# How Do Betting Odds Work?

> How betting odds work, in plain English: decimal and fractional odds, converting odds to implied probability, and why bookmakers show different odds.

Source: https://oddsclass.com/learn/how_betting_odds_work/ · Publisher: OddsClass editorial team · Reviewed: 2026-11-06 · Language: en
> **Short answer:** Betting odds show two things: how much you get back if you win, and how likely the bookmaker thinks an outcome is. With decimal odds, your return is your stake multiplied by the odds. Lower odds mean a smaller return and a more likely outcome.

## Betting odds example: Gor Mahia vs AFC Leopards

Here is a simple 1X2 market. "1X2" means home win (1), draw (X) or away win (2).

| Outcome | Odds (example odds) | Return on KSh 100 | Profit on KSh 100 |
|---|---|---|---|
| Gor Mahia win (1) | 2.10 | KSh 210.00 | KSh 110.00 |
| Draw (X) | 3.20 | KSh 320.00 | KSh 220.00 |
| AFC Leopards win (2) | 3.60 | KSh 360.00 | KSh 260.00 |

Say you stake (the money you bet) KSh 100 on Gor Mahia at 2.10.

If the match ends 2–1 to Gor Mahia, you get KSh 100 × 2.10 = KSh 210. That is your KSh 100 back plus KSh 110 profit.

If the match ends in a draw or an AFC Leopards win, you lose the KSh 100.

## What are decimal odds?

Decimal odds are a single number that shows your total return for every 1 unit you stake. They are the most common format in Nigeria, Kenya, Ghana, South Africa, Uganda and Tanzania.

The formula is simple:

- **Return** = stake × odds
- **Profit** = return − stake

Example: GH₵10 at odds of 1.80 returns GH₵10 × 1.80 = GH₵18. Your profit is GH₵18 − GH₵10 = GH₵8.

The return always includes your stake. That is why decimal odds are never below 1.00.

## What are fractional odds, and how do you convert them to decimal?

Fractional odds show your profit compared with your stake, such as 5/2. You read 5/2 as "five to two". It means you win 5 units of profit for every 2 units you stake.

To convert fractional odds to decimal, divide the top number by the bottom number, then add 1.

5/2 becomes (5 ÷ 2) + 1 = 2.5 + 1 = 3.50.

| Fractional | Working | Decimal |
|---|---|---|
| 1/2 | (1 ÷ 2) + 1 | 1.50 |
| 1/1 (evens) | (1 ÷ 1) + 1 | 2.00 |
| 11/10 | (11 ÷ 10) + 1 | 2.10 |
| 6/4 | (6 ÷ 4) + 1 | 2.50 |
| 2/1 | (2 ÷ 1) + 1 | 3.00 |
| 5/2 | (5 ÷ 2) + 1 | 3.50 |

You add 1 because decimal odds include your stake. Fractional odds do not.

## How do you turn odds into implied probability?

Implied probability is the chance of an outcome that the odds suggest. To find it, divide 1 by the decimal odds, then multiply by 100.

Using the Gor Mahia example above:

- Gor Mahia win at 2.10: 1 ÷ 2.10 = 0.4762, so about 47.62%
- Draw at 3.20: 1 ÷ 3.20 = 0.3125, so 31.25%
- AFC Leopards win at 3.60: 1 ÷ 3.60 = 0.2778, so about 27.78%

This is the bookmaker's view, not a fact. Teams can and do beat these numbers. Read more in our guide to [implied probability](https://oddsclass.com/learn/implied_probability/).

## Why do odds differ between bookmakers?

Odds differ because each bookmaker sets its own prices and adds its own margin. The margin (the bookmaker's built-in profit) is the main reason.

Add up the three implied probabilities from the example:

47.62% + 31.25% + 27.78% = 106.65%

A fair book would add up to exactly 100 percent. The extra 6.65% is the margin. It means the odds are a little lower than the "fair" price on every outcome.

A bookmaker with a smaller margin offers slightly higher odds. Bookmakers also react to news and betting at different speeds. So one may show 2.10 while another shows 2.05 for the same team.

## What do low odds and high odds mean?

Low odds mean the bookmaker thinks an outcome is likely, so it pays less. High odds mean the outcome is less likely, so it pays more.

Here is a comparison with an R20 stake:

| Odds (example odds) | Implied probability | Return on R20 | Profit on R20 |
|---|---|---|---|
| 1.25 | 80.00% | R25.00 | R5.00 |
| 2.00 | 50.00% | R40.00 | R20.00 |
| 5.00 | 20.00% | R100.00 | R80.00 |

Low odds do not make a bet safe. At 1.25, the odds still suggest the outcome fails about 1 time in 5.

High odds are not "better value" by default either. A big return on a very unlikely event is still usually a loss. To check your own numbers, use our [payout calculator](https://oddsclass.com/tools/payout_calculator/).

## Common mistakes

- **Forgetting the stake is inside the return.** Odds of 2.10 on KSh 100 give KSh 110 profit, not KSh 210 profit.
- **Treating low odds as safe.** A 1.25 favourite can still lose.
- **Reading implied probability as the real chance.** It is the bookmaker's estimate, and it includes the margin.
- **Converting fractions wrongly.** Always add 1 after dividing. 2/1 is 3.00, not 2.00.
- **Ignoring price differences.** A small gap, like 2.05 vs 2.10, changes your return on every bet.

## Bet responsibly

Only stake money you can afford to lose. Set a deposit limit in your bookmaker account before you start. If betting stops being fun, read [where to get help](https://oddsclass.com/learn/gambling_help/).

## Related guides

- [How to calculate betting payout](https://oddsclass.com/learn/how_to_calculate_betting_payout/)
- [What is implied probability?](https://oddsclass.com/learn/implied_probability/)
- [What is an accumulator bet?](https://oddsclass.com/learn/accumulator_bet/)
- [What is a value bet?](https://oddsclass.com/learn/value_bet/)