Sun, 05 Jul 2026

How betting odds work: decimal odds explained

What a decimal price like 2.10 actually means, how to read implied probability, and why the same match is priced differently at every bookmaker.

Every South African bookmaker prices its markets in decimal odds. A price of 2.10 next to Kaizer Chiefs isn’t a rating or a tip. It’s a multiplier: stake × price = total return if that outcome happens.

Reading a decimal price

Bet R100 at 2.10 and a win returns R210: your R100 back plus R110 profit. Bet R100 at 1.50 and a win returns R150. The higher the number, the less likely the betting site rates that outcome, and the more it pays if it comes in. Nothing about the price says what will happen. It only says what you get paid if it does.

From price to probability

Flip the price over and you get the market’s implied probability: 1 ÷ price. A price of 2.10 implies 1 ÷ 2.10 = 47.6%. A price of 1.50 implies 66.7%. Our odds converter does this instantly for decimal, fractional and American formats if you’d rather not do the division by hand.

Implied probability isn’t the bookmaker’s private forecast of who wins. It’s what the price says, once you strip out the built-in cost of betting with them. Which brings up the next question.

Why the numbers don’t add up to 100%

Take a three-way match: home, draw, away. Convert all three prices to implied probability and add them up. On almost every betting site, the total comes out above 100%. Not because the betting site thinks all three outcomes combined are more likely than certain. It’s because that excess is the bookmaker’s margin, sometimes called the overround, built into every price on the market.

A market priced at exactly 100% would be fair: no house edge, no cost to you beyond the risk of losing your stake. Markets never actually price at 100%. The gap between the total and 100% is what betting with that site costs you over time, regardless of which side you back. We measure that gap for every licensed SA betting site and publish it on our best-value page; the full method is on the methodology page, and what that gap actually costs you is broken down in how we measure bookmaker margins.

Why the same match gets different prices

Two betting sites covering the same Chiefs fixture rarely quote the same number. Each sets its own margin, weighs its own liability, and reacts to its own customers’ bets at its own speed. One might move a price within minutes of a team news update; another leaves it untouched for hours. None of that is wrong. It’s just two separate businesses pricing the same event independently.

The practical consequence: the best price for any single outcome is rarely at the same betting site two matches running. Checking one site and betting there means accepting whatever number that one site happened to land on.

What OddsBash does with this

We collect prices from every licensed South African betting site we track, several times a day and more often close to kick-off, and show the best available number for each outcome side by side. Every price carries the time we collected it, so you’re never looking at a number that’s quietly gone stale. Compare a match on our odds pages and the highlighted price is simply the best one live across the sites we measure, not a recommendation on which side to take.