MLB parlay fair price checker: is your price fair?
Your book quoted you an MLB parlay price. This checker works out what the ticket is really worth: enter each leg's price for your side and the other side of the same market — a run line, a total, a moneyline, or a player prop with both sides listed — and it removes the book's cut from every leg, multiplies the fair chances together, and puts the fair payout next to the one you were offered. Neutral numbers, no lecture — what you do with them is your call.
MLB note: run lines, totals and moneylines are two-sided markets, so they check cleanly here. Player props — the MLB machine's legs (hits, total bases, hits + runs + RBIs, pitcher strikeouts and the rest) — check only when your book lists both the over and the under at the same line: some prop lines are listed one way only, and a one-sided listing has no other side to read a fair price from, so this checker cannot price it; treat any fair chance for such a leg as an estimate, not a market price. Home-run legs check only when your book lists both the yes and the no side — a yes-only listing cannot be checked this way. Same-game parlays are repriced by books for correlation — a batter's hits, total bases and hits + runs + RBIs can all come from the same at-bats, and a pitcher's strikeouts and outs recorded move together — so this multiplication does not describe them either. The MLB machine on this site is live with daily pools; no current MLB lines are quoted in the examples below, and the examples are arithmetic only.
Your legs
American odds (for example -110 or +200). Use prices from one book for the whole ticket — a parlay is placed at a single book, so its fair price is read from that book's own market.
The headline
This ticket's real odds, from the market's fair price
| Your book | Fair price | |
|---|---|---|
| Parlay odds | ||
| Chance it implies | ||
| Payout on your stake |
The book's cut is the gap between the two payouts, as a share of the fair payout. It is information about the price, not a prediction about the ticket. Lines move — re-check with current prices before you bet. Same-game parlays are repriced by books for correlation, so this multiplication does not describe them. Legs with no two-sided market (some alt lines, one-sided props and yes-only home-run listings) cannot be checked this way; their fair chance is an estimate, not a market price.
Two MLB examples, worked in full
Example 1 — three run lines at -110
Three MLB run-line legs, each priced -110 on your side and -110 on the other side. Each leg's fair chance is exactly 50%. Fair chance for the ticket: 0.5 × 0.5 × 0.5 = 12.5% — 1 in 8 — a fair price of +700. If your book quotes +596, a $10 stake pays $69.60 at the book against $80.00 at the fair price: a $10.40 gap, 13.0% of the fair payout. Try it: the checker above is pre-loaded with exactly these legs.
Example 2 — a moneyline, a total, and a run line
A moneyline leg at -150 / +130 (fair chance 58.0%), a total leg at -110 / -110 (fair chance 50.0%), and a run-line leg at -120 / +100 (fair chance 52.2%). The moneyline's two sides imply 60.0% and 43.5%; scaled to 100%, your side's fair chance is 58.0%. Ticket fair chance: 58.0% × 50.0% × 52.2% = 15.1%, a fair price of +561. Enter -150 / +130, -110 / -110, and -120 / +100 above with a book's quoted price to see its payout beside the fair payout on your stake. These are arithmetic examples only — EXAMPLE, NOT A PICK — using round prices to show the method, not lines from any current game.
How it works, in 20 seconds
- Each price hides a chance. -150 implies 60%; +200 implies 33.3%.
- Both sides add to more than 100% — the extra is the book's cut. Scaling the two sides so they add to exactly 100% leaves the market's fair price for your side.
- Fair chances multiply. Three true coin flips: 0.5 × 0.5 × 0.5 = 12.5%, or 1 in 8 — a fair payout of +700. A book paying +596 on that ticket keeps about 13% of the fair payout.
- Compare. The checker puts your book's price and the fair price side by side, on your stake.
Want the machine to do the shopping?
Moonshot Parlays builds a ticket from real sportsbook lines — all checked against the market's fair price — and shows its real odds and what each book pays, at one picked book so the ticket can actually be placed there. Free, no sign-up.
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