How Are In-Running Odds Calculated?

Gambling.com Editor

November 16th, 2016

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You know what’s it like: an early red card, an injury, a break of serve…these incidents can change the whole nature of a sports event. Outsiders suddenly become favourites and the most-backed selection suddenly looks very vulnerable. All of which has a huge impact on the odds. At least, it does now. Thanks to in-play betting.

In-play betting was created to offer punters an opportunity to wager on markets that are dynamic in nature, with key incidents helping to shape new prices 'in running'. It’s added an entirely different dimension to sports betting. But who is responsible for calculating in-running odds?

And how do specific events within matches dictate the level of fluctuation? The art of bookmaking is about minimising risk while producing prices that remain attractive to the betting community. This is sometimes easier said than done – especially with in-running betting, where the unforeseen can shift price points almost beyond recognition.

When that Third Division team takes the lead away from home against a Premier League side in the FA Cup, that sound you can hear is odds compilers across the land trying manfully to reset their prices.

What are In-Running Odds?

We all know about betting odds that are compiled prior to a ball being hit, kicked or potted, but what happens when the match has started? Technological advancements have facilitated in-play betting, with mobile punters having access to an ever-changing landscape of odds as a sporting event unfolds. The creative minds behind bookmakers are smart, and they recognised a new opportunity for leveraging additional profit.

In 'the old days', to coin a phrase, bets were taken prior to the start of an event and that was it. Now, in-play punters can place their wagers up until the final whistle is blown, the match-winning point converted or the final putt sunk. This presents opportunities – and risks – for a bookie, so pricing up their reactive markets accurately is essential.

The best example to use is that of a football match. So much can happen in the space of 90 minutes that the likely winner of the match can change numerous times within the length of the game. Team A may have been a heavy favourite prior to kick off, but what happens if they are a goal down at half time? Maybe their best player succumbs to an injury after 15 minutes?

Clearly, this harms their chances of winning and promotes the cause of their opponents. Live betting odds try to reflect these changes, and enable punters to find value hidden within the minutiae of a sporting event. As momentum fluctuates, so too do the markets.

How Are In-Running Odds Created?

To understand how in-running odds are created we must first understand how pre-match prices are calculated. As any sports fan knows, there is never an equal chance of certain events occurring. So if Manchester City are playing Hull City, there isn’t a 33% chance that the hosts will win, 33% the visitors and 33% the draw; we know that through implication.

We might put our own theoretical numbers on it: Manchester City might have a 60% chance of winning in our minds, the draw might come in 30% of times and Hull might get the win once out of ten. This, in essence, is how betting odds are calculated. Let’s price up that example in betting parlance:

Manchester City (Evens), Hull City (5/1), Draw (2/1)

These odds imply that Manchester City have a 1 in 2 chance of winning (50%), Hull a 1 in 6 (16.6%) and the draw comes in 1 in 3 (33.3%). Here’s the key difference though: if all three outcomes add up to 100%, then that is a ‘perfect market’, and the bookmakers won’t make any money!

So instead they run a book at around 108%, which assumes that no matter what the outcome of the event, the bookies will trouser a profit. With that in mind, we can see the basic building blocks from which in-play betting odds are devised. The actual events that cause them to fluctuate will differ from market to market, however the odds compiler will never veer from the bookmakers’ ‘over-round’, which is typically 7-10%.

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Who Creates In-Running Betting Odds?

The lucky individuals that get to compile in-running prices are called odds compilers or traders, and ultimately their first aim is to minimise the amount of risk attached to each event and market. They do this by accurately setting their prices according to the profit margin outlined above. But of course they still need to prepare prices that are enticing to the bettor.

Most punters with an appreciation of mathematics can weigh up whether certain sets of prices are fair and represent the actual possibility of the outcome occurring, and with a number of different odds comparison sites available these days – most of which are updated ‘in running’ – a punter has options at their disposal in seeking out the very best odds.

Those players interested in some live betting now that you've heard all about how in-running odds are created, browse our list of topnotch live betting sites to find the perfect bookie for your next live event. If you're looking for a recommendation from the list, check out NetBet's stellar live-betting section and start in-play betting today!