What is an Underdog? Underdog in Betting Explained
Mike Goodpaster Last Verified
19/04/2026
What is an Underdog?
An underdog is a person or team who is not the favourite to win an event. In any match, league or competition there will one side that are not expected to win – but the beauty of sport is that there is always the chance that they can upset the odds and beat their more fancied opponent.
Underdogs can be found in football betting, or betting on other sports such as cricket, rugby and tennis.
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How is an Underdog used in Sports Betting?
Bookmakers offer prices, or odds, on the probability of a particular event occurring. For example, in a football match between Chelsea and Cardiff, Chelsea would be the favourites to win and might attract odds of around 1/5 for that to happen. It is less likely, given the talent and players available, that Cardiff win the match. Therefore the odds would reflect that. Cardiff might be around 10/1 to win the match.
In this event Cardiff are the underdog as there is less likelihood of them winning. The attraction for bettors here is that selecting Cardiff to win has the potential of paying out much more than selecting Chelsea. With these odds a £10 bet on Chelsea would return £12 – only £2 profit. But the same bet on Cardiff would return £110. That is why underdogs are repeatedly selected for bets.
Did You Know...
Underdogs win a relatively fair amount of the time in sports like football or rugby as the team element of the sport creates more variables to an event. But one of the biggest underdogs in sporting history was boxer Buster Douglas who was a 42/1 shot at beating the all-conquering Mike Tyson at the height of his powers. Douglas stopped Tyson in the 9th round and became (briefly) champion of the world.
