diff --git a/frontend/src/app/(app)/fristen/rechner/page.tsx b/frontend/src/app/(app)/fristen/rechner/page.tsx
index f4c3f75..29ac2b3 100644
--- a/frontend/src/app/(app)/fristen/rechner/page.tsx
+++ b/frontend/src/app/(app)/fristen/rechner/page.tsx
@@ -1,61 +1,29 @@
 "use client";
 
-import { DeadlineCalculator } from "@/components/deadlines/DeadlineCalculator";
-import { DeadlineWizard } from "@/components/deadlines/DeadlineWizard";
+import { FristenRechner } from "@/components/deadlines/FristenRechner";
 import { ArrowLeft } from "lucide-react";
 import Link from "next/link";
-import { useState } from "react";
 
 export default function FristenrechnerPage() {
-  const [mode, setMode] = useState<"wizard" | "quick">("wizard");
-
   return (
     <div className="animate-fade-in space-y-4">
-      <div className="flex items-start justify-between">
-        <div>
-          <Link
-            href="/fristen"
-            className="mb-2 inline-flex items-center gap-1 text-sm text-neutral-500 transition-colors hover:text-neutral-700"
-          >
-            <ArrowLeft className="h-3.5 w-3.5" />
-            Zurueck zu Fristen
-          </Link>
-          <h1 className="text-lg font-semibold text-neutral-900">
-            Fristenbestimmung
-          </h1>
-          <p className="mt-0.5 text-sm text-neutral-500">
-            {mode === "wizard"
-              ? "Vollstaendige Verfahrens-Timeline mit automatischer Fristenberechnung"
-              : "Schnellberechnung einzelner Fristen nach Verfahrensart"}
-          </p>
-        </div>
-
-        {/* Mode toggle */}
-        <div className="flex rounded-md border border-neutral-200 bg-neutral-50 p-0.5">
-          <button
-            onClick={() => setMode("wizard")}
-            className={`rounded px-3 py-1 text-xs font-medium transition-colors ${
-              mode === "wizard"
-                ? "bg-white text-neutral-900 shadow-sm"
-                : "text-neutral-500 hover:text-neutral-700"
-            }`}
-          >
-            Verfahren
-          </button>
-          <button
-            onClick={() => setMode("quick")}
-            className={`rounded px-3 py-1 text-xs font-medium transition-colors ${
-              mode === "quick"
-                ? "bg-white text-neutral-900 shadow-sm"
-                : "text-neutral-500 hover:text-neutral-700"
-            }`}
-          >
-            Schnell
-          </button>
-        </div>
+      <div>
+        <Link
+          href="/fristen"
+          className="mb-2 inline-flex items-center gap-1 text-sm text-neutral-500 transition-colors hover:text-neutral-700"
+        >
+          <ArrowLeft className="h-3.5 w-3.5" />
+          Zurueck zu Fristen
+        </Link>
+        <h1 className="text-lg font-semibold text-neutral-900">
+          Fristenrechner
+        </h1>
+        <p className="mt-0.5 text-sm text-neutral-500">
+          Verfahrensart waehlen, Fristen einsehen und Termine berechnen
+        </p>
       </div>
 
-      {mode === "wizard" ? <DeadlineWizard /> : <DeadlineCalculator />}
+      <FristenRechner />
     </div>
   );
 }
diff --git a/frontend/src/components/deadlines/FristenRechner.tsx b/frontend/src/components/deadlines/FristenRechner.tsx
new file mode 100644
index 0000000..40ffccc
--- /dev/null
+++ b/frontend/src/components/deadlines/FristenRechner.tsx
@@ -0,0 +1,602 @@
+"use client";
+
+import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
+import { api } from "@/lib/api";
+import type {
+  ProceedingType,
+  RuleTreeNode,
+  CalculateResponse,
+  Case,
+} from "@/lib/types";
+import { format, parseISO } from "date-fns";
+import { de } from "date-fns/locale";
+import {
+  Scale,
