Middle Calculator
Split evenly between both sides
How To Use This Calculator
Identify middle betting opportunities by entering spread or total lines from two different sportsbooks. The calculator shows if a middle exists, how wide the window is, and your potential profit or loss.
Input the line and odds for your first bet (e.g., Team A -3 at -110).
Input the opposite side line and odds from another book (e.g., Team B +5 at -110).
See the middle window, profit if both win, and worst-case loss. Enter a stake to see dollar amounts.
What is a Middle Bet?
A middle bet occurs when you bet both sides of a spread or total at different numbers across two sportsbooks, creating a window where both bets can win simultaneously.
For example, if Book 1 has Team A -3 and Book 2 has Team B +5, you can bet both. If Team A wins by exactly 4, both bets win. If the result falls outside that window, one wins and one loses — but because each side pays close to even money, your loss is small.
Middle Window = |Line2| - |Line1|Middle Opportunity Reference
Common spread gaps and approximate probabilities of the middle hitting in NFL and NBA games. Wider middles hit more often but are harder to find.
| Lines | Middle Size | Approx. Hit Rate (NFL) | Risk/Reward | Verdict |
|---|---|---|---|---|
| -3 / +4 | 1 pt | ~3-5% | Low | Marginal |
| -3 / +5 | 2 pts | ~5-8% | Moderate | Worth considering |
| -3 / +6 | 3 pts | ~8-12% | Good | Strong middle |
| -7 / +10 | 3 pts | ~8-12% | Good | Includes key numbers |
| -3 / +7 | 4 pts | ~10-15% | Excellent | Rare but very profitable |
Step-by-Step Example
You find an NFL game where Book 1 has Chiefs -3 (-110) and Book 2 has Bills +5 (-110). You want to bet a total of $200 ($100 each side).
Common Mistakes to Avoid
At -110 odds, you lose $9.09 every time the middle doesn't hit (per $100 side). This adds up. Make sure the middle window is wide enough to compensate for the vig cost on every non-middle outcome.
A 1-point middle only hits 3-5% of the time. You need approximately 20+ attempts before it hits once. Unless the odds are very favorable, narrow middles often lose money long term due to the vig.
Middle opportunities come from line discrepancies between books. The more sportsbooks you have accounts at, the more middles you will find. Check at least 3-4 books before placing a middle.
Unless you have a reason to weight one side, split your stake evenly. Unequal amounts increase your worst-case loss on one side without proportionally improving your middle profit.
Frequently Asked Questions
What is the difference between a middle and an arbitrage bet?
An arbitrage bet guarantees profit regardless of the outcome. A middle bet has a small loss most of the time but a large win when the result lands in the middle window. Middles are a calculated risk, while arbs are risk-free.
How often do middle bets actually hit?
It depends on the size of the middle window and the sport. A 2-point middle in NFL hits roughly 5-8% of the time. In NBA with higher-scoring games, similar point gaps can hit slightly more often. Key numbers like 3 and 7 in football boost hit rates.
Can I middle totals (over/under) as well as spreads?
Yes. If one book has Over 48.5 and another has Under 51.5, you have a 2-point middle on totals. The same math applies — you win both bets if the total lands at 49, 50, or 51.
What key numbers should I look for in football middles?
In NFL, 3 and 7 are the most common margins of victory. A middle that includes the number 3 (e.g., -2.5 / +3.5) or 7 (e.g., -6.5 / +7.5) has a higher chance of hitting because games frequently land on these margins.
Will sportsbooks limit me for middling?
Middles are less likely to trigger limits than pure arbitrage because you are betting both sides at different books. Sportsbooks generally view spread bettors more favorably than arbers. However, consistently sharp betting patterns can still lead to limits over time.
Should I adjust my stake based on middle width?
Yes. Wider middles justify larger stakes because they hit more often. For a 1-point middle, keep stakes small. For a 3+ point middle, you can size up. Think of it like any other edge — bet proportional to the expected value.
How do I find middle opportunities?
Compare lines across multiple sportsbooks for the same game. Look for games where the spread differs by 2+ points between books. Line movement creates the best middle windows — a team that opens at -3 and moves to -5 at some books may still be +3 at others.
Pro Tip: Target Key Numbers in Football
The most valuable middles in NFL betting include the numbers 3 and 7 — the two most common margins of victory. A middle from -2.5 to +3.5 or -6.5 to +7.5 has a significantly higher chance of hitting because so many games are decided by exactly a field goal or a touchdown. Pair this with our Arbitrage Calculator to compare odds across sportsbooks.