What does the Expected value calculator show?

It combines an entered probability with win profit and stake loss to show EV.

Should I treat the result as a forecast?

No. It is a calculation based on the values entered. Market rules, settlement and price movement can change how a real bet is settled.

Expected Value Calculator for Odds and True Probability

Last updated: 22 August 2026 Written by Ellie Marsden, Senior Betting Editor Fact checked by Tom Brackley, Odds Analyst

What this calculator answers

Estimate the average monetary result per bet from an entered price and your own probability estimate. It separates the possible profit on a win from the stake lost when the selection loses.

Formula and worked example

Formula: EV = probability multiplied by win profit minus (1 minus probability) multiplied by stake. Probability is entered as a percentage.

At 2.50, a 10.00 stake wins 15.00 profit. If estimated true probability is 45 percent, EV is 0.45 times 15.00 minus 0.55 times 10.00, or 1.25.

Checks before using the result

Using implied probability when the field asks for an independent estimate.
Entering 45 instead of 0.45 in a formula outside this calculator.
Treating a positive estimate as proof of a single outcome.

When the calculation does not apply

It depends completely on the probability estimate. A small error in that estimate can reverse the result, and one settlement does not reveal a long-run average.

Keep the number in context

A calculator makes the arithmetic visible, but it does not decide whether a price fits your budget or information. Write down the stake before placing anything, check the market rules, and keep essential money separate. The result is a planning figure, not a prediction of what will happen.

For another view, visit the calculator hub, compare the Closing line value and Margin of victory, or read the odds format guide. These tools use the same price conventions, so you can check a number from more than one angle.

Reading a rounded result

Displayed money amounts are rounded to two decimal places, while a real settlement can apply its own rounding sequence. Keep the original inputs beside the result if you need to repeat the calculation later.

If an input is unclear, pause and find the stated market term rather than guessing. A useful check is to change one input by a small amount and see whether the result moves in the direction you expect.

That does not validate the market, but it can reveal a reversed sign, an incorrect price format or a duplicated stake. Use the final figure as an aid to understanding the arithmetic, not as a reason to ignore a limit you set in advance.