When Was the Best Time to Bet on NFL Underdogs?

Great question. I loaded the NFL scores and betting data from 1979-2024 — about 11,500 games with spread data. Let me show you the underdog cover rate by season.

The data is striking. Underdogs have covered the spread more than 50% of the time in almost every season since 1979. The breakeven point for bettors (accounting for the standard -110 vig) is about 52.4% — and underdogs have consistently beaten that threshold. You can see some wild swings though, with cover rates ranging from about 50% to over 66%.

Let me pull the top 10 seasons ranked by underdog cover rate.

1993 was the holy grail — underdogs covered 66.2% of games. That's a massive edge. The late 1990s and early 2000s were especially lucrative, with 2002, 1995, 2001, and 1999 all appearing in the top 10. Interestingly, 2020 also makes the list at 61.1%, suggesting the edge hasn't completely disappeared.

Good thinking — let me aggregate by decade to see the bigger picture.

The 1990s were definitively the best decade for underdog bettors at 60.6% cover rate. The 1980s came in second at 58.1%. There's been a gradual decline since — the 2010s had the lowest edge at 56.9%, which suggests oddsmakers have gotten better at setting lines. But even at 56.9%, you're still above the breakeven threshold.

Let me simulate that. Assuming $100 per bet at standard -110 odds (win $100, lose $110).

You'd be up about $135,000 over 45 years. The growth was steepest during the 1990s and early 2000s — that's when the biggest gains accumulated. Notice the curve flattens somewhat after 2005, reflecting the tighter spreads in the modern era. But crucially, it never really dips — just three individual losing seasons in 46 years (2005, 2016, and 2024). The underdog edge has been remarkably consistent.