NFL Underdogs Against the Spread, 1999–2026
Data and method
- Source
- nflverse game data: every National Football League (NFL) regular-season game from 1999, with point spread and, from 2006, moneyline prices. One line per game, broadly the market closing line.
- Underdog
- The team receiving points on the spread. Games with a spread of zero (pick'em) are excluded.
- Cover
- The underdog's final margin beats the spread. Pushes (margin exactly equal to the spread) are excluded from cover rates and returns.
- Against the spread (ATS)
- Results measured against the point spread rather than the straight-up winner.
- Return at -110
- Profit or loss per unit staked at standard -110 pricing (risk 110 to win 100). Break-even cover rate is 52.38%.
- 95% confidence interval
- Range for the true cover rate, using the normal approximation to the binomial distribution.
- p-value
- Exact binomial test: probability of a cover rate this high or higher if the true rate equalled the stated value.
- Weeks
- “Weeks 1–9” is treated as the first half of the season. 2026 contains only the weeks played to the data date.
Underdogs against the spread: all subsets
Every underdog subset tested, 1999–2026.
| Subset | Won–Lost | Bets | Cover rate | 95% confidence interval | Return at -110 |
|---|---|---|---|---|---|
| All underdogs, all weeks | 3473–3323 | 6,796 | 51.1% | 49.9% – 52.3% | -2.4% |
| Underdogs, weeks 1–9 | 1821–1678 | 3,499 | 52.0% | 50.4% – 53.7% | -0.6% |
| Underdogs, weeks 10+ | 1652–1645 | 3,297 | 50.1% | 48.4% – 51.8% | -4.3% |
| Underdogs, weeks 1–4 | 881–784 | 1,665 | 52.9% | 50.5% – 55.3% | +1.0% |
| Home underdogs, weeks 1–9 | 615–605 | 1,220 | 50.4% | 47.6% – 53.2% | -3.8% |
| Away underdogs, weeks 1–9 | 1206–1073 | 2,279 | 52.9% | 50.9% – 55.0% | +1.0% |
| Underdogs +0.5 to +3, weeks 1–9 | 692–641 | 1,333 | 51.9% | 49.2% – 54.6% | -0.9% |
| Underdogs +3.5 to +6.5, weeks 1–9 | 636–617 | 1,253 | 50.8% | 48.0% – 53.5% | -3.1% |
| Underdogs +7 to +9.5, weeks 1–9 | 308–261 | 569 | 54.1% | 50.0% – 58.2% | +3.3% |
| Underdogs +10 or more, weeks 1–9 | 185–159 | 344 | 53.8% | 48.5% – 59.0% | +2.7% |
| Underdogs, weeks 1–9, 1999–2005 | 445–413 | 858 | 51.9% | 48.5% – 55.2% | -1.0% |
| Underdogs, weeks 1–9, 2006–2012 | 471–417 | 888 | 53.0% | 49.8% – 56.3% | +1.3% |
| Underdogs, weeks 1–9, 2013–2019 | 471–436 | 907 | 51.9% | 48.7% – 55.2% | -0.9% |
| Underdogs, weeks 1–9, 2020–2026 | 434–412 | 846 | 51.3% | 47.9% – 54.7% | -2.1% |
Weeks 1–9 underdogs by season
First-half underdog results for each season. 13 of 27 complete seasons finished above the 52.38% break-even rate.
