Football managers often have half-baked ideas on their tactics or new players to sign, but they never instruct their team to score half-a-goal because, well, that’s an impossibility.
That’s one of the reasons why punters get so confused about the .5 goals lines that the bookmakers offer. You can’t score half a goal, that’s a given.
But when you understand the logic of the 0.5, 1.5, 2.5 and so on goal line, and what the numbers mean, it becomes so easy to follow and unearths a potentially profitable betting market for savvy punters.
It’s the sort of thing you only need to learn once, and it’s so simple that you can never forget how it works, so this article will hopefully unlock a new betting market for anyone who has never used it before.
How Does the .5 Goals Market Work?
The bookies use .5 goals as it makes it easier for punters to understand the over and under lines.
So, let’s look at an example. Liverpool are playing Manchester City at Anfield, and the bookmakers are offering odds of 8/11 on Over 2.5 Goals. What does this mean?
Let’s break it down. If three or more goals are scored, then the game has gone ‘over’ the 2.5 line. If there are two goals or fewer, it has stayed ‘under’ the line.
The game can’t end with 2.5 goals scored, so the bet will definitely win or lose.
The same logic applies to all of the other ‘half goals’ that the bookmakers price up.
So, over 1.5 goals pays out when there are two or more goals in a game – in this case, the unders line wins if the game finishes 1-0 to either team or 0-0.
For the over 3.5 goals line, we’re looking for games with stacks of goals – four or more, to be precise. That includes final scores like 2-2, 3-1, 2-3 and so on. For under 3.5 goals, you’ve guessed it, three or less goals is the order of the day. Here, we’ll be cheering on scorelines like 0-0, 1-0, 1-1, 2-0, 1-2 and even 3-0 to either side. All would see the unders line pay out.
Using Goals Data In Our Betting
The chances are that, if you follow a particular league or competition closely, you will already have some idea of how each team plays – whether they attack and get plenty of bodies forward, or if they are conservative and defend deep with players behind the ball.
Clearly, the strategy of each team determines whether they are good candidates for the overs or unders side of the .5 line. From a betting perspective, it’s worth taking a look at the data, so here’s how the Premier League 2021/22 season looked after 22 rounds of matches:
| Club | Over 0.5 | Over 1.5 | Over 2.5 | Over 3.5 |
|---|---|---|---|---|
| Arsenal | 90% | 76% | 52% | 38% |
| Aston Villa | 100% | 81% | 62% | 29% |
| Brentford | 96% | 78% | 57% | 26% |
| Brighton | 86% | 77% | 23% | 14% |
| Burnley | 75% | 65% | 40% | 35% |
| Chelsea | 96% | 83% | 50% | 25% |
| Crystal Palace | 95% | 86% | 64% | 36% |
| Everton | 95% | 81% | 62% | 38% |
| Leeds Utd | 95% | 76% | 57% | 38% |
| Leicester City | 100% | 85% | 70% | 45% |
| Liverpool | 100% | 86% | 77% | 59% |
| Manchester City | 96% | 70% | 52% | 35% |
| Manchester Utd | 100% | 74% | 48% | 39% |
| Newcastle Utd | 100% | 91% | 50% | 41% |
| Norwich City | 86% | 77% | 59% | 18% |
| Southampton | 91% | 73% | 55% | 45% |
| Tottenham | 95% | 70% | 55% | 20% |
| Watford | 95% | 68% | 50% | 36% |
| West Ham Utd | 92% | 71% | 58% | 42% |
| Wolverhampton | 86% | 43% | 24% | 10% |
Even at first glance, we can get a good idea of how each team goes about their business, plus the likelihood of the overs/unders lines paying out for any given fixture.
Using a very crude formula, we can calculate how likely a game is to go over or under a specified line. Let’s say Manchester United are playing Southampton. We use the data to note that United go over the 2.5 goals mark in 48% of their games, whereas for the Saints it’s 55%. If we average out the two, we could say there’s a 51.5% of this game finishing with three or more goals scored. However, in this imaginary scenario let’s imagine that both teams have key defensive players out injured, so we will adjust it to 52%.
As we know, percentages can be used as a way of calculating implied probability, which we can then convert to fair odds that the bookies might offer (forgetting, of course, the over round they build in to their prices).
So, in this game:
- Implied probability of Over 2.5 Goals = 52%
- Fair odds = 1.92 (around 9/10)
Now, we head to our preferred betting site/app, and look up the Over 2.5 Goals odds. We find that this is priced at 1.73 (or 8/11), and so on this occasion we aren’t getting value, because our calculated probability is lower than that being offered by the bookies.
So, is there value in the Under 2.5 Goals market? Let’s run the numbers again. This time we are saying that there’s a 48% of there being two or fewer goals – the opposite of the equation given that we think there’s a 52% of the ‘overs’ landing.
- Implied probability of Under 2.5 Goals = 48%
- Fair odds = 2.08 (around 11/10)
- Bookie odds = 2.10 (or 11/10)
And so we have calculated that the under 2.5 goals line is the value play here, as the bookies are offering us better odds – albeit marginally – than we have calculated as fair.
Of course, this is a system that requires far more inputs – team news, form of the two sides, home advantage, weather, upcoming fixtures etc – for it to be considered an accurate strategic approach. But hopefully you can see how the data can shape your over/under .5 goals bets.
Over/Under 2.5 Goals vs Correct Score
If we have a particularly strong feeling about the number of goals that are going to be scored in a game, is it more profitable to back the correct score market instead?
The answer, invariably, is no.
Let’s take 0.5 goals first. If you back under 0.5, you are basically backing 0-0 – the odds are the same. If you back 0.5 goals, you would need to Dutch around a dozen scorelines to cover most, but not all, of the potential scorelines.
The 1.5 goals line becomes interesting when you are expecting a low scoring affair, and so would normally back the unders. Let’s run the numbers of under 1.5 goals and the three correct score bets that could make this happen – 0-0, 1-0 and 0-1 – from that Man Utd vs Southampton game:
- £10 on Under 1.5 Goals = £33 profit
- £3.11 on 0-0, £4.76 on 1-0 and £2.13 on 0-1 = £30.45 profit on any
When we try to cover every possibility, we can see that the odds are skewed to make the correct score bets unprofitable.
The only way we can make the system work is if we miss out some of the possibilities. Let’s take a look at a potentially one-sided contest: Man City vs Brentford. Here, the over 2.5 goals line is priced at 4/9, but sensing a heavy Man City victory we can play just a few of the available correct score options:
- £10 on Over 2.5 Goals = £4.44 profit
- £4.42 on 3-0, £2.21 on 3-1 and £3.38 on 4-0 = £18.70 profit on any
So we can see how backing selected correct scores can be a more profitable avenue than the overs line – around 400% more, in this example. But our risk is that we only have three scorelines covered, and although we could hedge in play by backing more, we soon start to erode our profit margin.