{"id":244,"date":"2026-08-21T18:30:33","date_gmt":"2026-08-21T18:30:33","guid":{"rendered":"https:\/\/netguide.io\/tools\/kreditkarten-pruefer-luhn\/"},"modified":"2026-08-21T18:30:33","modified_gmt":"2026-08-21T18:30:33","slug":"kreditkarten-pruefer-luhn","status":"publish","type":"post","link":"https:\/\/netguide.io\/tools\/de\/kreditkarten-pruefer-luhn\/","title":{"rendered":"Kreditkarten-Pr\u00fcfer (Luhn)"},"content":{"rendered":"<div id=\"netgu-1237047967\" class=\"netgu-before-content netgu-entity-placement\"><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-6258556257245998\" crossorigin=\"anonymous\"><\/script><ins class=\"adsbygoogle\" style=\"display:block;\" data-ad-client=\"ca-pub-6258556257245998\" \ndata-ad-slot=\"3494115342\" \ndata-ad-format=\"auto\"><\/ins>\n<script> \n(adsbygoogle = window.adsbygoogle || []).push({}); \n<\/script>\n<\/div>\n<style>\n.wp-luhn-container { max-width:100%; background:#fff; padding:20px; border:1px solid #ddd; border-radius:10px; font-family:-apple-system, sans-serif; color:#333; }\n.wp-luhn-title { margin:0 0 15px 0; color:#2271b1; font-size:1.4rem; }\n.wp-luhn-grid { display:grid; grid-template-columns:repeat(auto-fit, minmax(140px, 1fr)); gap:12px; margin-bottom:10px; }\n.wp-luhn-input-group label { display:block; font-size:11px; font-weight:bold; margin-bottom:4px; text-transform:uppercase; color:#666; }\n.wp-luhn-input-group input, .wp-luhn-input-group select { width:100%; padding:8px; border:1px solid #ccc; border-radius:4px; box-sizing:border-box; }\n.wp-luhn-checkbox-group { margin:15px 0; font-size:12px; display:flex; align-items:center; gap:8px; color:#666; }\n.wp-luhn-note { font-size:12px; color:#666; margin-top:12px; min-height:1em; }\n.wp-luhn-warn { color:#d63638; font-weight:bold; }\n.wp-luhn-results { margin-top:20px; border-top:2px solid #eee; padding-top:15px; }\n.wp-luhn-res-item { display:flex; justify-content:space-between; margin-bottom:6px; font-size:14px; gap:10px; }\n.wp-luhn-total { font-weight:bold; font-size:18px; color:#2271b1; margin:10px 0; padding:5px 0; border-top:1px solid #eee; border-bottom:1px solid #eee; }\n.wp-luhn-val { color:#2271b1; font-weight:bold; }\n.wp-luhn-out { width:100%; box-sizing:border-box; padding:10px; border:1px solid #ccc; border-radius:4px; font-family:monospace; font-size:13px; word-break:break-all; background:#f7f7f7; margin-top:6px; }\n.wp-luhn-btn { background:#2271b1; color:#fff; border:none; padding:9px 14px; border-radius:4px; cursor:pointer; font-size:13px; margin-top:10px; }\n<\/style><style>.wp-luhn-res{padding:12px;border-radius:6px;font-size:15px;font-weight:bold;margin-top:12px;background:#f9f9f9;border:1px solid #eee;min-height:1em;}.wp-luhn-res.ok{background:#e7f7ed;color:#2e7d32;border-color:#a5d6a7;}.wp-luhn-res.bad{background:#fdf2f2;color:#d32f2f;border-color:#ef9a9a;}<\/style><script>window.wpLuhnL = {\"waiting\":\"Nummer eingeben\u2026\",\"digits\":\"Nur Ziffern erlaubt\",\"type\":\"Typ\",\"digitsN\":\"Ziffern\",\"valid\":\"G\u00fcltig (Luhn-Pr\u00fcfung bestanden)\",\"invalid\":\"Ung\u00fcltig (Luhn-Pr\u00fcfung fehlgeschlagen)\"};<\/script>\n<div class=\"wp-luhn-container\">\n  <h3 class=\"wp-luhn-title\">Kreditkarten-Pr\u00fcfer (Luhn)<\/h3>\n  <div class=\"wp-luhn-input-group\"><label>Nummer<\/label><input type=\"text\" id=\"luhn-in\" value=\"4539 1488 0343 6467\" oninput=\"luhnCheck()\"><\/div>\n  <div id=\"luhn-res\" class=\"wp-luhn-res\"><\/div>\n  <div id=\"luhn-det\" class=\"wp-luhn-note\" style=\"margin-top:8px;\"><\/div>\n  <div class=\"wp-luhn-note\">Der Luhn-Test erkennt Tippfehler, sagt aber nichts dar\u00fcber aus, ob die Karte g\u00fcltig oder gedeckt ist. Alles lokal \u2013 keine \u00dcbertragung.<\/div>\n<\/div>\n<script>\nfunction luhnValid(n){ n=String(n).replace(\/\\s\/g,''); if(!