When you’re diving into the world of sports betting, particularly in South Africa (SA), understanding how to calculate true odds is crucial. True odds aren’t just some random numbers—they are the foundation of making informed, strategic bets that give you the best chance of winning. Whether you’re placing a bet on rugby, soccer, or cricket, getting to grips with true odds can help you assess value, spot opportunities, and avoid falling into common betting traps. In this guide, we’ll break down how to calculate true odds and apply this knowledge to your betting strategy.
What Are True Odds?
True odds are the foundation of understanding value in sports betting. They represent the real, unbiased probability of an event happening—without any manipulation by the sportsbook. Unlike the odds you see on most betting sites, which include a built-in margin to ensure the bookmaker makes a profit, true odds are purely mathematical. They are derived from raw statistical data and calculated probabilities, offering a fair and accurate reflection of how likely an outcome is to occur.
When we talk about true odds, we’re removing the so-called “juice” or “vig” (short for vigorish), which is the bookmaker’s cut. This margin is why even bets that seem fair might not offer long-term value. True odds strip all of that away, giving us the clean probability. It’s like looking behind the curtain and seeing the real numbers that drive betting decisions. If you’re serious about making smart bets, understanding and using true odds is a must.
To calculate true odds, bettors analyze various factors such as team performance, historical data, player statistics, and even situational variables like weather or home advantage. By weighing these elements, you can estimate how likely a particular outcome is. This estimation is then converted into odds, allowing you to compare them with what the bookmaker is offering. If your calculated true odds are better than the market odds, you’ve found a value bet.
Let’s say you’re betting on a soccer match where both teams are evenly matched. Logically, there’s a 50% chance for each team to win. That means the true odds should be 2.00 in decimal form or 1/1 in fractional terms. If the bookmaker offers odds lower than that, they’re baking in their profit. If you can consistently spot discrepancies between true odds and offered odds, you’re on the path to long-term profitability.
Why Do True Odds Matter in Sports Betting?
- They help you identify real value in the market.
Bookmakers build their profit into the odds they offer. This is called the “vig” or “juice.” By understanding true odds, you can strip away that margin and reveal whether a bet is truly worth making. You’re not just accepting what the bookie gives you—you’re evaluating it with a sharper lens. - They allow you to calculate whether a bet is +EV (positive expected value).
In the long run, betting only makes sense if your bets have a positive expected value. That means the return you expect to make exceeds the risk you’re taking. True odds give you the framework to determine if the potential reward outweighs the risk based on real probabilities. - They prevent emotional or biased betting.
It’s easy to bet based on gut feelings, team loyalty, or hype. But true odds bring you back to reality. They keep your betting grounded in logic and statistics, helping you avoid emotional decisions that often lead to losses. - They empower you to bet like a professional.
Casual bettors often rely on instinct or bookmaker suggestions. Sharp bettors, on the other hand, rely on numbers—and true odds are at the heart of those numbers. If you’re serious about betting and not just throwing money for fun, this is the skill that separates pros from the crowd. - They expose overpriced or underpriced lines.
Once you know how to calculate true odds, you’ll start seeing mismatches in the market. If a sportsbook is offering lower odds than the true probability suggests, you avoid it. If the odds are higher than they should be, that’s a green light—it’s a value bet. - They help manage risk effectively.
Betting is all about risk versus reward. True odds let you calculate how risky a bet really is, helping you avoid reckless bets and focus on those that make sense from a mathematical perspective. - They help you develop long-term profitability.
Betting isn’t about winning every bet—it’s about winning enough value bets to come out ahead in the long run. Understanding true odds helps you stay consistent, disciplined, and focused on the big picture, not just one-off wins or losses. - They make you independent from tipsters or paid advice.
Once you master the art of finding true odds, you won’t have to rely on betting “experts” or paid tip services. You’ll be able to analyze games yourself and trust your own numbers. - They improve your overall understanding of the sport.
