NFL key numbers are the final winning margins that come up far more often than the rest, and the big ones are 3 and 7. Across 7,276 NFL games from 1999 to 2025, 15.1% were decided by exactly 3 points and 9.0% by exactly 7. That matters because a line of -3 and a line of -2.5 are not half a point apart in value. They can be worth very different prices. This guide shows how often each margin lands, what a half point is worth in decimal odds, and how to check a line on an Australian odds board.
With the AFL and NRL done until March, the NFL is one of the busiest markets on the board through to the Super Bowl. If footy is your usual sport, this is the one piece of NFL maths worth learning first.
What are NFL key numbers?
A key number is a winning margin that games finish on unusually often. In NFL scoring, a field goal is worth 3 and a converted touchdown is usually worth 7, so close games keep landing on those gaps.
Here is how often each margin came up across those 7,276 games (Deuces Cracked, 1999 to 2025):
| Final margin | Games | Share of all games |
|---|---|---|
| 3 | 1,100 | 15.12% |
| 7 | 657 | 9.03% |
| 6 | 436 | 5.99% |
| 10 | 401 | 5.51% |
| 4 | 355 | 4.88% |
| 14 | 355 | 4.88% |
| 1 | 303 | 4.16% |
| 2 | 295 | 4.05% |
| 8 | 271 | 3.72% |
| 5 | 260 | 3.57% |
| 17 | 260 | 3.57% |
| 9 | 117 | 1.61% |
Two things stand out. 3 lands about as often as 7 and 6 combined. And the margins next door to the key numbers are thin: 9 lands only 1.6% of the time, even though it sits between 7 and 10.
Has it changed since 2015?
A little. In 2015 the NFL moved the extra-point kick back to the 15-yard line, so more kicks miss and more teams go for two. ESPN found that since the change, 14.8% of games have been decided by exactly 3 points, with 7 next at 9%. Covers compared 2015 to 2023 with 2006 to 2014 and found 6 and 8 point games rose by 2.4%. So 3 and 7 are still on top, and 6 and 8 matter a bit more than they used to.
The 15% trap: it counts both teams
The 15% figure is easy to misread. It counts every game won by 3, by either team. If you take a favourite at -3, you only push when that team wins by exactly 3. The underdog winning by 3 is just a loss for you.
So for one side of a 3-point line, the push chance is closer to half the headline number. Covers takes the long-run rate of about 15.2% and halves it to 7.6% for exactly this reason. The worked example below uses a round 8%.
What a half point is worth in decimal odds
On an Australian odds board the NFL line market looks like this: Team A -3 at $1.91, Team B +3 at $1.91. Some bookmakers will move the line to -2.5 and shorten the price instead. The question is always the same: is the better line worth the shorter price?
Here is a worked example with invented numbers. It shows the method, not a view on any game.
Say the true chances for a 3-point favourite are:
- wins by 4 or more (covers -3): 46%
- wins by exactly 3 (push at -3): 8%
- anything else (wins by 2 or less, or loses): 46%
Option 1: -3 at $1.91. A push gives your stake back, so it adds nothing either way.
- Expected value per $1 = 0.46 x 0.91 minus 0.46 = -0.041, a loss of about 4.1 cents per dollar.
Option 2: -2.5. Now the win by exactly 3 counts as a win, so the favourite covers 54% of the time.
- Fair odds = 1 / 0.54 = $1.85
- The price that gives the same expected value as -3 at $1.91: 0.54 x (price minus 1) minus 0.46 = -0.041, so price = $1.78
So in this example, -2.5 is better than -3 at $1.91 if you can get it at about $1.78 or longer, and it is fair value at $1.85. A half point through 3 is worth roughly 13 cents of decimal price.
The same half point off a weak number
Now run the same sums on a 6-point favourite, where the push chance for one side is a smaller 3% (still invented):
- -6 at $1.91: covers 48.5%, push 3%, fails 48.5%. Expected value = -0.044 per $1.
- -5.5 covers 51.5%. Fair odds = $1.94. The price that matches -6 at $1.91 = $1.86.
Off 6 the half point is worth about 5 cents. Off 5 or 9, where far fewer games land, it is worth even less.
| Half point | One-side push chance (invented) | Fair price after buying | Break-even vs $1.91 |
|---|---|---|---|
| -3 to -2.5 | 8% | $1.85 | $1.78 |
| -6 to -5.5 | 3% | $1.94 | $1.86 |
The lesson: the same half point can be worth a lot or almost nothing. It depends entirely on how often games land on the number you are crossing.
Buying points usually costs more than it's worth
Some bookmakers let you "buy" half points for a shorter price. The long-run record is not kind. Action Network found that buying a half point on the five most common margins (3, 7, 10, 4 and 6) would have lost an extra 18.63 units since 2003. Off 10 and 6 the results were slightly positive, but the samples were small. Covers' own example of paying the equivalent of -120 to move from +2.5 to +3 calls it overpriced.
The cheaper half point is often the one another bookmaker is already offering. If one book has -3 and another has -2.5, compare them with the break-even method above instead of paying for points. Our guide to line shopping covers how to do this across books.
Key numbers in NFL totals
Totals (overs and unders) have key numbers too, but they are much weaker because both teams' scores add together.
- From 2003 to 2017, the most common combined scores were 41 (3.9%), 37 (3.8%) and 44 (3.8%). Since 2015, 43 has been the most common at 4.0%.
- Covers' 2014 to 2023 data shows key ranges of 36 to 37, 39 to 41, 43 to 51 and 54 to 55, rather than a few sharp spikes.
No single total lands much more than about 4% of the time, compared with about 15% for a 3-point margin. So a half point on a total is usually worth much less than a half point through 3 or 7 on the line.
How to use key numbers on an odds board
- Look at where the line sits. A move from -2.5 to -3, or from -6.5 to -7, is a big change. A move from -4.5 to -5 barely matters.
- Watch the price as well as the line. Bookmakers often keep a game on -3 and shift the price ($1.83 one side, $2.00 the other) rather than step off a key number. That price shift is the market moving.
- Compare across bookmakers. Line it up on an odds screen so you can see -3 at one book and -2.5 at another side by side.
- Strip the margin. Run both sides through a no-vig calculator to get the fair price before comparing it with what is on offer. Our guide to the vig explains the margin itself.
- Remember the push. At a whole number your stake comes back on a push. That has value, and it is why -3 at $1.91 can beat -2.5 at $1.75.
Key numbers also explain why some markets are priced the way they are. Teasers, for example, lean on moving lines through 3 and 7. Our teaser betting guide covers that, and point spread betting covers the basics of the line itself.
What key numbers don't tell you
Key numbers describe the history of all games. They do not tell you who will cover this weekend. A 3-point favourite's real chance of winning by exactly 3 depends on the teams, the total and the spread. A low total makes field-goal margins more likely; a high total spreads the margins out. Use the frequencies to judge what a half point is worth, not to pick a side. Even at a fair or better price, any single bet can lose, and short runs of results swing a long way.
Compare NFL lines before you bet
NFL lines are on the board every week through to the Super Bowl. BetBank's odds screen lines up NFL prices across bookmakers so you can see who is on -3 and who is on -2.5, and the calculators turn both prices into fair odds in a few seconds. Start a 7-day free trial and check the next NFL line you were going to bet before you place it.
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