\/^[0-9]+$\/.test(n))return false; var sum=0,alt=false; for(var i=n.length-1;i>=0;i--){ var d=parseInt(n[i],10); if(alt){ d=d*2; if(d>9)d-=9; } sum+=d; alt=!alt; } return sum%10===0; }\nfunction luhnCard(n){ n=n.replace(\/\\s\/g,''); if(\/^4\/.test(n))return 'Visa'; if(\/^(5[1-5]|2[2-7])\/.test(n))return 'Mastercard'; if(\/^3[47]\/.test(n))return 'American Express'; if(\/^6(011|5)\/.test(n))return 'Discover'; if(\/^3(0[0-5]|[68])\/.test(n))return 'Diners Club'; return '-'; }\nfunction luhnCheck(){\n  var raw=document.getElementById('luhn-in').value; var s=String(raw).replace(\/\\s\/g,''); var box=document.getElementById('luhn-res'); var det=document.getElementById('luhn-det'); var L=window.wpLuhnL||{};\n  if(!s){ box.className='wp-luhn-res'; box.innerText=L.waiting||''; det.innerText=''; return; }\n  if(!\/^[0-9]+$\/.test(s)){ box.className='wp-luhn-res bad'; box.innerText='\\u2717 '+(L.digits||'Digits only'); det.innerText=''; return; }\n  var ok=luhnValid(s);\n  det.innerText=(L.type||'Type')+': '+luhnCard(s)+'  \\u00b7  '+s.length+' '+(L.digitsN||'digits');\n  if(ok){ box.className='wp-luhn-res ok'; box.innerText='\\u2713 '+(L.valid||'Valid (Luhn check passed)'); }\n  else { box.className='wp-luhn-res bad'; box.innerText='\\u2717 '+(L.invalid||'Invalid (Luhn check failed)'); }\n}\nluhnCheck();\n<\/script>\n\n\n<div id=\"netgu-3736687347\"><script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-6258556257245998\"\r\n     crossorigin=\"anonymous\"><\/script>\r\n<!-- NetGuide.io-After-Widget-Tools -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:block\"\r\n     data-ad-client=\"ca-pub-6258556257245998\"\r\n     data-ad-slot=\"5175852350\"\r\n     data-ad-format=\"auto\"\r\n     data-full-width-responsive=\"true\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Der Luhn-Algorithmus<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Kreditkartennummern (und viele andere ID-Nummern) enthalten eine Pr\u00fcfziffer nach dem Luhn-Verfahren. Damit lassen sich Zahlendreher und Tippfehler erkennen. Der Pr\u00fcfer zeigt au\u00dferdem den erkannten Kartentyp anhand der Anfangsziffern.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Luhn-Pr\u00fcfung:<\/strong> Jede zweite Ziffer wird verdoppelt (Quersumme bei &gt; 9), alles summiert \u2013 die Summe muss durch 10 teilbar sein.<\/li>\n\n\n<li><strong>Kartentyp:<\/strong> Erkennung von Visa, Mastercard, American Express, Discover und Diners Club.<\/li>\n\n\n<li><strong>Wichtig:<\/strong> Der Test pr\u00fcft nur die Pr\u00fcfziffer, nicht die tats\u00e4chliche G\u00fcltigkeit der Karte.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Verwandte Tools<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"\/tools\/de\/iban-pruefer\/\">IBAN-Pr\u00fcfer<\/a><\/li>\n\n\n<li><a href=\"\/tools\/de\/passwort-leak-check\/\">Passwort-Leak-Check<\/a><\/li>\n<\/ul>\n\n\n<div id=\"netgu-1577756733\" class=\"netgu-after-content netgu-entity-placement\"><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-6258556257245998\" crossorigin=\"anonymous\"><\/script><ins class=\"adsbygoogle\" style=\"display:block;\" data-ad-client=\"ca-pub-6258556257245998\" \ndata-ad-slot=\"4559785002\" \ndata-ad-format=\"auto\"><\/ins>\n<script> \n(adsbygoogle = window.adsbygoogle || []).push({}); \n<\/script>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Kreditkarten- oder andere Nummern per Luhn-Algorithmus pr\u00fcfen \u2013 inkl. Kartentyp-Erkennung. L\u00e4uft lokal im Browser.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[115],"tags":[],"class_list":["post-244","post","type-post","status-publish","format-standard","hentry","category-validator"],"brizy_media":[],"_links":{"self":[{"href":"https:\/\/netguide.io\/tools\/wp-json\/wp\/v2\/posts\/244","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/netguide.io\/tools\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/netguide.io\/tools\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/netguide.io\/tools\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/netguide.io\/tools\/wp-json\/wp\/v2\/comments?post=244"}],"version-history":[{"count":0,"href":"https:\/\/netguide.io\/tools\/wp-json\/wp\/v2\/posts\/244\/revisions"}],"wp:attachment":[{"href":"https:\/\/netguide.io\/tools\/wp-json\/wp\/v2\/media?parent=244"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/netguide.io\/tools\/wp-json\/wp\/v2\/categories?post=244"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/netguide.io\/tools\/wp-json\/wp\/v2\/tags?post=244"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}