Odds Calculator
Convert between American, decimal, fractional, and implied probability instantly. Enter any one format and the rest update live. Includes a payout preview based on your stake.
How to read American odds
Negative odds (e.g., -150) show how much you must risk to win $100. -150 means risk $150 to win $100. Negative odds always indicate the favorite.
Positive odds (e.g., +200) show how much you win on a $100 risk. +200 means risk $100 to win $200. Positive odds always indicate the underdog.
The standard "juiced" line at US sportsbooks is -110 / -110 (decimal 1.91 each side). The 4.55% house edge per side is built into this pricing — see our hold calculator to quantify the vig on any market.
Converting odds in your head
Negative → decimal: divide 100 by the absolute value, add 1. -200 → (100/200) + 1 = 1.50.
Positive → decimal: divide by 100, add 1. +250 → (250/100) + 1 = 3.50.
Decimal → implied: 1 / decimal. 1.50 → 1/1.50 = 66.7%.
Odds Calculator FAQ
How do I convert -150 American odds to decimal?
-150 American odds equal 1.667 in decimal format. The formula for negative American odds is decimal = (100 / |odds|) + 1.
How do I convert +200 American odds to implied probability?
+200 American odds imply a 33.33% probability. The formula for positive odds is probability = 100 / (odds + 100).
What is decimal odds 1.91 in American format?
Decimal odds 1.91 equal approximately -110 American. The standard "juiced" line at most US sportsbooks.
Why do my numbers round differently on different sportsbooks?
Sportsbooks round differently — some to two decimals, others to the nearest 5 cents. Use this calculator for the precise value, then cross-check against the operator's posted number.