In this guide
Key takeaways
- Decimal odds show your total return per 1 staked, fractional odds show profit per 1 staked, and American odds show profit on 100 (plus) or the stake needed to win 100 (minus).
- Every format converts through decimal: decimal = fractional + 1; for plus American, decimal = American ÷ 100 + 1; for minus American, decimal = 100 ÷ |American| + 1.
- Implied probability = 1 ÷ decimal odds. It tells you how often a bet must win just to break even at that price.
- Add up the implied probabilities across all outcomes of a market and you get more than 100%. The excess is the bookmaker's margin, and it is why bettors as a group lose over time.
- Removing the margin gives you a rough "fair" price. It's a reading tool, not a prediction, and it never turns a bet into a sure thing.
Most sportsbooks in Colombia, Peru, Chile and much of Latin America show decimal odds by default. US sites use American odds, and British bookmakers still use fractions. We already have a quick overview of the three formats. This guide goes further: it gives you a conversion method you can do in your head, a full reference table, worked examples in pesos and dollars, and the arithmetic that shows how much margin is baked into a price. None of this will help you win more often. It will help you understand exactly what you're paying for.
Betting is for adults of legal age in their country (18+ in Colombia). It is entertainment with a cost, not a way to make money. If betting stops being fun, see our responsible gambling tools and help guide.
What each odds format is really telling you
All three formats describe the same thing: how much the sportsbook pays if your selection wins. They differ only in what they count.
Total return per 1 staked
Multiply your stake by the odds. COP 10,000 at 2.50 returns COP 25,000, including your original 10,000. Profit is 15,000.
Profit per unit staked
3/2 means you win 3 for every 2 staked, on top of getting your stake back. It's the same price as 2.50 decimal.
Profit on 100, or stake to win 100
+150 means a 100 stake wins 150 profit. −150 means you must stake 150 to win 100 profit.
The one detail that trips up beginners: decimal odds include your stake, the other two formats don't. That's why the decimal number is always exactly 1 higher than the equivalent fraction (2.50 versus 1.50, written as 3/2).
A bet that pays the same profit as your stake is 2.00 in decimal, 1/1 (or "evens") in fractional, and +100 in American. Anything shorter than that means you risk more than you can win.
The conversion formulas, step by step
The simplest approach is to treat decimal as the hub. Convert whatever you have into decimal, then out to the format you want.
Into decimal
- From fractional: divide the top by the bottom, then add 1. 5/2 → 2.5 + 1 = 3.50.
- From positive American: divide by 100, then add 1. +240 → 2.40 + 1 = 3.40.
- From negative American: divide 100 by the number (ignore the minus sign), then add 1. −125 → 100 ÷ 125 = 0.80, + 1 = 1.80.
Out of decimal
- To fractional: subtract 1 and write the result as a fraction. 1.80 → 0.80 → 4/5.
- To American, when decimal is 2.00 or higher: (decimal − 1) × 100, shown with a plus. 3.40 → +240.
- To American, when decimal is below 2.00: −100 ÷ (decimal − 1). 1.80 → −100 ÷ 0.80 = −125.
For plus American odds, just move the decimal point two places and add 1: +350 is 4.50. For minus odds, remember a few anchors: −200 is 1.50, −150 is 1.67, −110 is about 1.91, and −100/+100 is 2.00.
Odds conversion reference table
Values are rounded. Implied probability is 1 ÷ decimal, shown as a percentage, and doesn't account for the margin (more on that below).
| Fractional | Decimal | American | Implied probability |
|---|---|---|---|
| 1/10 | 1.10 | −1000 | 90.9% |
| 1/5 | 1.20 | −500 | 83.3% |
| 1/4 | 1.25 | −400 | 80.0% |
| 1/3 | 1.33 | −300 | 75.0% |
| 1/2 | 1.50 | −200 | 66.7% |
| 4/6 | 1.67 | −150 | 60.0% |
| 4/5 | 1.80 | −125 | 55.6% |
| 10/11 | 1.91 | −110 | 52.4% |
| 1/1 (evens) | 2.00 | +100 | 50.0% |
| 11/10 | 2.10 | +110 | 47.6% |
| 6/4 | 2.50 | +150 | 40.0% |
| 7/4 | 2.75 | +175 | 36.4% |
| 2/1 | 3.00 | +200 | 33.3% |
| 5/2 | 3.50 | +250 | 28.6% |
| 3/1 | 4.00 | +300 | 25.0% |
| 4/1 | 5.00 | +400 | 20.0% |
| 5/1 | 6.00 | +500 | 16.7% |
| 7/1 | 8.00 | +700 | 12.5% |
| 10/1 | 11.00 | +1000 | 9.1% |
Worked examples you can check yourself
Example 1: A decimal price in pesos
You see a home win at 2.10 and stake COP 20,000.
- Total return if it wins: 20,000 × 2.10 = COP 42,000.
- Profit: 42,000 − 20,000 = COP 22,000.
- Same price in other formats: 11/10 fractional, +110 American.
- Implied probability: 1 ÷ 2.10 = 47.6%.