Calculating true odds forces you to dig deeper into statistics, form, injuries, and even advanced metrics. This leads to a more refined and nuanced understanding of the sport itself, which feeds back into better betting decisions.
The Basics of Calculating True Odds
| Odds Format | Example Odds | Implied Probability (%) | How to Read It | What You Win on R100 Bet |
| Decimal Odds | 2.50 | 40.00% | You’ll get R2.50 for every R1 staked (includes your original stake). | R250 total (R150 profit) |
| Fractional Odds | 3/2 | 40.00% | For every R2 you bet, you profit R3. Your total return includes your stake. | R250 total (R150 profit) |
| American Odds | +150 | 40.00% | A +150 line means you win R150 for every R100 staked. | R250 total (R150 profit) |
| American Odds | -250 | 71.43% | A -250 line means you must bet R250 to win R100 in profit. | R350 total (R100 profit) |
| True Odds | 2.50 / 3/2 / +150 | 40.00% | These are the fair odds reflecting the real chance of winning without bookmaker vig. | Same as calculated above |
Formula for Calculating True Odds
To calculate true odds, you need to start with the probability of an event occurring. The formula for true odds is straightforward: True Odds = 1 / Probability of Event
This formula helps you translate the likelihood of an outcome into its corresponding odds. For instance, if the probability of an event happening is 0.50 (or 50%), the true odds are 1 / 0.50, which equals 2.00 in decimal odds. In fractional terms, this would be expressed as 1/1. Essentially, you’re determining how much you stand to win relative to your stake based on the probability of that outcome happening.
The calculation is simple, but it requires accurate probability data. When you’re calculating true odds for a specific sports event, you need to use the most relevant statistical information—such as team form, head-to-head records, and other factors—to come up with the event’s probability. This probability reflects the actual likelihood of the outcome, free from any bookmaker margin or juice.
Once you have your probability, the formula works to convert that into true odds. By understanding true odds, you can compare the bookmaker’s odds with your own and assess whether a bet offers value. If the bookmaker’s odds are higher than your calculated true odds, you may have found a potential value bet. Conversely, if the bookmaker’s odds are lower, then you can pass on the bet, knowing it doesn’t provide good value. This mathematical approach is vital for long-term success in sports betting.
Step-by-Step Guide to Calculate True Odds
- Determine the probability of the outcome:
Start by estimating the likelihood of the event occurring. This could involve statistical analysis, reviewing historical data, head-to-head matchups, or considering current player conditions. For example, after evaluating all the data, you conclude that a soccer team has a 60% chance of winning. - Apply the formula:
Use the true odds formula to calculate the actual odds based on the probability of the event.
The formula is:
True Odds = 1 / Probability of Event
For a 60% chance (0.60), the calculation would be:
True Odds = 1 / 0.60 = 1.67
This means the true odds for the soccer team to win are 67 in decimal odds. - Convert the true odds into the desired format:
If you prefer fractional odds over decimal, you can convert the decimal odds into fractional form.
The conversion is simple:
Fractional Odds = Decimal Odds – 1
So for 67 decimal odds, you subtract 1:
1.67 – 1 = 0.67, which equals 2/3 in fractional odds. - Final Odds Interpretation:
After conversion, you have two possible ways of expressing the true odds:- In decimal odds, it is 67.
- In fractional odds, it is 2/3.
These odds represent the probability of the soccer team winning, with 1.67 being the payout for every unit wagered.
