What does decimal odds of 2.50 mean?

A $10 bet at 2.50 returns $25 total, $15 profit plus the original $10 stake. Decimal odds show the whole payout per dollar staked, not just the profit.

What does fractional odds of 5/1 mean?

A $1 bet profits $5, for a $6 total return. Fractional odds show profit relative to stake, read as "five-to-one."

How do you convert American odds to decimal odds?

For plus odds, divide by 100 and add 1 (+150 becomes 2.50). For minus odds, divide 100 by the absolute value and add 1 (-180 becomes about 1.56).

Fractional and Decimal Odds — OddsFoundry Learn

Quick answer

Decimal odds show your total payout per $1 staked (2.50 means a $10 bet returns $25). Fractional odds show profit relative to stake (5/1 means a $1 bet profits $5). Both describe the exact same price as American odds, just formatted differently.

Same price, three different labels

American odds (+150, -180) are the standard in the US. Step outside American sportsbooks, or onto a betting exchange, and the same price gets quoted as decimal odds or fractional odds instead. None of these formats change what the bet actually pays, they're just three different ways of writing the same number.

Decimal odds: the whole payout in one number

Decimal odds tell you your total return for every $1 staked, stake included. A decimal price of 2.50 means a $10 bet returns $25 total, your original $10 plus $15 profit. Decimal odds of exactly 2.00 is even money, anything above that is an underdog-style payout, anything below it is a favorite-style payout.

Reading decimal odds of 2.50

You stake	$10
You profit	$15
You get back	$25

Fractional odds: profit relative to stake

Fractional odds, the traditional UK format, show up as something like 5/1 (read "five-to-one") or 6/4. The fraction is profit divided by stake, not the total payout. 5/1 means a $1 bet profits $5, for a $6 total return. 6/4 means a $4 bet profits $6, for a $10 total return.

Reading fractional odds of 5/1

You stake	$1
You profit	$5
You get back	$6

Converting between the three

You don't need to memorize a formula, just the pattern. To go from American to decimal: plus odds divide by 100 and add 1 (+150 becomes 2.50), minus odds divide 100 by the number and add 1 (-180 becomes about 1.56). To get fractional from decimal, subtract 1 and reduce to a fraction (2.50 minus 1 is 1.50, or 3/2).

The same price, all three formats

American	+150
Decimal	2.50
Fractional	3/2

All three of these pay out identically. A $10 bet profits $15 no matter which format the book happens to display it in.

Why bother learning the other two

Most US sportsbooks default to American odds, so day-to-day you may never need this. But betting exchanges, offshore books, and a lot of the sharpest publicly available market data default to decimal, since it's easier to do math with (no plus/minus sign to track). Being able to read all three means a price is never confusing just because of how it's formatted.