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's arithmetic on the numbers you entered. Market rules, settlement mechanics and price movement all change how a real bet lands.

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 shows the arithmetic. It doesn't tell you whether the price fits your read of the outcome or your budget. Decide the stake before you enter it. Check the market rules. Keep essential money out of it entirely.

Cross-check on a second tool. The calculator hub, Closing line value or Margin of victory cover the same numbers from a different angle. Same price conventions, so a decimal price in one is a decimal price in the other.

Read the odds format guide if you're new to the formats. Two minutes.

Reading a rounded result

Money is rounded to two decimals here. A real settlement applies its own rounding sequence, which can differ. Keep the original inputs written down if you're going to check the number later.

Unclear about an input? Find the stated market term. Don't guess. A quick sanity check: change one input by a small amount and see whether the result moves the way you expect.

That doesn't validate the market. It can flag a reversed sign, a mis-entered price format or a duplicated stake. Use the number to understand the arithmetic. It's not a reason to ignore a limit you set in advance.