Alternate Lines: Definition, Prices and How to Read Them
A ladder of numbers
A book's main line is the number where the over and under are priced close to even. Alternate lines move the number and re-price it. Raising the line makes the over harder to win, so it pays more; lowering it makes the over easier, so it pays less. Together they form a ladder of the same prop at many numbers.
The implied chance falls as the number rises, which is the point of the ladder. Read together, the rungs show what chance the book gives the player of reaching each number.
One-sided rungs keep the margin
Most alternate rungs are priced on the over only, so there is no under to pair with and the margin cannot be taken out. An over-only price reads a little higher than a fair one, so the site stars it. Two-sided prices near the main number can be de-vigged; one-sided rungs cannot.
Books also do not delete a number when they move off it, so a two-sided rung away from the main line can be a stale main line. The site keeps each rung's update time and leaves stale two-sided rungs out rather than guess.
Comparing an alternate with the main line
Because every rung has an implied chance, you can compare it with a player's own games at the same number. That is what the market curve on a prop card does: the books' chance of the over at each number they price, drawn beside his history over the same numbers. It is a description of prices and past games, not a forecast.
Questions and answers
- What is an alternate line?
- A different number for the same prop than the main line, with a price adjusted to match, such as 29.5 points at +190 when the main line is 24.5.
- Why do alternate lines pay more or less?
- A number that is harder to clear pays more because the book gives it a lower chance, and an easier number pays less. Each price implies a chance.
- Can you remove the vig from an alternate line?
- Only when both sides are priced. Most alternate rungs are over-only, so their implied chance keeps the margin and reads slightly high.
Read next
- Player prop lineA player prop line is the number a sportsbook posts for one player's stat in one game, such as 24.5 points, with a price on the over and a price on the under.
- Implied probabilityImplied probability is the chance a price says an outcome has, found by converting the odds, and it puts American, decimal and fractional prices on one 0 to 100% scale.
- No-vig oddsNo-vig odds, also called fair odds, are a two-sided price with the sportsbook's margin (the vig, or juice) taken out, so the two sides' chances add up to 100%.
- MiddleA middle is a gap between two sportsbooks' numbers on the same prop, such as one book's over 24.5 and another's under 26.5, where a result inside the gap wins both sides.
This page explains arithmetic and vocabulary. It does not recommend a bet, a side, an amount or a sportsbook, and the examples are illustrations. For information only, not betting advice. 21+ only. Gambling problem? Call or text 1-800-GAMBLER.