Why odds formats matter on crypto sportsbooks
Crypto sportsbooks usually let you show odds as decimal, fractional, or American (moneyline). The format changes how prices look—not the underlying chance or payout logic—so being fluent in all three makes it easier to line-shop and compare offers across sites. Many sportsbooks and exchanges explain that the probability is the same regardless of format and provide converters or toggles in settings.
The three formats at a glance
Decimal odds
Show total return per 1 unit staked (stake included). For example, 1.91 returns 1.91 per 1 staked. They’re popular because you can compute returns by multiplying stake × odds.
Fractional odds
Show profit relative to stake (e.g., 5/2 means profit of 5 for every 2 staked; total return = stake + profit). Common in the UK and Ireland.
American (moneyline) odds
Positive numbers (e.g., +150) show profit on a 100-unit stake; negative numbers (e.g., −120) show how much you must stake to profit 100.
Converting odds to implied probability
Use these quick formulas to see what the odds imply about the chance of winning.
Decimal → probability
p = 1 / d. Example: 1/1.91 ≈ 52.36%.
Fractional → probability
p = 1 / (f + 1), where f is the fraction (e.g., 5/2 → 1 / (2.5 + 1) = 28.57%).
American → probability
For positive odds +A: p = 100 / (A + 100). For negative odds −A: p = A / (A + 100). Example: +150 → 100/250 = 40%; −120 → 120/220 ≈ 54.55%.
Many introductory guides and calculators present the same conversions—use any reputable converter to double-check your math.
What the margin (overround, vig) means
When you add up implied probabilities for all mutually exclusive outcomes in a market, the total usually exceeds 100%. That extra percentage is the bookmaker’s margin (also called the overround or “vig/juice”). For example, a typical two-way point-spread price of −110 on both sides implies about 52.38% per side, totaling ~104.76%—the ~4.76% above 100% is the margin. Understanding the margin helps explain why raw odds are slightly worse than “fair” odds.
Removing the margin to compare “fair” prices
To de-vig a market quickly, divide each implied probability by the market total, then renormalize to 100%. Example 3-way soccer market:
• Decimal odds: Home 2.40, Draw 3.20, Away 3.10
• Implied probabilities: 41.67%, 31.25%, 32.26% → total ≈ 105.17%
• De-vig “fair” probs (normalized): ~39.62%, 29.71%, 30.67%
• Fair odds after de-vig: ~2.52, 3.37, 3.26
This simple normalization mirrors methods discussed by betting resources and shows how margin is spread across outcomes.
Reading moneylines: 2-way vs 3-way (soccer gotchas)
Two-way moneylines (common in U.S. sports) list only two outcomes and usually include overtime. Three-way soccer moneylines list Home/Draw/Away and settle after regulation time (90 minutes plus referee-added stoppage); extra time or penalties are not included unless specified. Always check the house rules for how settlement works.
Worked micro-examples
Example A: Convert −120 to implied probability
p = 120 / (120 + 100) = 54.55%. If your own model says the team wins 56%, the edge is small but positive.
Example B: Convert +200 to decimal and probability
Decimal = 1 + (200/100) = 3.00; probability = 100 / (200 + 100) = 33.33%.
Example C: Fractional 5/2 to decimal and probability
Decimal = 1 + 5/2 = 3.50; probability = 1 / 3.50 = 28.57%.
Crypto-site specifics (what’s different, what isn’t)
Odds formats and settlement rules work the same whether you fund with fiat or crypto; the difference is payments. Most books let you toggle display format in settings, and many settle payouts internally using decimal math even if you view American or fractional prices.
Quick glossary
Moneyline (American)
Positive = underdog payout on 100-unit stake; negative = stake needed to profit 100.
Decimal odds
Total return including stake per 1 unit staked; multiply stake × odds.
Fractional odds
Profit relative to stake (e.g., 7/2). Total return = stake + profit.
Overround / vig
The bookmaker’s margin reflected by implied probabilities summing above 100%.
Responsible gambling and KYC notes
Licensed operators generally must verify your name, address, and date of birth before allowing you to gamble online. If you need help, the National Problem Gambling Helpline is available at 1-800-GAMBLER for confidential support and referrals.
FAQs
Do different odds formats change my payout?
No. Formats are just different ways to display the same price and probability; total returns are equivalent when converted correctly.
What’s the easiest format for quick math?
Decimal is often easiest because return = stake × odds and includes your stake in the total.
How do I know if soccer markets include extra time?
Read the rules. Standard 3-way soccer markets settle after 90 minutes plus stoppage; extra time and penalties are separate markets unless clearly stated.
Where can I convert odds fast?
Use reputable converters and calculators that show decimal, fractional, American, and implied probability side-by-side.
