Bookmaker Margin Calculator
Measure the overround (juice) baked into any market.
How the Bookmaker Margin Calculator works
Sum the implied probabilities of each side. Anything above 100% is the book’s margin.
Every result updates instantly in your browser — nothing is sent to a server, and you can share the URL to save your setup.
When to use it
Use this tool any time you want to double-check a bookmaker's pricing, size a bet correctly, or convert between the odds format your book displays and the format you think in.
Related Xtabet tools
Xtabet ships a full toolbox of betting calculators. Browse the /tools index for the complete list of odds converters, EV calculators and staking planners.
Frequently asked questions
Is this Bookmaker Margin Calculator free?+
Yes — every Xtabet calculator is free and runs entirely in your browser.
Which odds format does it use?+
You can enter decimal or American odds — the tool auto-detects and normalises internally.
Does Xtabet store the numbers I enter?+
No. The maths runs client-side; nothing you type leaves your device.
Read more on Xtabet
Xtabet tools are for informational use only. 18+. Bet responsibly.