Example 2: A negative American line
A US-facing site lists a team at −160 and you want to stake USD 40.
- Decimal: 100 ÷ 160 = 0.625, + 1 = 1.625 (often shown as 1.63).
- Profit: 40 × 0.625 = USD 25. Total return: USD 65.
- Implied probability: 1 ÷ 1.625 = 61.5%.
Example 3: A fractional price on a UK site
A British bookmaker quotes 9/4.
- Decimal: 9 ÷ 4 = 2.25, + 1 = 3.25.
- American: (3.25 − 1) × 100 = +225.
- Implied probability: 1 ÷ 3.25 = 30.8%.
Example 4: Combining selections
In a combination bet (a parlay or combinada), decimal odds multiply. Two selections at 1.80 and 2.10 give 1.80 × 2.10 = 3.78. A COP 10,000 stake would return COP 37,800 if both win. The margin multiplies too, which is one reason combination bets are usually worse value than they look.
Implied probability and the bookmaker's margin
Implied probability is simply the break-even point. At 2.10, your bet has to win 47.6% of the time for you to come out even over the long run. If you think the true chance is lower, the price is poor for you.
Here is the important part. Take a full market, such as the three outcomes of a football match, and add up the implied probabilities. In a fair world they would total exactly 100%. At a real sportsbook, they total more. That excess is called the overround or margin, and it's how the house gets paid.
Worked margin example (illustrative prices)
| Outcome | Decimal odds | Implied probability | "Fair" share after removing margin | "Fair" odds |
|---|---|---|---|---|
| Home | 2.10 | 47.62% | 45.05% | 2.22 |
| Draw | 3.30 | 30.30% | 28.67% | 3.49 |
| Away | 3.60 | 27.78% | 26.28% | 3.81 |
| Total | — | 105.70% | 100.00% | — |
These prices are made up for the arithmetic; they aren't from any real match. The book adds up to 105.70%, so the overround is 5.70 percentage points. To get the "fair" share, divide each implied probability by the total (for example, 47.62 ÷ 105.70 = 45.05%). Then flip it back into odds (1 ÷ 0.4505 = 2.22).
What does that mean for your money? If someone spread stakes across all three outcomes in proportion to their implied probabilities, they would get back about 1 ÷ 1.057 ≈ 94.6% of what they staked, whatever the result. The missing 5.4% is the house's share. This is a simplified model; real sportsbooks may load more margin onto some outcomes than others. The direction is always the same, though: the prices are tilted in the house's favor.
Because of the margin, the average bettor loses money over time. That isn't bad luck, it's how the prices are built. Treat betting as paid entertainment and set a budget you are comfortable losing. Our bankroll management guide shows how.
Two-way markets
The same check works for over/under or yes/no markets. If both sides of an over/under line are priced at 1.90, each side implies 52.6%, for a total of 105.3%. A two-way market priced at 2.00 on both sides would have no margin, and you'll rarely see one.
Practical habits for reading odds
- Pick one display format and stick with it. Most sportsbooks let you switch format in account settings. Decimal is easiest for multiplying stakes.
- Always think in implied probability. Ask "do I believe this happens more than X% of the time?" rather than "is this a big number?"
- Compare the margin between licensed sites. Add up a market's implied probabilities on two authorized operators. The lower total means you are paying less for the same bet.
- Be suspicious of long-odds combinations. The payout is eye-catching, but the margin compounds with every leg you add.
- Don't confuse a price with a prediction. Odds reflect the sportsbook's pricing and the money it has taken, not a guarantee of anything.
Before you bet anywhere in Colombia, make sure the site is on the official list. Our Coljuegos guide walks through the check.
Frequently asked questions
Which odds format do Latin American sportsbooks use?
Most sportsbooks serving Colombia and much of Latin America show decimal odds by default, and many let you switch to American or fractional in your account settings.
How do I convert American odds to decimal?
For positive American odds, divide by 100 and add 1, so +150 becomes 2.50. For negative odds, divide 100 by the number without the minus sign and add 1, so -150 becomes about 1.67.
What is implied probability?
Implied probability is 1 divided by the decimal odds. It is the percentage of the time a bet must win to break even at that price. Odds of 2.50 imply 40 percent.
Why do the implied probabilities add up to more than 100 percent?
The extra amount is the bookmaker's margin, also called the overround. It means the prices pay slightly less than fair odds, which is how the sportsbook makes money over time.
Does understanding odds help me win more often?
No. Understanding odds helps you see the price and the margin you are paying. It does not change outcomes, and no method guarantees a profit. Bet only what you can afford to lose.
Learn the basics before you bet
Browse our guides to Latin American sportsbooks, payments and betting markets, written to help you understand what you are betting on.
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18+ only. This article is general information for adults and is not legal, financial or tax advice. Betting involves real risk of loss; never bet money you cannot afford to lose, and no bet, system or tip can guarantee a win. Rules and listings change, so confirm details with the official sources linked above. This article contains no affiliate links. If gambling is causing you harm, stop and reach out for support.