Expected value (EV) calculator
Turn your probability estimate into expected profit and an edge.
Value betting comes down to one question: is the price longer than the true chance deserves? Put in the offered odds, your own probability estimate and a stake, and the calculator returns the expected value of the bet, your percentage edge, and the fair odds your estimate implies.
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What it does
- Expected value in cash and as a percentage edge
- Fair odds for your probability estimate
- The probability the offered price implies
- A clear value / no-value verdict
How to use it
- 1Enter the odds. Type the decimal odds being offered.
- 2Add your probability. Enter your estimate of the true win chance as a percentage.
- 3Read the edge. See the expected value, your edge and the fair odds.
What powers this
This calculator runs entirely in your browser. There's no account, no API key and no feed — nothing you type leaves the page. The maths is the same commodity matched-betting and value arithmetic used across the industry, implemented carefully and unit-tested.
Embed it on your site
Paste this where you want the expected value calculator to appear. The script auto-mounts every widget on the page; swap data-or-theme for light, dark or transparent.
<div data-or-widget="ev" data-or-theme="light"></div>
<script src="https://oddsrelay.io/widgets/oddsrelay-widgets.js" async></script>Questions
- How is expected value calculated?
- Expected value = stake × (your probability × odds − 1). When your probability times the decimal odds is greater than 1, the bet has positive expected value.
- What are 'fair odds'?
- Fair odds are the break-even price for your probability estimate: 1 ÷ probability. If the offered odds are longer than the fair odds, the bet is value.
- Where does the probability estimate come from?
- That's your input — it's your model, your read of the market, or a sharper book's price converted to a probability. The calculator turns that estimate into an edge; it doesn't predict outcomes for you.
18+ · Data product for licensed operators. Please gamble responsibly.
Building a betting product?
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