What is a half-point bet?

A half-point bet (or "buying points") is when the sportsbook lets you slide a spread or total by 0.5 in either direction in exchange for worse juice. Buying a half-point onto NFL key number 3 is the most valuable half-point move in football.

How do I calculate fair half-point juice?

Look up the historical probability delta for the integer crossed (NFL: 3 ≈ 9.5%, 7 ≈ 5.5%, 10 ≈ 1.5%, 14 ≈ 1.0%). The fair price is what the new line's implied probability suggests — the calculator runs this lookup automatically.

Is buying half-points +EV?

Almost always +EV when the buy crosses an NFL key number (3 in particular). Outside of key numbers, half-points typically cost more juice than they're worth in true probability gain.

Advanced

Half-Point Calculator

Price the juice on buying or selling 0.5 points across a spread or total. NFL key-number boost (3, 7, 10, 14) is calculated automatically.

New to this? Start with:Teaser Calculator

Quick start

Pick NFL or NBA
Enter the current spread/total and odds
Enter the target spread/total — see fair juice and key-number flag

Try buying onto NFL key number 3

Move from -3.5 at -110 down to -3 (buy onto key number 3). Fair juice ≈ -162.

Sport

odds format selector

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Current Line & Current Odds

Current Line

Enter American

Converted

Decimal

Fractional

Probability

American odds the sportsbook offers right now (e.g. -110).

Target Line

Pick a sport, enter the current line and odds, and a target line to see the fair juice.

How to Use the Half-Point Calculator

Pick the Sport (NFL or NBA). Enter the Current Line and the Current Odds the sportsbook is offering. Enter the Target Line — the new spread or total after the half-point move.

The calculator returns the fair American juice the new line should carry, the implied probability before and after, and a flag indicating whether the move crossed a key number.

Worked example: NFL spread at -3.5 priced at -110. Buy a half-point to move it down to -3. The crossed integer is 3, an NFL key number with a roughly 9.5% probability delta. The fair price for the new line is about -162 (about 60% implied vs 52.38% before). If the sportsbook charges less juice than the fair price, the buy is +EV.

How it works

Sportsbooks charge extra juice when you buy points across a key number. The calculator looks up the historical probability delta for the integer crossed (NFL 3, 7, 10, 14; NBA 4, 5, 7) and computes the fair price the new line should carry.

Pick sport — NFL and NBA have different key-number tables.
Enter current line and odds — Type the spread (e.g. -3.5) and the American odds the book is offering (e.g. -110).
Enter target line — The new line you want to buy or sell to (e.g. -3 to buy half a point onto the key number).

Related tools and guides

Use the teaser calculator for multi-leg point buys, the single-bet calculator for payout sanity checks, and the NFL key numbers guide for the strategy behind 3 and 7.

Strategy

Teaser Calculator

Price NFL and NBA teasers across point buys

Essentials

Single Bet Calculator

Calculate payouts for a single wager

Advanced

NFL Key Numbers Guide

Why 3 and 7 matter when buying or selling points

Half-Point Calculator FAQs

In the NFL, more games are decided by certain margins. Top key numbers are 3 (~9.5%), 7 (~5.5%), 10 (~1.5%), and 14 (~1.0%). Buying or selling half-points across these has an outsized effect on win probability.

Almost always when the buy crosses a key number — especially 3 in the NFL. Buying from -3.5 to -3 (or +2.5 to +3) is the most valuable half-point in football.

NBA key numbers are softer (4, 5, 7). Half-point buys in the NBA can still be valuable but probability deltas are smaller than NFL.

A teaser buys 6+ points on every leg at a fixed combined price. The half-point calculator prices the juice for buying just 0.5 points on a single bet — useful when the book lets you slide individual lines.