How to read decimal odds and implied probability in Kenya

Decimal odds are the single-number prices you see on a bet slip, such as 1.85 or 3.40. Each one answers two questions: how much a winning bet pays, and what chance the price implies. If the idea of a price is new to you, start with what betting odds are.

What does a decimal price tell you?

A decimal price is the total return for every 1 shilling staked if the bet wins. The return includes your stake. Profit is the return minus the stake.

So return = stake x odds, and profit = stake x (odds - 1). A price of 1.00 would only hand your stake back, which is why real prices sit above it.

Regulation 23(1) of the Gambling Control (Conduct of Gambling Operations) Regulations, 2026 requires a licensee to clearly display betting odds, rules and terms for each bet. Regulation 23(2) says a licensee shall not alter the terms of a bet after accepting it, except as the Act and the Regulations permit. The price on your accepted slip is the one that counts.

How do you convert decimal odds to implied probability?

1. Find the decimal price for the outcome, for example 1.80.
2. Divide 1 by the price: 1 / 1.80 = 0.5556.
3. Multiply by 100 to get a percentage: 55.6%.
4. Read the answer as the chance the price implies, not the true chance, because the bookmaker's margin is built in.

The rule also runs backwards. To find the decimal price that matches a probability, divide 1 by the probability written as a decimal. A 25% chance matches odds of 1 / 0.25 = 4.00.

Worked examples with a KES 100 stake

Illustrative example: at odds of 1.50, a KES 100 stake returns KES 150 if it wins, a profit of KES 50. The implied probability is 1 / 1.50 = 66.7%. The price implies this outcome about two times in three.

Illustrative example: at 2.00, the same stake returns KES 200, a profit of KES 100. The implied probability is 50%, the price of a fair coin toss before any margin.

Illustrative example: at 3.75, KES 100 returns KES 375, a profit of KES 275. The implied probability is 1 / 3.75 = 26.7%, a little more than one time in four.

Short prices still leave room to lose. Odds of 1.10 imply 90.9%, so about one such bet in eleven fails, which is why no betting tip can be sure.

The smallest online stake the law allows is KES 20, under section 71(1) of the Gambling Control Act, 2025. Illustrative example: KES 20 at 1.50 returns KES 30. The implied probability stays at 66.7%, because the stake does not change the price.

Decimal odds conversion table

Probabilities in the table are rounded to one decimal place. The odds converter gives the same figures for any price you type in and shows the margin of a whole market.

Why do the probabilities in one market add up to more than 100%?

Convert every outcome in a single market and add the results. The total comes out above 100%, and the excess is the bookmaker's margin, also called the overround. How the bookmaker's margin is built goes through it market by market.

Illustrative example: a home, draw and away market priced 2.10, 3.40 and 3.60 implies 47.6%, 29.4% and 27.8%. Those add up to 104.8%, so the margin is 4.8%.

To estimate the chances without the margin, divide each implied probability by the total. Here that gives about 45.4% for home, 28.1% for the draw and 26.5% for away, which together make 100%. Treat this as a rough method, because a bookmaker may not spread its margin evenly across outcomes.

How do fractional odds convert?

Fractional odds such as 6/4 show profit against stake: win 6 for every 4 staked. To turn them into decimal odds, divide the top number by the bottom one and add 1. For 6/4 that is 6 / 4 + 1 = 2.50.

For implied probability straight from a fraction, divide the bottom number by the sum of both numbers. For 6/4 that is 4 / (6 + 4) = 40%, the same answer as 1 / 2.50.

What the price on your slip does not show

Decimal odds cover only the stake and the return, and tax sits outside them. Paragraph 4A of the First Schedule to the Excise Duty Act charges excise on betting, and the Kenya Revenue Authority gives the rate as 5% of deposits from 1 July 2025. Section 36(b) of the Finance Act, 2026 changed that paragraph with effect from 1 July 2026, so it now speaks of money deposited "for betting purposes".

Illustrative example: a KES 1,000 deposit carries KES 50 of excise duty at 5%, whatever odds you later take. The duty depends on the deposit, not on the price or the result.

Which mistakes do people make when reading odds?

• Reading the return as profit. At 1.80 a KES 100 bet returns KES 180, but the profit is KES 80.
• Treating the implied probability as the true chance. It includes the margin, so it usually overstates the chance a little.
• Adding chances across different matches. When separate events sit on one slip, their probabilities multiply; they never add up.
• Assuming a short price is safe. A price of 1.25 implies 80%, which still means about one loss in every five such bets.
• Comparing a price with a different kind of number. A decimal price of 3.00 and a fraction of 3/1 are not the same: 3/1 is 4.00 in decimal form.

A single price also does not show how prices combine. A multibet multiplies the odds of its legs and multiplies their probabilities as well, as set out in accumulator (multibet) odds.