediction market contracts together so that all legs must resolve in your favor for the combo to pay out. The math is straightforward: each leg's implied probability gets multiplied together to produce the combined probability. A two-leg combo of 70¢ and 65¢ contracts has a combined probability of 0.70 × 0.65 = 45.5%, which means you'd pay roughly 45.5¢ and receive $1.00 if both legs hit.
The appeal of combos is the payout multiplier. Because you're accepting a lower win probability, your effective payout increases dramatically. A four-leg combo of fairly-priced 60¢ contracts would cost about 13¢ and return $1.00 — a 7.7x payout. This compresses your required capital while amplifying upside. The key question sharp bettors always ask is whether the combo is positive expected value (EV) — do the combined fair probabilities justify the combo price?
Unlike sportsbook parlays, Kalshi combos do not charge additional vig per leg. Each leg's pricing already embeds the platform's edge. This makes Kalshi combos structurally more transparent than traditional parlay products and is one of the reasons experienced DFS and sports bettors are migrating toward prediction market platforms for high-upside plays.
Compare Kalshi parlays to sportsbook parlays
Deep Dive
Frequently Asked Questions
How do you calculate joint probability for a Kalshi parlay?
Joint probability for a Kalshi parlay is the product of each leg's individual probability, assuming the legs are independent. Two legs at 70% and 65% give a joint probability of 0.70 × 0.65 = 45.5%. The Combo Builder above does this math for you across any number of legs, converts the joint probability to a fair price, and compares that fair price to what the combined market is actually charging — so you can spot positive-EV Kalshi parlays at a glance. If your legs are correlated, the true joint probability is higher or lower than the simple product, which is why we recommend sticking to independent legs.
What is a Kalshi parlay (combo) and how does joint probability work?
A Kalshi parlay (or combo, or multi-leg) ties multiple prediction market contracts together so every leg must resolve YES for the parlay to pay out. The joint probability — the chance every leg hits — is the product of each leg's individual probability when the legs are independent. Parlays offer higher payouts in exchange for lower joint probability — similar to a sportsbook parlay but with Kalshi's transparent, vig-free pricing per leg.
How do I calculate the expected value of a Kalshi combo?
Enter each leg's probability into the Combo Builder. The tool calculates the combined probability, the fair combo price, and compares it to the actual cost. If the fair price is higher than the market cost, the combo has positive expected value. Unlock the EV rating with Picks Pro for automatic EV calculation on all combos.
When should I use combos vs single-leg prediction market trades on Kalshi?
Use combos when you have high conviction on multiple correlated events and want amplified upside with lower capital. Use single-leg trades when you have a specific edge on one market that you want to size correctly with Kelly Criterion. Combos reduce your win rate but increase payout multiplier — only use them when the legs are genuinely independent.
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