+  Users,
+  Gavel,
+  FileText,
+  Clock,
+  CalendarDays,
+  AlertTriangle,
+  ChevronRight,
+  RotateCcw,
+  Loader2,
+  Check,
+  FolderOpen,
+} from "lucide-react";
+import { useState, useMemo } from "react";
+import { toast } from "sonner";
+
+// --- Helpers ---
+
+function formatDuration(value: number, unit: string): string {
+  if (value === 0) return "";
+  const labels: Record<string, string> = {
+    days: value === 1 ? "Tag" : "Tage",
+    weeks: value === 1 ? "Woche" : "Wochen",
+    months: value === 1 ? "Monat" : "Monate",
+  };
+  return `${value} ${labels[unit] || unit}`;
+}
+
+function getPartyIcon(party?: string) {
+  switch (party) {
+    case "claimant":
+      return <Scale className="h-3.5 w-3.5" />;
+    case "defendant":
+      return <Users className="h-3.5 w-3.5" />;
+    case "court":
+      return <Gavel className="h-3.5 w-3.5" />;
+    default:
+      return <FileText className="h-3.5 w-3.5" />;
+  }
+}
+
+function getPartyLabel(party?: string): string {
+  switch (party) {
+    case "claimant":
+      return "Klaeger";
+    case "defendant":
+      return "Beklagter";
+    case "court":
+      return "Gericht";
+    case "both":
+      return "Beide Parteien";
+    default:
+      return "";
+  }
+}
+
+interface FlatRule {
+  id: string;
+  name: string;
+  duration_value: number;
+  duration_unit: string;
+  rule_code?: string;
+  primary_party?: string;
+  event_type?: string;
+  is_mandatory: boolean;
+  deadline_notes?: string;
+  description?: string;
+  depth: number;
+}
+
+function flattenRuleTree(nodes: RuleTreeNode[], depth = 0): FlatRule[] {
+  const result: FlatRule[] = [];
+  for (const node of nodes) {
+    result.push({
+      id: node.id,
+      name: node.name,
+      duration_value: node.duration_value,
+      duration_unit: node.duration_unit,
+      rule_code: node.rule_code,
+      primary_party: node.primary_party,
+      event_type: node.event_type,
+      is_mandatory: node.is_mandatory,
+      deadline_notes: node.deadline_notes,
+      description: node.description,
+      depth,
+    });
+    if (node.children && node.children.length > 0) {
+      result.push(...flattenRuleTree(node.children, depth + 1));
+    }
+  }
+  return result;
+}
+
+// --- Group labels ---
+
+const categoryLabels: Record<string, string> = {
+  hauptverfahren: "Hauptverfahren",
+  im_verfahren: "Verfahren im Verfahren",
+  rechtsbehelf: "Rechtsbehelfe",
+};
+
+const jurisdictionLabels: Record<string, string> = {
+  UPC: "UPC",
+  DE: "Deutsche Patentverfahren",
+};
+
+interface TypeGroup {
+  key: string;
+  label: string;
+  items: ProceedingType[];
+}
+
+function groupProceedingTypes(types: ProceedingType[]): TypeGroup[] {
+  const groups: TypeGroup[] = [];
+  const seen = new Set<string>();
+  for (const pt of types) {
+    const j = pt.jurisdiction ?? "Sonstige";
+    const c = pt.category ?? "hauptverfahren";
+    const key = `${j}::${c}`;
+    if (!seen.has(key)) {
+      seen.add(key);
+      const jLabel = jurisdictionLabels[j] ?? j;
+      const cLabel = categoryLabels[c] ?? c;
+      const label = j === "DE" ? jLabel : `${jLabel} — ${cLabel}`;
+      groups.push({ key, label, items: [] });
+    }
+    groups.find((g) => g.key === key)!.items.push(pt);
+  }
+  return groups;
+}
+
+// --- Main Component ---
+
+export function FristenRechner() {
+  const [selectedType, setSelectedType] = useState<string | null>(null);
+  const [expandedRuleId, setExpandedRuleId] = useState<string | null>(null);
+  const [triggerDate, setTriggerDate] = useState(
+    new Date().toISOString().split("T")[0],
+  );
+  const [calcResults, setCalcResults] = useState<
