Underdog Betting Explained: Real Examples, Odds and Risks

An underdog is a team or athlete that bookmakers consider less likely to win than their opponent. Bookmakers offer higher odds on an underdog to win than on the opposing team or athlete. The opposite of an underdog is a favorite — the side expected to win.

Underdogs are sometimes described as outsiders. Although the terms overlap, there is a subtle difference:

• Underdog — a team or athlete considered less likely to win a particular match. Even a strong team can be the underdog when facing a stronger opponent.
• Outsider — a competitor considered unlikely to win an event or competition, particularly when there are multiple contenders.

For example, a club sitting fifth in a 20-team league is not one of the league’s weakest sides. However, it could easily be the underdog in an away match against the league leaders.

The term “underdog” can be used in the context of both individual matches and entire tournaments:

• In an individual match, a team may be the underdog against a stronger opponent but enter its next game as the favorite.
• In a tournament or title race, a team with very little chance of winning the competition may be described as a long shot. For example, a newly promoted club could be considered a long shot for the league title.

In other words, a team near the bottom of the standings is usually an underdog in the title race, but it can still be the favorite in an individual match.

How to Identify an Underdog from the Odds

The easiest way to identify an underdog is to check the bookmaker’s odds.

Consider a football match between two teams:

• Team A to win — odds of 1.20.
• Team B to win — odds of 4.00.

Team A is the favorite, while Team B is the underdog.

There is no specific odds threshold at which a team becomes an underdog. What matters is that its odds of winning are higher than those of its opponent.

For illustrative purposes, underdogs can be grouped into three broad categories based on their betting odds:

Here’s an example of underdog odds from bet365:

Heavy underdog: Aston Villa to win at odds of 8.50 (Full-Time Result)

Betting on an Underdog: Payout Example

Suppose you place a $10 bet on an underdog to win at decimal odds of 4.00.

If the bet wins, your net profit is $30 — three times your original stake.

Ways to Bet on Underdogs: Match Winner, Handicap and Double Chance

Backing an underdog to win is not the only option. Bettors can also consider markets such as positive handicaps and double chance bets. These markets allow a bet to win even if the underdog fails to win the match, although the odds are generally lower.

In the following football examples, all bets are settled on the result after regular time — 90 minutes plus stoppage time.

For example, if the favorite wins 1–0, a +1.5 handicap bet on the underdog would win, while bets on an away win (2) and double chance (X2) would lose. If the match finishes 1–1, both the +1.5 handicap and X2 double chance bets would win.

The more potential outcomes a bet covers, the lower its odds will generally be. However, handicap and double chance bets do not necessarily offer better value than backing the underdog to win. That depends on the odds offered and the probability of each outcome.

How Often Do Underdogs Win?

Underdogs regularly pull off surprise victories, but upsets are considerably more common in some sports than in others.

For example, data compiled by Covers for the period from 2021 through July 15, 2026, shows that underdog win rates vary across major US sports leagues.

Research supports this distinction. In some sports, indiscriminately backing underdogs results in greater losses than betting on favorites.

For instance, an analysis of 39,886 ATP matches played between 2010 and 2025 found that bets on underdogs produced an average return on investment (ROI) of −5.6%, compared with −2% for bets on favorites.

Of course, extraordinary upsets do happen. One of the most famous examples is Leicester City, which entered the 2015/16 English Premier League season as one of the biggest outsiders in the title race. Bookmakers offered staggering odds of 5,000/1 (5,001.00 in decimal format) on Leicester winning the league. Against all expectations, the club went on to become Premier League champions.

Stories like Leicester’s are memorable precisely because they are so rare.

How to Tell Whether an Underdog Bet Offers Value

Suppose a bookmaker offers odds of 4.00 on an underdog to win. That translates into an implied probability of 25%, before adjusting for the bookmaker’s margin. In practical terms, at those odds, you would need to win one in four bets on average just to break even over the long run, before taxes.

The same principle can be used to calculate the break-even win rate for other odds.

These percentages show the proportion of bets that must win to break even, not the actual probability of a team winning.

Bookmakers often build a larger margin into longer odds. As a result, the 25% implied probability calculated from odds of 4.00 does not necessarily reflect an underdog’s true chances of winning. The actual probability may be lower.

Now consider two scenarios:

• The underdog has a 20% chance of winning. Odds of 4.00 are too short for that probability. Even substantial payouts from occasional wins would not compensate for the frequent losses over time.
• The underdog has a 30% chance of winning. At odds of 4.00, the bet has positive expected value because the break-even win rate is only 25%.

These are hypothetical examples that assume the probabilities have been estimated correctly.

In sports betting, wagers that offer favorable odds relative to the true probability of an outcome are known as value bets.

But this raises the most important question: How can you tell whether an underdog’s true chances are better than the bookmaker’s odds suggest?

When analyzing a match, bettors typically consider recent team form, injuries to key players, home advantage and other relevant factors. However, bookmakers also account for these factors when setting their odds. As a result, even a convincing case for an underdog does not automatically make a bet good value.

Comparing odds across different bookmakers can also help. Assuming the same stake and settlement terms, higher odds mean a larger potential payout.

Ultimately, though, what matters most is whether the available odds accurately reflect the underdog’s chances of winning. Even seemingly attractive odds can represent poor value if the team’s actual probability of victory is too low.

Pros and Cons of Betting on Underdogs

The defining feature of betting on underdogs is the combination of higher potential payouts and lower win probabilities.

A single winning bet can offset several losses, but extended losing streaks are far from unusual.

According to Gambling Park’s calculations, if each bet has a 25% chance of winning, the probability of experiencing at least one streak of 15 consecutive losses across 500 independent wagers is approximately 82%.

This makes chasing losses particularly dangerous. Increasing stakes after each losing bet in an attempt to recover previous losses can quickly wipe out a betting bankroll, especially during a prolonged losing streak.

One way to limit potential losses is to keep stakes small and consistent. For example, with a $1,000 bankroll, a stake of 1% of your bankroll would be $10. This approach reduces the impact of any single losing bet, but it does not protect against losses over the long term.

More you might find interesting:

• System Bets Explained
• What Are Prop Bets
• Losing Streak in Sports Betting
• Clean Sheet in Football Betting
• Stake in Betting Explained
• Push in Sports Betting

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