Betting Odds Explained: Decimal Odds, Margin, 1X2 and Accumulators

What do decimal odds tell you?

Decimal odds tell you the total return for each unit you stake, with the stake already counted. A KES 100 bet at 2.50 returns KES 250 if it wins: your KES 100 back plus KES 150 profit.

That is the whole formula. Return equals stake times odds, and profit equals the return minus the stake. A price of 1.40 on a strong favourite returns KES 140 from KES 100, so the profit is KES 40. A price of 6.00 on an outsider returns KES 600, a profit of KES 500.

Decimal odds never go below 1.01, because a price of 1.00 would return only the stake. When you see 1.05 on a heavy favourite, the bookmaker is telling you it rates the result as close to certain and will pay you five shillings for every hundred you risk.

This guide uses decimal odds throughout. If you meet another format, the conversion is short. Fractional odds of 5/4 mean a profit of 5 for every 4 staked, so the decimal price is 5 divided by 4, plus 1, which is 2.25. American odds of +125 mean a profit of 125 on a stake of 100, which is also 2.25. Negative American odds, such as -200, give the stake needed to win 100, so -200 equals 1.50.

How do you turn odds into a probability?

Divide 1 by the decimal odds. The result is the implied probability, the chance of the outcome that the price assumes.

Odds of 2.00 imply 1 divided by 2, or 50 percent. Odds of 4.00 imply 25 percent. Odds of 1.25 imply 80 percent. The lower the price, the more likely the bookmaker thinks the result is.

This conversion is the most useful habit a bettor can learn, because it lets you compare a price with your own view. Suppose you think a team wins three times in five, which is 60 percent. The fair price for that view is 1 divided by 0.6, about 1.67. If the bookmaker offers 1.80, the price is longer than your fair price and the bet has value on your numbers. If it offers 1.50, it does not, however confident you feel about the match.

Your view can of course be wrong. Implied probability does not tell you who will win; it tells you what the price is betting on.

What is the bookmaker’s margin, and how do you work it out?

The margin is the amount by which the implied probabilities of every outcome in a market add up to more than 100 percent. A fair market would add up to exactly 100. The excess is the bookmaker’s built-in edge.

Take a worked example, not a real fixture: Home v Away, priced at 2.10 for the home win, 3.30 for the draw and 3.60 for the away win.

The three probabilities add up to 105.7 percent, so the overround is 5.7 points. To find the fair odds, divide each implied probability by 1.057 to bring the total back to 100, then turn it back into odds. The home win would be about 2.22 without the margin instead of 2.10.

That gap looks small on one bet. Over a season of weekly bets it adds up, and it is the cleanest way to compare bookmakers on the same match. Two sites offering 2.10 and 2.20 on the same home win are not giving the same deal: one has quietly kept more for itself.

The same sum works on any market where the outcomes cover every possibility: over and under, both teams to score, or a two-way handicap. Add the implied probabilities, and whatever sits above 100 is what the bookmaker keeps on average. It is worth doing once for a correct-score market, where a dozen or more outcomes each carry a small slice of margin and the total can surprise you.

How does a 1X2 market work?

A 1X2 market is the three-way bet on a football match result after 90 minutes plus stoppage time. 1 is the home win, X the draw and 2 the away win. Extra time and penalty shoot-outs do not count, which matters in cup ties.

Because the draw is a real outcome, a 1X2 market always has three prices, and the draw is often the one bettors overlook. A draw priced between 3.00 and 3.50 implies roughly a 29 to 33 percent chance, which is far from an outside bet.

Two related markets remove the draw in different ways. Double chance covers two outcomes with one bet: 1X wins if the home side wins or draws, X2 if the away side wins or draws, and 12 if either side wins. The price is lower because you cover more. Draw no bet refunds your stake if the match is drawn, so it behaves like a two-way market on the remaining outcomes.

A small aside on the labels. Most Kenyan jackpots ask you to pick 1, X or 2 on every match in a list, so the same three letters decide both an ordinary single and a jackpot slip. The jackpot, though, pays from a fixed prize structure, not from multiplied odds, which is why it is covered in a separate guide.

How do accumulators multiply odds and the margin?

An accumulator, or acca, combines several selections in one bet, and the odds are multiplied together. Every selection must win; if one loses, the whole bet loses.

Take three worked selections at 1.50, 1.80 and 2.00. The combined price is 1.50 times 1.80 times 2.00, which is 5.40. A KES 100 stake returns KES 540 if all three win. That return is why accas are popular: three modest prices turn into one large one.

The margin is multiplied too. If each leg carries an overround of about 5.7 percent, three legs together carry roughly 1.057 times 1.057 times 1.057, which is about 1.18. In plain terms, the acca gives the bookmaker about three times the edge of a single bet on the same matches. Add more legs and the edge keeps growing while the chance of winning falls.

Accumulator bonuses, where a bookmaker adds a percentage to the winnings of a long acca, are designed with this arithmetic in mind. They can soften the extra margin, but they do not remove it. Check the terms that apply before counting on one.

How do Kenyan taxes change the odds you actually get?

In Kenya the price on the screen is not what your deposit earns, because excise duty of 5% comes off the money you deposit for betting. If you deposit KES 1,000 and stake all of it at 2.00, only KES 950 is staked, so measured against the deposit your effective price is 1.90.

A deduction is also withheld when the bookmaker pays you out. The rate and the base for sports bets are still read two ways by tax advisers; if 5% is applied to the whole return, the same bet works out at 1.80 against your deposit. The guide to betting tax in Kenya sets out which rules are confirmed and has a calculator for your own numbers.

This changes how you read value. A price that looks fair before tax can be poor value after it, and a bet at 1.10 on a heavy favourite can lose money even when it wins once both deductions are counted. The shorter the price, the bigger the share of the profit that tax takes.

Why are odds and markets not yet part of our scores?

Odds and markets is one of five criteria in our ranking, with a weight of 20%, but it is not rated for any bookmaker yet. A fair comparison needs a margin sample taken across the same matches at the same time of day, and that sample has not been collected.

Until it is, the scores rest on the criteria with data, and the odds criterion is shown as not rated. The method is set out in full on how we score bookmakers. In the meantime the table above is the tool: take the 1X2 prices of the same match at two bookmakers, add up the implied probabilities, and the lower total is the cheaper market on that day.