Fractional Odds

Fractional odds are the traditional UK odds format, still common on horse racing and some legacy platforms. They express the profit you’d make relative to the amount staked.

How They Work

A fractional price reads as “profit/stake.”

• 5/1 = $5 profit for every $1 staked (a $1 bet returns $6 total). Equivalent to +500 American.
• 2/1 = $2 profit per $1 staked. Equivalent to +200 American or 3.00 decimal.
• 1/1 = $1 profit per $1 staked. Even money. Equivalent to +100 American or 2.00 decimal.
• 1/2 = $1 profit per $2 staked. Equivalent to -200 American or 1.50 decimal.
• 5/2 = $5 profit per $2 staked. Equivalent to +250 American or 3.50 decimal.

A fractional price of “X to Y” can also be read as “X to Y odds against” — with 5/1, you’re getting 5-to-1 odds.

Why It Matters

For US bettors, fractional odds are mostly something to recognize, not something to use day-to-day. They’re falling out of favor even in the UK, where decimal odds are increasingly standard. The main place you’ll still encounter them is horse racing, where fractional pricing remains tradition.

Converting fractional to decimal: divide the numerator by the denominator and add 1. So 5/2 → (5÷2) + 1 = 3.50.

Implied probability of fractional odds: denominator ÷ (numerator + denominator). So 5/1 → 1 ÷ 6 = 16.7%.

For more on reading and converting between odds formats, see How Betting Odds Work.