| Season | Won–Lost | Bets | Cover rate | 95% confidence interval | Return at -110 |
|---|---|---|---|---|---|
| 1999 | 69–52 | 121 | 57.0% | 48.2% – 65.8% | +8.9% |
| 2000 | 63–59 | 122 | 51.6% | 42.8% – 60.5% | -1.4% |
| 2001 | 61–59 | 120 | 50.8% | 41.9% – 59.8% | -3.0% |
| 2002 | 74–50 | 124 | 59.7% | 51.0% – 68.3% | +13.9% |
| 2003 | 59–66 | 125 | 47.2% | 38.4% – 56.0% | -9.9% |
| 2004 | 67–58 | 125 | 53.6% | 44.9% – 62.3% | +2.3% |
| 2005 | 52–69 | 121 | 43.0% | 34.2% – 51.8% | -18.0% |
| 2006 | 67–60 | 127 | 52.8% | 44.1% – 61.4% | +0.7% |
| 2007 | 67–58 | 125 | 53.6% | 44.9% – 62.3% | +2.3% |
| 2008 | 64–63 | 127 | 50.4% | 41.7% – 59.1% | -3.8% |
| 2009 | 63–64 | 127 | 49.6% | 40.9% – 58.3% | -5.3% |
| 2010 | 72–55 | 127 | 56.7% | 48.1% – 65.3% | +8.2% |
| 2011 | 63–62 | 125 | 50.4% | 41.6% – 59.2% | -3.8% |
| 2012 | 75–55 | 130 | 57.7% | 49.2% – 66.2% | +10.1% |
| 2013 | 61–69 | 130 | 46.9% | 38.3% – 55.5% | -10.4% |
| 2014 | 64–66 | 130 | 49.2% | 40.6% – 57.8% | -6.0% |
| 2015 | 70–58 | 128 | 54.7% | 46.1% – 63.3% | +4.4% |
| 2016 | 65–64 | 129 | 50.4% | 41.8% – 59.0% | -3.8% |
| 2017 | 65–60 | 125 | 52.0% | 43.2% – 60.8% | -0.7% |
| 2018 | 70–62 | 132 | 53.0% | 44.5% – 61.5% | +1.2% |
| 2019 | 76–57 | 133 | 57.1% | 48.7% – 65.6% | +9.1% |
| 2020 | 77–56 | 133 | 57.9% | 49.5% – 66.3% | +10.5% |
| 2021 | 77–58 | 135 | 57.0% | 48.7% – 65.4% | +8.9% |
| 2022 | 74–57 | 131 | 56.5% | 48.0% – 65.0% | +7.8% |
| 2023 | 59–69 | 128 | 46.1% | 37.5% – 54.7% | -12.0% |
| 2024 | 63–73 | 136 | 46.3% | 37.9% – 54.7% | -11.6% |
| 2025 | 61–74 | 135 | 45.2% | 36.8% – 53.6% | -13.7% |
| 2026 (partial) | 23–25 | 48 | 47.9% | 33.8% – 62.0% | -8.5% |
Moneyline underdogs, weeks 1–9
Underdogs backed to win outright at the quoted moneyline price, 2006–2026. Ties returned as stake back.
2,584Bets
35.3%Win rate
-0.8%Return on stake
±2.8%Standard error of return
Weeks 1–4 underdogs: significance tests
Weeks 1–4 underdogs, 1999–2026: 881–784 (52.9% of 1,665 bets). Tests against two null hypotheses.
| Null hypothesis (true cover rate) | One-sided p-value | Two-sided p-value |
|---|---|---|
| 50.00% (no underdog bias) | 0.009 | 0.019 |
| 52.38% (break-even at -110) | 0.341 | 0.677 |
Weeks 1–4 underdogs by season, 2016–2026
Season-by-season results for the last ten complete seasons and the current season, with multi-season windows. p-values are one-sided.
| Season / window | Won–Lost | Bets | Cover rate | 95% confidence interval | Return at -110 | p-value vs 50% | p-value vs 52.38% |
|---|---|---|---|---|---|---|---|
| 2016 | 33–30 | 63 | 52.4% | 40.0% – 64.7% | +0.0% | 0.401 | 0.551 |
| 2017 | 34–27 | 61 | 55.7% | 43.3% – 68.2% | +6.4% | 0.221 | 0.347 |
| 2018 | 33–29 | 62 | 53.2% | 40.8% – 65.6% | +1.6% | 0.352 | 0.498 |
| 2019 | 38–24 | 62 | 61.3% | 49.2% – 73.4% | +17.0% | 0.049 | 0.100 |
| 2020 | 32–31 | 63 | 50.8% | 38.4% – 63.1% | -3.0% | 0.500 | 0.648 |
| 2021 | 38–26 | 64 | 59.4% | 47.3% – 71.4% | +13.4% | 0.084 | 0.160 |
| 2022 | 36–25 | 61 | 59.0% | 46.7% – 71.4% | +12.7% | 0.100 | 0.182 |
| 2023 | 29–30 | 59 | 49.2% | 36.4% – 61.9% | -6.2% | 0.603 | 0.735 |
| 2024 | 37–26 | 63 | 58.7% | 46.6% – 70.9% | +12.1% | 0.104 | 0.189 |
| 2025 | 28–36 | 64 | 43.8% | 31.6% – 55.9% | -16.5% | 0.870 | 0.934 |
| 2026 (weeks 1–4 to date) | 23–25 | 48 | 47.9% | 33.8% – 62.0% | -8.5% | 0.667 | 0.778 |
| 2016–2025 | 338–284 | 622 | 54.3% | 50.4% – 58.3% | +3.7% | 0.017 | 0.174 |
| 2017–2026 | 328–279 | 607 | 54.0% | 50.1% – 58.0% | +3.2% | 0.026 | 0.219 |
| 1999–2015 | 520–475 | 995 | 52.3% | 49.2% – 55.4% | -0.2% | 0.082 | 0.543 |
All subsets with a positive return
Every subset, window and single season from the tables above that finished with a positive return at -110.
