Professional Odds Calculator & Converter

Betting odds represent the probability of an event occurring and determine how much you can win from a bet. They show the ratio between the amount wagered and the potential payout. Higher odds indicate lower probability events with larger potential payouts, while lower odds suggest more likely outcomes with smaller returns.

Example: If a team has odds of 2.50 (decimal), there's approximately a 40% chance they'll win, and a $100 bet would return $250 total ($150 profit + $100 stake).

Decimal odds show your total return for every $1 wagered, including your original stake. They're the most straightforward format for calculating payouts.

How to calculate: Total Return = Bet Amount × Decimal Odds

Examples: 1.50 = $150 return on $100 (66.67% probability) | 3.00 = $300 return on $100 (33.33% probability)

Fractional odds show the ratio of profit to stake. Format: Profit/Stake. Popular in UK and Ireland.

Examples: 3/1 = Win $3 for every $1 bet | 5/2 = Win $5 for every $2 bet | 1/4 = Win $1 for every $4 bet (favorites)

Moneyline odds use + and - symbols based on $100 bets.

Positive (+): Profit on $100 bet. +200 = Win $200 on $100 bet (underdog)

Negative (-): Amount to bet to win $100. -200 = Bet $200 to win $100 (favorite)

Implied probability converts odds to percentage showing bookmaker's assessment of likelihood. Essential for finding value bets.

Formula: (1 ÷ Decimal Odds) × 100

Use case: If you think a team has 60% chance but odds show 50%, that's a value bet.

Decimal to Fractional: (Decimal - 1) = Fractional. Example: 2.50 = 3/2

Decimal to Moneyline: If ≥2.00: (Decimal-1)×100. If <2.00: -100/(Decimal-1)

Use our calculator: Simply enter any format and get instant conversions!

Decimal: Profit = (Stake × Decimal Odds) - Stake

Fractional: Profit = Stake × (Numerator ÷ Denominator)

Moneyline: Positive: Profit = Stake × (Odds ÷ 100). Negative: Profit = Stake ÷ (|Odds| ÷ 100)

Profit: Your winnings only (what you gain)

Total Return: Profit + your original stake (total amount returned)

Example: $100 bet at 2.50 odds = $150 profit + $100 stake = $250 total return

The margin is the bookmaker's built-in profit. When you add up implied probabilities of all outcomes, they exceed 100%.

Example: Team A: 1.90 (52.6%) + Team B: 1.90 (52.6%) = 105.2% total (5.2% margin)

Lower margins = better value for bettors

Value exists when your assessed probability exceeds the implied probability from odds.

Example: You think Team A has 60% chance to win, but odds of 2.00 imply only 50% chance = Value bet

Formula: Value = (Your Probability × Decimal Odds) - 1. Positive = value.

Parlays combine multiple bets. All selections must win. Odds multiply together for massive payouts but exponentially lower probability.

Calculation: Multiply all decimal odds. Example: 1.80 × 2.00 × 1.50 = 5.40 parlay odds

Use our parlay calculator for complex combinations!

Decimal: Easiest for calculations and comparisons. Used globally.

Fractional: Traditional UK format. Good for understanding profit ratios.

Moneyline: Standard in US. Clear favorite/underdog distinction.

Odds are surprisingly accurate probability indicators, especially in liquid markets. Studies show they predict outcomes better than most expert opinions.

However: They include bookmaker margin and public bias, so true probability is slightly different from implied probability.

Odds move based on: betting volume, new information (injuries, weather), expert opinions, and balancing bookmaker risk.

Heavy betting on one side = odds shorten (lower). Bookmakers adjust to encourage betting on the other side.

1. Confusing profit with total return

2. Forgetting to include stake in total return calculations

3. Mixing up positive/negative moneyline formulas

4. Not accounting for bookmaker margin when assessing value

1. Enter odds in any format - others auto-calculate

2. Add your bet amount to see exact profit and return

3. Check implied probability to assess value

4. Use alongside our parlay and arbitrage calculators for advanced strategies

1. Understand implied probability and find value bets

2. Use proper bankroll management (1-5% per bet)

3. Track all bets and calculate ROI

4. Shop for best odds across multiple bookmakers

5. Focus on sports/markets you understand deeply

Professionals use odds to: identify market inefficiencies, calculate expected value, determine optimal bet sizing (Kelly Criterion), find arbitrage opportunities, and model their own probabilities.

Key insight: They treat betting as data-driven investing, not gambling. Math and discipline beat intuition.