NFL Point spread: devig calculator
- Market
- 2-way
- Typical overround
- 4%–5%
- Sample overround
- 4.71%
- Worst-case probabilities are per-outcome minimums and do not add up to 100%.
| Outcome | Multiplicative | Additive | Powerk = 1.071 | Shinz = 0.047 | Worst case |
|---|---|---|---|---|---|
| Outcome 1 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 |
| Outcome 2 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 | 50.00%2.000 |
- Overround
- 4.71%
- Margin
- 4.50%
- Outcomes
- 2
Overround 4.71%
The point spread is priced at -110 on each side at most books, with the line rather than the price moving to balance action. Whole-number lines can push, which refunds the stake and breaks an arbitrage.
Overround in this market
NFL Point spread has 2 outcomes (
Favorite -3.5, Underdog +3.5). Bookmakers usually price it with an overround between 4% and 5%. Sharper books sit at the low end; recreational books and multi-way fields at the high end.
Worked example
Sample prices of 1.91 / 1.91 carry an overround of 4.71% (margin 4.50%). Multiplicative devigging gives fair probabilities of 50.0% / 50.0% and fair odds of 2.00 / 2.00. The calculator above starts from these prices and shows every method side by side.
| Outcome | Odds | Implied | Fair probability | Fair odds |
|---|---|---|---|---|
| Favorite -3.5 | 1.91 | 52.4% | 50.0% | 2.00 |
| Underdog +3.5 | 1.91 | 52.4% | 50.0% | 2.00 |
Method choice
In this 2-way market, with prices this close, the methods agree closely. Differences appear when one side is a heavy favourite; then the power and Shin columns are the ones to trust for the outsider's fair price.
Frequently asked questions
What is a normal overround for NFL Point spread?
Between 4% and 5% at most bookmakers. Lower means a sharper book; multi-way fields run higher.
Which devig method should I use for NFL Point spread?
With 2 outcomes priced close together the methods agree. When one outcome is a heavy favourite or the field is large, power or Shin better model where the margin sits; worst case gives the most conservative probability.
What are the fair odds for the sample prices?
The sample prices 1.91 / 1.91 carry an overround of 4.71%. Multiplicative devigging gives fair probabilities of 50.0% / 50.0% and fair odds of 2.00 / 2.00.
Can I use the fair probability to size a bet?
Yes: enter it with an offered price in the EV & Kelly calculator, or use the devig calculator's price-check panel, which reports edge and Kelly stake for each method.