Applying True Odds to South African Sports Bets
| Sport | Step | Example/Calculation | True Odds Formula | Outcome/Analysis |
| Soccer (PSL) | Research the teams | Analyze recent form, head-to-head statistics, injuries, etc. | ||
| Estimate the probabilities | Estimate Team A has a 55% chance of winning. | |||
| Calculate true odds | True Odds = 1 / 0.55 = 1.82 | 1.82 Decimal Odds | 9/11 in Fractional Odds | |
| Compare with bookmaker odds | Bookmaker offers odds of 2.00 for Team A to win. | This may indicate value in the bet | ||
| Rugby (Springboks) | Gather data | Look at team performance, player quality, and previous match outcomes. | ||
| Estimate the probabilities | Estimate a 70% chance for a team to win. | |||
| Calculate true odds | True Odds = 1 / 0.70 = 1.43 | 1.43 Decimal Odds | 3/7 in Fractional Odds | |
| Analyze bookmaker odds | Bookmaker offers odds of 1.80 for the same team. | The bookmaker’s odds may be overvalued | ||
| Cricket (ICC WC) | Consider all factors | Consider weather, pitch, player form, and team composition. | ||
| Estimate the probabilities | Estimate Team A has a 65% chance of winning. | |||
| Calculate true odds | True Odds = 1 / 0.65 = 1.54 | 1.54 Decimal Odds | ||
| Compare with bookmakers | Bookmaker offers odds of 1.60 for Team A to win. | The bookmaker’s odds slightly exceed true odds, indicating potential value |
How Bookmakers Adjust Odds
Bookmakers typically apply a margin, often referred to as “juice” or “vig,” to the odds they offer in order to guarantee a profit. This margin is added to the true odds to ensure that the bookmaker has an edge over the bettor. The margin varies depending on the sport, event, and the bookmaker’s business model. It ensures that, regardless of the outcome of the bet, the bookmaker remains profitable in the long run.
To calculate the odds that reflect the bookmaker’s margin, you can use a simple formula. The true odds, which are based on the actual probability of an event occurring, are divided by a factor that accounts for the bookmaker’s margin. This adjusted figure provides the odds that the bookmaker offers to the bettors. It’s important to understand this adjustment because it represents the odds you’re actually betting on, as opposed to the true odds that reflect the unbiased likelihood of an event happening.
For example, if the true odds for a bet are 2.00 and the bookmaker’s margin is 5%, you can adjust the true odds by dividing them by 1 minus the margin. In this case, the formula would look like this: Adjusted Odds = 2.00 / (1 – 0.05) = 2.00 / 0.95 = 2.11. This means the odds you’re betting on are slightly higher than the true odds, reflecting the bookmaker’s margin.
Understanding how bookmakers adjust odds is critical for bettors because it helps them evaluate the value of the odds being offered. By factoring in the bookmaker’s margin, you can better compare the adjusted odds to the true odds and decide if the bet is worth making. This knowledge helps bettors avoid overestimating the value of a bet and ensures more informed decisions when placing bets.
Common Mistakes to Avoid
- Ignoring bookmaker margins: Always account for the bookmaker’s margin when calculating true odds. Failing to adjust for the bookmaker’s edge can lead to inaccurate assessments of the true value of a bet.
- Overestimating probabilities: Make sure your probabilities are realistic and based on solid data. Overestimating your favorite team’s chances of winning can lead to poor betting decisions and unnecessary losses.
- Betting without data: Never place bets without thorough research. Relying on gut feelings or emotions rather than analyzing the statistics, form, and other relevant factors can result in poor outcomes. Proper research and analysis are essential for making informed decisions.
- Failing to adjust for market changes: The odds can fluctuate as new information becomes available. If you don’t adjust for these changes, you may miss out on better value bets or fail to spot when the market has overreacted to certain information.
- Not diversifying your bets: Placing all your bets on a single outcome or team can expose you to high levels of risk. Diversifying your bets across different events or markets helps spread the risk and increases your chances of long-term success.
- Underestimating variance: Even the best research and strategies won’t guarantee a win every time. Sports betting involves variance, so don’t be discouraged by short-term losses. Focus on maintaining a consistent approach over the long term.
- Chasing losses: Trying to recover from losses by making higher-risk bets can lead to even greater losses. Stick to your strategy, and avoid making impulsive decisions when things aren’t going your way.