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OddsRelay

Matched betting calculator

Free

Work out your lay stake, liability and locked profit in one place.

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index.html
<div data-or-widget="calculator"
     data-or-theme="dark"></div>
<script src="https://oddsrelay.io/widgets/oddsrelay-widgets.js" async></script>

Paste it once, anywhere. The script auto-mounts every data-or-widget element and is style-isolated in a Shadow DOM, so it never clashes with your CSS.

Installing on WordPress, Webflow, Squarespace, Wix or React?
WordPress
Add a Custom HTML block (or switch the classic editor to the Text tab) and paste the snippet.
Webflow
Drop in an Embed element, paste the snippet, and publish — the widget renders on the published site.
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Insert a Code block where you want the widget and paste the snippet as HTML.
Wix
Add an Embed HTML element (iFrame-free custom code) and paste the snippet.
React / Next.js
Render the div, then load the script once (e.g. next/script or an effect). The bundle auto-mounts new [data-or-widget] elements; call window.OddsRelay.scan() after client-side navigations if needed.

Back at the bookmaker, lay at the exchange, and lock the same result whichever way the bet lands. This calculator does the arithmetic for qualifying bets and for both kinds of free bet (stake-not-returned and stake-returned), so you always know the lay stake to place and exactly what you stand to keep.

What it does

  • Lay stake, liability and the result whether the back bet wins or loses
  • Qualifying bets plus SNR and SR free bets, with free-bet retention %
  • Underlay / overlay and penny, 10p or whole-pound rounding for real exchange stakes
  • Runs entirely in your browser — no account, nothing leaves the page

How to use it

  1. 1Enter your back bet. Type the back stake (or free-bet value) and the bookmaker's back odds.
  2. 2Enter the lay side. Add the exchange lay odds and your commission rate.
  3. 3Read off the lay stake. The calculator shows the lay stake, liability and the locked result instantly — one tap to copy.

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.

Questions

How is the lay stake calculated?
The lay stake balances both outcomes so your result is the same whether the back bet wins or loses. For a qualifying bet it is (back odds × back stake) ÷ (lay odds − commission); a stake-not-returned free bet uses (back odds − 1) in place of back odds.
What is liability?
Liability is the amount the exchange holds when you place a lay bet — the lay stake multiplied by (lay odds − 1). It is what you would lose at the exchange if the back bet wins.
Does this calculator need an account or send my data anywhere?
No. It is pure client-side maths. Nothing you type is sent to a server, and you do not need an account or API key to use it.

18+ · Data product for licensed operators. Please gamble responsibly.

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