Implied Probability: How to Read Transfer Odds Easily

It takes 30 seconds to calculate implied probability, but when done right, it can tell you whether the hype around a signing is real or already priced in.

What Is Implied Probability?

Every set of transfer odds is a bookmaker's estimate of likelihood, translated into a number designed to ensure profit. When you reverse-engineer that number back into a probability, you get what traders call the implied probability - the market's collective belief about whether a deal will happen.

Implied probability equals 1 divided by the decimal odds, multiplied by 100 to give a percentage. So if a club is priced at 1.33 to sign a player, the percentage conversion is 1 ÷ 1.33 x 100, which gives you 75.2%. 

The market is saying that the transfer has roughly a three-in-four chance of completing. At 3.00, the implied probability is 33.3%.

However, these raw percentages are inflated by the bookmaker’s margin (overround). To correct this, traders use margin removal:

Convert each price into implied probability

• 1.80 → 1 ÷ 1.80 x 100 = 55.6%
• 2.10 → 1 ÷ 2.10 x 100 = 47.6%

Add them together:

55.6 + 47.6 = 103.2%

Remove the margin by normalising

• “Move” = (55.6 ÷ 103.2) x 100 = 53.9%
• “Stay” = (47.6 ÷ 103.2) x 100 = 46.1%

Erling Haaland to Manchester City Summer 2022

Erling Haaland to Manchester City Summer 2022

As late as February 2022, South African betting sites had Manchester City priced at around 4.33 to sign Haaland, an implied probability of just 23%. Chelsea were close behind at 5.00 (20% implied), with Real Madrid and Bayern Munich also active in the market. 

The reason for the uncertainty was Pep Guardiola. The manager had spent years publicly insisting he didn’t need a traditional striker. But what those odds couldn't fully capture was the impact of a R1.136 billion release clause set to activate in the summer of 2022.

Once activated, it narrowed the field. Dortmund couldn't hold out for the R3.329 billion fee they'd publicly floated. The clause was the mechanism, and the market, at 23%, had significantly underpriced it.

Those who identified that logic and backed City at 4.33 were value hunting. Haaland signed for City in May for R1.136 billion and went on to score 36 Premier League goals in his debut season, and the fee now looks like one of the bargains of the era.

Declan Rice to Arsenal Summer 2023

Declan Rice to Arsenal Summer 2023

Arsenal were installed as early favourites shortly after West Ham won the Europa Conference League in June 2023. With the club's chairman publicly acknowledging Rice would be allowed to leave and the player known to prefer a move to north London, bookmakers had Arsenal at around 1.30, an implied probability of 76.9%.

The market was turned on its head by Manchester City's sudden entry. When City submitted a R1.99 billion bid, which was rejected by West Ham, their odds compressed sharply, briefly pushing them toward near parity with Arsenal. A punter looking at the market in that moment would have seen City at roughly 2.27 (44% implied) versus a temporarily reduced Arsenal. The bookies were treating it as a two-horse race.

Then Arsenal placed their R2.33 billion third bid, and their odds moved to around 1.18, an implied probability of 84.6%. At that point, the movement itself was the signal and highlighted price accuracy. 

Rice signed for Arsenal days later, becoming the most expensive British player in history at the time. The market had called it with high accuracy from relatively early in the window.