American odds explained: positive and negative prices

Read the sign before calculating

At +150, 100 units of stake would produce 150 units of profit on a normal win. At −200, 200 units of stake would produce 100 units of profit. The negative sign does not indicate negative winnings; it changes how the number describes the price.

This guide uses fictional ten-unit stakes, no fees and simple winning settlements. It is an explanation of odds notation, not a selection or staking recommendation.

Positive odds formula

For positive odds A, profit equals stake × A ÷ 100. At +150 with ten units: 10 × 150 ÷ 100 = 15 units of profit. Total return is 15 + 10 = 25 units.

The decimal equivalent is 1 + A ÷ 100. Therefore +150 becomes 2.50. At +100, the example profit equals the stake and the decimal equivalent is 2.00.

Negative odds formula

For negative odds with absolute value A, profit equals stake × 100 ÷ A. At −200 with ten units: 10 × 100 ÷ 200 = 5 units of profit. Total return is 15 units.

The decimal equivalent is 1 + 100 ÷ A, so −200 becomes 1.50. Use the absolute value in the denominator; inserting a negative amount would produce the wrong sign.

Check the examples

American odds	Decimal equivalent	Profit on 10 units	Total return
+100	2.00	10 units	20 units
+150	2.50	15 units	25 units
−200	1.50	5 units	15 units

Implied probability for positive odds is 100 ÷ (A + 100). For negative odds it is A ÷ (A + 100), using the absolute value. The price implies a percentage; it does not verify the event’s true chance.

Watch the boundaries

Real settlement may include fees, ties, voids or partial outcomes. The calculation above concerns a full win only. An American display does not tell you which settlement rules apply to a market.

Use the market explanation alongside the odds explanation. Before comparing prices, confirm the same selection, event and settlement scope. A familiar odds format cannot compensate for reading a different market as if it were the same one.