diff --git a/templates/index.html b/templates/index.html
index 7f0c6f2..873aa9b 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -304,6 +304,29 @@
                     {% endif %}
                 </div>
             </div>
+            <div class="accordion-item">
+                <button type="button" class="accordion-header header-kw" onclick="openAccordion(6)">
+                    <span style="vertical-align:middle;display:inline-block;width:1.5em;">
+                        <!-- Kalender mit # -->
+                        <svg width="24" height="24" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg"><rect x="3" y="5" width="18" height="16" rx="4" fill="#fff" stroke="#2563eb" stroke-width="2"/><rect x="3" y="5" width="18" height="4" rx="2" fill="#2563eb"/><rect x="6" y="2" width="2" height="4" rx="1" fill="#2563eb"/><rect x="16" y="2" width="2" height="4" rx="1" fill="#2563eb"/><text x="12" y="17" text-anchor="middle" font-size="13" font-family="Segoe UI, Arial, sans-serif" fill="#2563eb" font-weight="bold">#</text></svg>
+                    </span>
+                    Kalenderwoche eines Datums
+                </button>
+                <div class="accordion-content">
+                    <form method="post">
+                        <label>Datum:<br>
+                            <span class="date-row">
+                                <input type="date" name="datum6" id="datum6">
+                                <button type="button" class="today-btn" onclick="setToday('datum6')">Heute</button>
+                            </span>
+                        </label>
+                        <button name="action" value="kw_berechnen" type="submit">Kalenderwoche berechnen</button>
+                    </form>
+                    {% if kw_berechnen is not none %}
+                        <div class="result">Kalenderwoche von <b>{{ format_date(request.form.get('datum6', '')) }}</b>: {{ kw_berechnen }}</div>
+                    {% endif %}
+                </div>
+            </div>
             <div class="accordion-item">
                 <button type="button" class="accordion-header header-kw" onclick="openAccordion(6)">
                     <span style="vertical-align:middle;display:inline-block;width:1.5em;">