How to Read Betting Odds (Decimal, American & Fractional)

The 30-second answer

Betting odds tell you two things at once: how much you win if the bet lands and how likely the sportsbook thinks it is. The same price can be written three ways — decimal (1.91), American (-110) or fractional (10/11) — and they all mean exactly the same thing.

Decimal odds

Decimal odds are the total return per 1 unit staked, including your stake.

• 1.50 — stake 100, get back 150 (profit 50).
• 2.00 — stake 100, get back 200 (profit 100). This is "even money".
• 3.40 — stake 100, get back 340 (profit 240).

Profit = stake × (odds − 1). Decimal is the default on Saint Picks because parlay math is a simple multiplication and there are no negative numbers to trip over.

American odds

American odds use a plus or minus sign around a base of 100.

• Negative (-150): how much you must risk to win 100. Risk 150 → profit 100. Favorites are negative.
• Positive (+140): how much you win on a 100 risk. Risk 100 → profit 140. Underdogs are positive.

To convert: for negative odds, decimal = 1 + 100 / |odds| (so -150 = 1.67). For positive odds, decimal = 1 + odds / 100 (so +140 = 2.40).

Fractional odds

Common in the UK and horse racing. 5/2 means profit 5 for every 2 staked — decimal 3.50. 1/2 means profit 1 for every 2 staked — decimal 1.50. Decimal = 1 + numerator / denominator.

Quick conversion table

• 1.25 = -400 = 1/4 (80% implied)
• 1.50 = -200 = 1/2 (66.7%)
• 1.67 = -150 = 4/6 (60%)
• 1.91 = -110 = 10/11 (52.4%)
• 2.00 = +100 = 1/1 (50%)
• 2.50 = +150 = 6/4 (40%)
• 3.00 = +200 = 2/1 (33.3%)
• 5.00 = +400 = 4/1 (20%)

Implied probability — the number that matters

Divide 1 by the decimal odds. 1.91 → 52.4%. That's the win rate you need just to break even. If you believe the true chance is higher than the implied probability, the bet has value; if not, it doesn't — however "likely" it feels. We cover this in depth in the implied probability and expected value guide.

Why -110 on both sides doesn't add to 100%

A standard spread is -110 / -110. Each side implies 52.4%, which sums to 104.8%. The extra 4.8% is the vig (juice) — the sportsbook's margin. Every Saint Picks selection is compared to a vig-free fair price, and we only publish when the book's number is clearly worse than our projection.

Change your odds format on Saint Picks

Signed-in members can switch between decimal, American and fractional in the Bankroll settings. Picks, parlays and your logged bets all follow the format you choose.