Matched betting calculator
Work out your lay stake, liability and locked profit in one place.
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.
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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
- 1Enter your back bet. Type the back stake (or free-bet value) and the bookmaker's back odds.
- 2Enter the lay side. Add the exchange lay odds and your commission rate.
- 3Read off the lay stake. The calculator shows the lay stake, liability and the locked result instantly.
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 matched betting 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="calculator" data-or-calculator="standard" data-or-theme="light"></div>
<script src="https://oddsrelay.io/widgets/oddsrelay-widgets.js" async></script>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.
Building a betting product?
These calculators are free to use and free to embed. When you need the feed behind them — matched, rated, bet365 included — start a free trial or get in touch.