Odds to Chance Calculator — Convert Moneyline Odds to Probability

What Is Implied Probability?

Implied probability is the mathematical conversion of betting odds into a percentage chance.
It tells you how likely the sportsbook believes an outcome is — and helps you compare that to your own estimation.

For example:

If odds are 2.00 (Decimal), the implied probability is 50% — meaning the bookmaker believes the event happens half of the time.

Use the Odds to Chance Calculator

Use our free Implied Probability Calculator below to instantly convert any odds format into true percentage chance:

The calculator automatically detects the format and shows:

• The implied probability (%)
• The fair odds (without vig, if available)
• The chance of winning vs. losing

How to Convert Odds to Probability (Formulas)

Depending on the odds format, the formula changes slightly. Let’s go through all three:

Decimal Odds → Probability

Example:
Odds 2.50 → 1/2.50=0.401 / 2.50 = 0.401/2.50=0.40 → 40% chance

Fractional Odds → Probability

Example:
Odds 5/2 → 2/(5+2)=0.28572 / (5 + 2) = 0.28572/(5+2)=0.2857 → 28.57% chance

Moneyline Odds → Probability

Moneyline odds can be positive or negative, and each uses a different formula.

So, when you convert Moneyline to probability, you get the sportsbook’s estimated chance.
If you’re curious about how to convert american odds manually or with a tool, our calculator handles this automatically.

Example: Comparing Odds and True Chance

Imagine two bets:

Together, those add up to 106.7% — more than 100%!
That extra margin is the bookmaker’s overround (their built-in profit).
With tools like ours, you can strip that margin to find “fair odds” and identify positive EV bets.

Why Implied Probability Matters

If you want to make smart betting decisions, you must compare:

• Bookmaker’s probability (from odds)
  vs.
• Your own estimated probability

This is the foundation of Value Betting (EV+).

Example:

• Book odds: 2.20 → implied probability = 45.45%
• Your estimate: 55% chance to win

That’s a value bet, because your probability > bookmaker’s.

Convert Moneyline to Probability — Step by Step

Let’s go deeper on Moneyline conversions, since that’s the most common format in U.S. markets.

Case 1: Positive Moneyline (+)

Used for underdogs.
Example: +200

Case 2: Negative Moneyline (–)

Used for favorites.
Example: -150

So, +200 = 33.3%, -150 = 60%, and you can use our Odds to Chance Calculator to verify these in one click.

How to Use Implied Probability in Betting Strategy

1. Find the implied probability using the calculator.
2. Estimate your own probability (based on stats, models, or intuition).
3. Compare both values.
4. • If your number is higher → positive expected value (EV+).
   • If lower → avoid the bet.

This process turns casual betting into data-driven decision-making — and it’s exactly what professional bettors use daily.

Bonus: Reverse Formula — Probability to Odds

Sometimes you want to go the other way — from chance to odds.

So if your model says the team has a 60% chance of winning:

• Decimal odds = 1.67
• Moneyline = -150

That means you should only bet if the line is better than -150 — otherwise, no edge.

Summary

Final Thoughts

So, when you need to convert odds into real chances, the Odds to Chance Calculator (also called an Implied Probability Calculator) is your best friend.
It demystifies bookmaker lines, helps identify +EV opportunities, and gives you full control over your betting decisions.

Remember: betting odds are just another way of expressing probability — and understanding that connection is what separates smart bettors from casual ones.