For anyone new to 20Bet sports betting or online casinos, understanding odds is the first crucial step. Odds are not simply figures but a probability, possible compensation, and risk/reward ratio. It could be that if you are betting on a football game, gambling on slots, or even attending a poker event, you need to learn how to read betting lines so as to make informed decisions.
This is a guide that covers the fundamentals so that even a total layman will be able to work with any betting platform with ease.
Why Odds Are the Foundation of Betting
Odds are the core of every wager. They provide three key pieces of information:
- The probability of an event happening.
- The potential payout if your bet wins.
- The value of one betting opportunity compared to another.
Understanding odds helps you avoid common mistakes like overestimating favorites, missing value on underdogs, or betting purely on instinct rather than analysis.
Main Odds Formats You’ll Encounter
Depending on where you bet, odds may appear in different formats. The three most common are decimal, fractional, and American (moneyline) odds.
Decimal Odds – The Simplest Format
- Example: 2.50
- How it works: Multiply your stake by the decimal number to see your total return.
- A $10 bet at 2.50 would return $25 total ($15 profit + $10 stake).
- Popular in Europe, Canada, and many online casinos because of their clarity.
Fractional Odds – Classic and Traditional.
- Examples: 3/1 (pronounced with three to one).
- Meaning: There is a 3-to-1 profit in every dollar that you gamble.
- A 3/1 bet of $10 would make you 30 in profit and have your 10 dollars back.
- It is still used in horse racing and in the traditional UK betting shops.
American Odds (Moneyline)
American odds are indicated as either positive or negative numbers:
- Positive ( +150): What is the amount of profit you would make on a 100-dollar bet?
You can make a bet of 100 dollars at +150 and get a 150-dollar profit plus your initial wages (250 in total).
- Negative (-150): The amount of money that you must bet in order to win one hundred.
Betting -150, a bet of $150 would make a profit of $100, and you add your stake ($250 in total).
Quick tip:
- When odds are positive, the odds normally represent an underdog.
- The favorite is normally represented by the negative odds.
The Relation between Odds and Probability.

Under every betting line, there is an implied probability. It is the estimate of the bookmaker on the probability of an outcome.
Basic formula of the odds of a decimal:
Probability%=1Decimal Odds1×100Probability%=Decimal Odds1100
Example:
- Decimal odds of 2.00 = 50% chance
- Decimal odds of 4.00 = 25% chance
The knowledge of this aids you in uncovering value bets, i.e., cases when you believe that the underlying probability is greater than the odds imply.
Common Mistakes Beginners Should Avoid
New bettors often make predictable errors. Here are the most frequent ones:
- Always betting on the favorite:
- Favorites don’t always win, and sometimes the payout isn’t worth the risk.
- Ignoring underdogs:
- Underdogs often have odds that offer better value, especially in unpredictable sports.
- Not accounting for the house edge:
- Bookmakers build a small margin into every line to ensure profit.
Building a Smart Betting Approach
Odds are more than just numbers — they can guide strategy. Here’s how to use them effectively:
- Compare different platforms: Odds vary, and even a small difference can affect profits over time.
- Track your bets: Keep a record to learn which markets and odds you handle best.
- Explore niche sports or games: Markets with less attention sometimes contain mispriced lines.
Final Thoughts
Knowledge of odds is the basis of winning the bet, regardless of whether one is betting on sports, slot machines, or casino games. Reading and interpreting odds correctly will help you to have power over your choices and not to guess randomly.
Begin with small bets, learn the life of betting lines, and concentrate on value instead of excitement. As time goes by, you will gain the self-assurance to work in any gambling set-up and make informed, rational decisions.