Alternate Line Calculator

Fair price at every line—

Give the main line and its two prices and this becomes a fair ladder up and down from it.

Main lineOver priceUnder price

Derived ladder — fair prices per line

LineOver probFair overFair under

0.5O 93.1%−1350+1350

1.5O 74.7%−295+295

2.5O 50.0%eveneven

3.5O 28.0%+257−257

4.5O 13.3%+650−650

5.5O 5.5%+1729−1729

A Poisson derivative of the market: λ is fitted so the model matches the devigged main line (50.0%over), then read up and down the ladder. Honest for count props; compare any book’s alternate price against these fair numbers.

Show the math

solve λ: 1 − CDF(⌊main⌋, λ) = p_fair(over)λ = 2.674

rung fair = P(over)/(P(over)+P(under)) — push excluded

Send this calculation

Your numbers travel in the link — whoever opens it sees this exact calculation.

KeyboardUp and down arrows step any price — 5 cents on an American number, a hundredth on a decimal. Enter moves to the next field. Slash jumps back to the first one from anywhere on the page.

What this will not claimA Poisson derivative of the market you typed. The ladder is honest for count props and it inherits every assumption the model makes about the shape of the distribution.

Related calculators

Poisson CalculatorExpected rate → over/under/exact probabilities and fair odds for any count line.Half-Point CalculatorWhat the market says a half point is worth — devigged win probability at both lines.No-Vig Fair Odds CalculatorStrip the book's margin from a two-sided market — three devig methods side by side.All 13 calculators →

How are alternate lines priced?

Alternate lines can be priced from the main market alone: strip the vig from the posted line, fit a Poisson rate to the fair probability, and the model then prices every other line up and down the ladder.

How it works & common questions

It is a market-implied derivative, honest for count props: compare any book's alternate quote against the derived fair price to see which rungs are shaded and which are soft.

How it works

Enter the main line and both prices. The posted over/under and the two sides' odds.
The model fits λ. Solved so the Poisson over-probability equals the devigged market number.
Read the ladder. Fair prices per alternate line — grade a book's alt quote against its rung.

Why do books shade alternate lines?

Because alternate ladders get less two-way action than the main line, books protect themselves with wider margins the further a rung sits from the market number. A derived fair ladder exposes exactly how much extra hold each rung carries.

Dynatyze Betting is analytics and education for people 21 and over. It is not a sportsbook: no wager is ever placed on Dynatyze — the tools help you find and price the best available bet elsewhere. If gambling stops being fun, help is free and confidential at 1-800-GAMBLER.