| Subset | Won–Lost | Bets | Cover rate | 95% confidence interval | Return at -110 |
|---|---|---|---|---|---|
| Underdogs, weeks 1–4 | 881–784 | 1,665 | 52.9% | 50.5% – 55.3% | +1.0% |
| Away underdogs, weeks 1–9 | 1206–1073 | 2,279 | 52.9% | 50.9% – 55.0% | +1.0% |
| Underdogs +7 to +9.5, weeks 1–9 | 308–261 | 569 | 54.1% | 50.0% – 58.2% | +3.3% |
| Underdogs +10 or more, weeks 1–9 | 185–159 | 344 | 53.8% | 48.5% – 59.0% | +2.7% |
| Underdogs, weeks 1–9, 2006–2012 | 471–417 | 888 | 53.0% | 49.8% – 56.3% | +1.3% |
| 2016–2025 | 338–284 | 622 | 54.3% | 50.4% – 58.3% | +3.7% |
| 2017–2026 | 328–279 | 607 | 54.0% | 50.1% – 58.0% | +3.2% |
| Underdogs, weeks 1–4, 2017 | 34–27 | 61 | 55.7% | 43.3% – 68.2% | +6.4% |
| Underdogs, weeks 1–4, 2018 | 33–29 | 62 | 53.2% | 40.8% – 65.6% | +1.6% |
| Underdogs, weeks 1–4, 2019 | 38–24 | 62 | 61.3% | 49.2% – 73.4% | +17.0% |
| Underdogs, weeks 1–4, 2021 | 38–26 | 64 | 59.4% | 47.3% – 71.4% | +13.4% |
| Underdogs, weeks 1–4, 2022 | 36–25 | 61 | 59.0% | 46.7% – 71.4% | +12.7% |
| Underdogs, weeks 1–4, 2024 | 37–26 | 63 | 58.7% | 46.6% – 70.9% | +12.1% |
| Underdogs, weeks 1–9, 1999 | 69–52 | 121 | 57.0% | 48.2% – 65.8% | +8.9% |
| Underdogs, weeks 1–9, 2002 | 74–50 | 124 | 59.7% | 51.0% – 68.3% | +13.9% |
| Underdogs, weeks 1–9, 2004 | 67–58 | 125 | 53.6% | 44.9% – 62.3% | +2.3% |
| Underdogs, weeks 1–9, 2006 | 67–60 | 127 | 52.8% | 44.1% – 61.4% | +0.7% |
| Underdogs, weeks 1–9, 2007 | 67–58 | 125 | 53.6% | 44.9% – 62.3% | +2.3% |
| Underdogs, weeks 1–9, 2010 | 72–55 | 127 | 56.7% | 48.1% – 65.3% | +8.2% |
| Underdogs, weeks 1–9, 2012 | 75–55 | 130 | 57.7% | 49.2% – 66.2% | +10.1% |
| Underdogs, weeks 1–9, 2015 | 70–58 | 128 | 54.7% | 46.1% – 63.3% | +4.4% |
| Underdogs, weeks 1–9, 2018 | 70–62 | 132 | 53.0% | 44.5% – 61.5% | +1.2% |
| Underdogs, weeks 1–9, 2019 | 76–57 | 133 | 57.1% | 48.7% – 65.6% | +9.1% |
| Underdogs, weeks 1–9, 2020 | 77–56 | 133 | 57.9% | 49.5% – 66.3% | +10.5% |
| Underdogs, weeks 1–9, 2021 | 77–58 | 135 | 57.0% | 48.7% – 65.4% | +8.9% |
| Underdogs, weeks 1–9, 2022 | 74–57 | 131 | 56.5% | 48.0% – 65.0% | +7.8% |