+    Record<string, { due_date: string; original_due_date: string; was_adjusted: boolean }>
+  >({});
+  const [savingRuleId, setSavingRuleId] = useState<string | null>(null);
+  const [selectedCaseId, setSelectedCaseId] = useState<string>("");
+  const queryClient = useQueryClient();
+
+  // Fetch proceeding types
+  const { data: proceedingTypes, isLoading: typesLoading } = useQuery({
+    queryKey: ["proceeding-types"],
+    queryFn: () => api.get<ProceedingType[]>("/proceeding-types"),
+  });
+
+  // Fetch rule tree when type is selected
+  const { data: ruleTree, isLoading: rulesLoading } = useQuery({
+    queryKey: ["deadline-rules", selectedType],
+    queryFn: () => api.get<RuleTreeNode[]>(`/deadline-rules/${selectedType}`),
+    enabled: !!selectedType,
+  });
+
+  // Fetch cases for "save to case"
+  const { data: cases } = useQuery({
+    queryKey: ["cases"],
+    queryFn: () => api.get<Case[]>("/cases"),
+    enabled: savingRuleId !== null,
+  });
+
+  // Calculate single deadline
+  const calcMutation = useMutation({
+    mutationFn: (params: {
+      proceeding_type: string;
+      trigger_event_date: string;
+      selected_rule_ids: string[];
+    }) => api.post<CalculateResponse>("/deadlines/calculate", params),
+    onSuccess: (data, variables) => {
+      if (data.deadlines && data.deadlines.length > 0) {
+        const d = data.deadlines[0];
+        setCalcResults((prev) => ({
+          ...prev,
+          [variables.selected_rule_ids[0]]: {
+            due_date: d.due_date,
+            original_due_date: d.original_due_date,
+            was_adjusted: d.was_adjusted,
+          },
+        }));
+      }
+    },
+  });
+
+  // Save deadline to case
+  const saveMutation = useMutation({
+    mutationFn: (params: {
+      caseId: string;
+      deadline: { title: string; due_date: string; original_due_date?: string; rule_code?: string };
+    }) =>
+      api.post(`/cases/${params.caseId}/deadlines`, {
+        title: params.deadline.title,
+        due_date: params.deadline.due_date,
+        original_due_date: params.deadline.original_due_date,
+        rule_code: params.deadline.rule_code,
+        source: "calculator",
+      }),
+    onSuccess: () => {
+      toast.success("Frist auf Akte gespeichert");
+      queryClient.invalidateQueries({ queryKey: ["deadlines"] });
+      setSavingRuleId(null);
+      setSelectedCaseId("");
+    },
+    onError: () => {
+      toast.error("Fehler beim Speichern");
+    },
+  });
+
+  // Flat list of rules
+  const flatRules = useMemo(() => {
+    if (!ruleTree) return [];
+    return flattenRuleTree(ruleTree);
+  }, [ruleTree]);
+
+  // Groups
+  const groups = useMemo(() => {
+    if (!proceedingTypes) return [];
+    return groupProceedingTypes(proceedingTypes);
+  }, [proceedingTypes]);
+
+  const selectedPT = proceedingTypes?.find((pt) => pt.code === selectedType);
+
+  function handleTypeSelect(code: string) {
+    setSelectedType(code);
+    setExpandedRuleId(null);
+    setCalcResults({});
+    setSavingRuleId(null);
+  }
+
+  function handleReset() {
+    setSelectedType(null);
+    setExpandedRuleId(null);
+    setCalcResults({});
+    setSavingRuleId(null);
+    setSelectedCaseId("");
+  }
+
+  function handleRuleClick(ruleId: string) {
+    if (expandedRuleId === ruleId) {
+      setExpandedRuleId(null);
+      return;
+    }
+    setExpandedRuleId(ruleId);
+    setSavingRuleId(null);
+    // Auto-calculate with current date
+    if (selectedType && triggerDate) {
+      calcMutation.mutate({
+        proceeding_type: selectedType,
+        trigger_event_date: triggerDate,
+        selected_rule_ids: [ruleId],
+      });
+    }
+  }
+
+  function handleDateChange(ruleId: string, date: string) {
