{"id":354,"date":"2026-09-26T14:27:54","date_gmt":"2026-09-26T12:27:54","guid":{"rendered":"https:\/\/bankrollatlas.com\/fr\/outils\/kelly-calculator\/"},"modified":"2026-09-26T14:46:03","modified_gmt":"2026-09-26T12:46:03","slug":"kelly-calculator","status":"publish","type":"ba_tool","link":"https:\/\/bankrollatlas.com\/en\/tools\/kelly-calculator\/","title":{"rendered":"Kelly criterion and stake calculator"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">What this calculator does<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The Kelly criterion tells you what share of your bankroll to stake to grow it as fast as possible over time, provided your probability estimate is right. It puts a number on an intuition: the bigger the edge, the bigger the stake can be.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How to use it<\/h2>\n\n\n\n<ol class=\"wp-block-list ba-steps\">\n<li><strong>Enter the odds.<\/strong> In the format of your choice.<\/li>\n\n\n<li><strong>Give your estimate.<\/strong> The probability, as a percentage, that you assign to the outcome.<\/li>\n\n\n<li><strong>Enter your bankroll and unit.<\/strong> To get the stake as an amount and in units.<\/li>\n\n\n<li><strong>Choose a fraction.<\/strong> \u00bc Kelly by default, the most cautious setting.<\/li>\n\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">The formula<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Kelly fraction = (odds \u00d7 probability \u2212 1) \/ (odds \u2212 1).<\/li>\n\n\n<li>Stake = bankroll \u00d7 Kelly fraction \u00d7 chosen fraction.<\/li>\n\n\n<li>Stake in units = stake \/ unit value.<\/li>\n\n\n<li>Estimated edge = odds \u00d7 probability \u2212 1; break-even = 1 \/ odds.<\/li>\n\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Worked example<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Odds of 2.00, estimated probability 55%, bankroll 1,000, unit 10, \u00bc Kelly.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Step<\/th><th>Calculation<\/th><th>Result<\/th><\/tr><\/thead><tbody><tr><td>Estimated edge<\/td><td>2.00 \u00d7 0.55 \u2212 1<\/td><td>+10%<\/td><\/tr><tr><td>Full Kelly<\/td><td>(2.00 \u00d7 0.55 \u2212 1) \/ (2.00 \u2212 1)<\/td><td>10%<\/td><\/tr><tr><td>\u00bc Kelly<\/td><td>10% \u00d7 0.25<\/td><td>2.5%<\/td><\/tr><tr><td>Stake<\/td><td>1,000 \u00d7 2.5%<\/td><td>25<\/td><\/tr><tr><td>In units<\/td><td>25 \/ 10<\/td><td>2.5 u<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Why a fraction of Kelly<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Full Kelly assumes an exact estimate. Overrate a probability by just a few points and you stake far too much. Staking \u00bc or \u00bd Kelly sharply reduces bankroll swings for barely lower growth: that is the trade-off most disciplined bettors make.<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">If your estimate does not clear the break-even point, the suggested stake is zero. The calculator does not look for a bet where there is no edge.<\/p>\n<\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\">Limits<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The result is only as good as your estimate. For several bets placed at the same time, or bets that are linked, the simple formula overstates the stake: lower the fraction.<\/p>\n\n\n","protected":false},"excerpt":{"rendered":"<p>Size your stake from your odds, your probability estimate and your bankroll, with a cautious Kelly fraction.<\/p>\n","protected":false},"featured_media":0,"menu_order":2,"template":"","meta":{"ba_tool_widget":"kelly","ba_tool_family":"stake","footnotes":""},"class_list":["post-354","ba_tool","type-ba_tool","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.6 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Kelly Criterion Calculator: Optimal Stake in Units<\/title>\n<meta name=\"description\" content=\"Work out your optimal stake with the Kelly criterion: estimated probability, odds, Kelly fraction and stake in units of your bankroll. 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