Compare Lines Calculator
Two spreads, two prices, one answer: which line is actually better.
Take the first line: -3 (-115)
It is worth about $3.47 more per $100 staked than -3.5 (-105). To break even with it, the other line would need a price of +103.
Advanced: model assumptions+
These are the two inputs the model actually runs on, and you can change them. Sigma is how far final margins scatter around the line. The multipliers say how much more often each exact margin occurs than a smooth curve would predict, which is what makes 3 and 7 expensive in football. Edits apply to the calculator above immediately and are not saved anywhere.
1.00 means no clustering at that margin. Anything above 1 means the number lands more often than a smooth curve predicts, so a half point across it costs more.
Both lines are priced against one shared margin model sitting midway between them, so neither number is treated as the true line. The output is a comparison of the two, not a claim that either one beats the market.
Pick a league, enter two spread-and-price combinations for the same side, and the calculator tells you which one is worth more, by how much, and what price the losing line would need to draw level.
Done with the math? Bet a real market.
These numbers are live on the BettorEdge marketplace right now, at prices set by bettors, not the house.
Related tools
Now get these prices for real.
The math is free. Better odds are on BettorEdge. Sign up for a shot at up to $100. No deposit needed.
How the Compare Lines Calculator works
Why a half point is not always a half point
Football margins pile up on 3 and 7 because of how scoring works, so moving a spread from -3 to -3.5 gives away far more than moving it from -10.5 to -11. Any tool that treats every half point as equal will tell you the wrong thing exactly where the money is. This one prices each number against the league's real margin clustering.
How to compare two spreads at different prices
Line shopping is rarely about a strictly better number. It is about whether a better number is worth the extra juice attached to it, or whether a cheaper price makes up for a worse number. The answer flips depending on which number you are crossing and which sport you are in.
NFL key numbers vs college football and basketball
The NFL has the sharpest key numbers, with 3 far and away the biggest and 7 next. College football clusters on the same numbers but flatter, because its margins scatter much wider. Basketball is close to a smooth curve, so half points there are worth roughly the same wherever you are on the board. Baseball and hockey barely move off 1.5.
Reading the compare lines calculator output
The verdict gives the better line and the gap in dollars per $100 staked. The break-even price is the number the losing line would need to be repriced at to match. If that price is available somewhere else, the two options are equivalent and you should take whichever is easier to get down.
NFL half point value chart
How many cents of price it is worth to move a favourite from -n to -(n+0.5), by league. This is the table that makes line shopping concrete: in the NFL, going from -3 to -3.5 is one of the most expensive half points on the board, while -11 to -11.5 is nearly free. Basketball, where margins are close to a smooth curve, has no comparable spikes at all.
| Move | NFL | CFB | NBA | CBB |
|---|---|---|---|---|
| -1 to -1.5 | 5¢ | 5¢ | 8¢ | 8¢ |
| -2 to -2.5 | 5¢ | 5¢ | 8¢ | 9¢ |
| -3 to -3.5key number | 17¢ | 10¢ | 9¢ | 9¢ |
| -4 to -4.5 | 6¢ | 5¢ | 8¢ | 8¢ |
| -5 to -5.5 | 5¢ | 5¢ | 8¢ | 8¢ |
| -6 to -6.5 | 7¢ | 6¢ | 8¢ | 8¢ |
| -7 to -7.5key number | 12¢ | 8¢ | 8¢ | 9¢ |
| -8 to -8.5 | 6¢ | 5¢ | 8¢ | 8¢ |
| -9 to -9.5 | 5¢ | 6¢ | 8¢ | 8¢ |
| -10 to -10.5 | 8¢ | 7¢ | 8¢ | 8¢ |
| -13 to -13.5 | 6¢ | 6¢ | 8¢ | 8¢ |
| -14 to -14.5 | 10¢ | 7¢ | 8¢ | 8¢ |
| -17 to -17.5 | 8¢ | 7¢ | 8¢ | 8¢ |
| -20 to -20.5 | 7¢ | 6¢ | 8¢ | 8¢ |
| -21 to -21.5 | 9¢ | 7¢ | 8¢ | 8¢ |
How this is modelled. Final margins are treated as a normal distribution around the line, reweighted by how often each margin actually occurs. The NFL weights come from the published 2000-2025 margin distribution, in which a 3-point margin lands about 15% of the time and a 7-point margin about 9%. College football clusters on the same numbers but flatter; basketball is close to normal with only a small lift at 3; baseball and hockey sit tight around 1 and 2. These are documented approximations rather than exact constants, and the model is deliberately a little conservative on the value of the 3. Treat the output as a well-grounded comparison, not a precise price.
How often each NFL margin of victory happens
These are the observed numbers the model above is built on, rather than a black box. Across the 2000 to 2025 seasons, almost one NFL game in seven ends with a 3-point margin, and 3, 6 and 7 together account for roughly 30% of all results. That concentration is the entire reason a half point across 3 costs so much more than a half point across 11.
| Margin of victory | Share of NFL games |
|---|---|
| 3 pointskey number | 14.97% |
| 7 pointskey number | 9.09% |
| 6 points | 6.10% |
| 10 points | 5.57% |
| 4 points | 4.88% |
| 14 points | 4.84% |
| 1 point | 4.13% |
| 2 points | 4.04% |
| 8 points | 3.79% |
| 5 points | 3.64% |
| 17 points | 3.30% |
| 21 points | 2.78% |
| 13 points | 2.73% |
| 11 points | 2.35% |
| 18 points | 2.30% |
| 20 points | 2.18% |
| 24 points | 2.17% |
| 16 points | 2.12% |
2000 to 2025 NFL regular season and playoffs. Margins outside the list above make up the remainder.
Working from a moneyline instead? Use the implied probability calculator. To see what a spread means as an outright win chance, use the win probability calculator, and to strip the juice from a two-way market use the no-vig calculator.
Frequently asked questions
Is -3 or -3.5 better in the NFL?+
-3 is materially better, and it is usually worth paying extra juice for. A 3-point margin is the single most common NFL result, so moving to -3.5 turns a large block of push outcomes into losses. Enter both prices above to see the exact gap.
Is buying a half point worth it?+
It depends entirely on which half point. Crossing 3 or 7 in football is worth a lot of cents; crossing 11 or 12 is worth very little. In basketball, where margins are close to normally distributed, half points are worth roughly the same across the board.
How do you compare two spreads at different prices?+
Work out the win, push and loss probability for each number, apply each price to those probabilities, and compare the resulting value. This calculator does that against a league-specific margin model, then reports the difference per $100 staked.
Does this work for MLB and NHL?+
It runs, but run lines and puck lines are almost always fixed at 1.5, so in practice you are comparing prices at the same number rather than different numbers. The comparison is still valid, it is just a simpler question.