What do the odds look like?
Odds of 2.20 and 3.60 are two numbers; which is likelier is obvious, but how much likelier is not. Put them on a wheel and the answer is a picture. Press SPIN!:
The wheel as published is a football match at 2.20, 3.60 and 3.70 – a home win at about 45 per cent, a draw at 28 and an away win at 27:
From odds to a weight
Decimal odds are a chance upside down: divide 100 by the odds and you have the percentage the odds imply. Write that number as the weight:
- Odds of 2.20 → 100 ÷ 2.20 = 45 →
Home win|x45. - Odds of 3.60 → 100 ÷ 3.60 = 28 →
Draw|x28. - Odds of 3.70 → 100 ÷ 3.70 = 27 →
Away win|x27.
The three add up to 100 here because they were rounded to. Real odds add up to more than 100 – the difference is the bookmaker’s margin, and the wheel shows it as the slices being a little wider than the true chances.
What it is good for
- Seeing what a price actually means before you believe it.
- Teaching odds: the same three numbers as three slices explain themselves.
- Comparing two markets side by side – open the page twice.
- Settling a friendly prediction, with the wheel as the referee.
- Any question with known chances: an exam result, a weather forecast, a coin that is bent.
Counting the spins
Counter tallies the results against what the odds said. A hundred spins is the quickest way to see that 28 per cent is not “rare”, it is more than one in four:
It is a picture of probability, not a tip: the wheel knows nothing about the teams, and nothing it does here is betting.