+    setTriggerDate(date);
+    if (selectedType && date) {
+      calcMutation.mutate({
+        proceeding_type: selectedType,
+        trigger_event_date: date,
+        selected_rule_ids: [ruleId],
+      });
+    }
+  }
+
+  return (
+    <div className="space-y-6">
+      {/* Step 1: Proceeding Type Cards */}
+      <div>
+        <div className="mb-4 flex items-center justify-between">
+          <h2 className="text-sm font-medium text-neutral-900">
+            Verfahrensart waehlen
+          </h2>
+          {selectedType && (
+            <button
+              onClick={handleReset}
+              className="flex items-center gap-1 text-xs text-neutral-500 hover:text-neutral-700"
+            >
+              <RotateCcw className="h-3 w-3" />
+              Zuruecksetzen
+            </button>
+          )}
+        </div>
+
+        {typesLoading ? (
+          <div className="flex justify-center py-8">
+            <Loader2 className="h-5 w-5 animate-spin text-neutral-400" />
+          </div>
+        ) : (
+          <div className="space-y-5">
+            {groups.map((group) => (
+              <div key={group.key}>
+                <div className="mb-2 text-xs font-medium uppercase tracking-wide text-neutral-400">
+                  {group.label}
+                </div>
+                <div className="flex flex-wrap gap-2">
+                  {group.items.map((pt) => {
+                    const isSelected = selectedType === pt.code;
+                    return (
+                      <button
+                        key={pt.id}
+                        onClick={() => handleTypeSelect(pt.code)}
+                        className={`rounded-lg border px-3 py-2 text-sm transition-all ${
+                          isSelected
+                            ? "border-neutral-900 bg-neutral-900 text-white shadow-sm"
+                            : "border-neutral-200 bg-white text-neutral-700 hover:border-neutral-300 hover:shadow-sm"
+                        }`}
+                      >
+                        {pt.name}
+                      </button>
+                    );
+                  })}
+                </div>
+              </div>
+            ))}
+          </div>
+        )}
+      </div>
+
+      {/* Step 2: Deadline Rules for Selected Type */}
+      {selectedType && (
+        <div className="animate-fade-in">
+          <div className="mb-3 flex items-center justify-between">
+            <div>
+              <h2 className="text-sm font-medium text-neutral-900">
+                Fristen: {selectedPT?.name}
+              </h2>
+              {flatRules.length > 0 && (
+                <p className="mt-0.5 text-xs text-neutral-500">
+                  {flatRules.length} Fristen &mdash; Frist anklicken zum Berechnen
+                </p>
+              )}
+            </div>
+          </div>
+
+          {rulesLoading ? (
+            <div className="flex justify-center py-8">
+              <Loader2 className="h-5 w-5 animate-spin text-neutral-400" />
+            </div>
+          ) : flatRules.length === 0 ? (
+            <div className="rounded-lg border border-dashed border-neutral-300 bg-white px-6 py-8 text-center text-sm text-neutral-500">
+              Keine Fristenregeln fuer diesen Verfahrenstyp hinterlegt.
+            </div>
+          ) : (
+            <div className="rounded-lg border border-neutral-200 bg-white divide-y divide-neutral-100">
+              {flatRules.map((rule, i) => {
+                const isExpanded = expandedRuleId === rule.id;
+                const result = calcResults[rule.id];
+                const duration = formatDuration(rule.duration_value, rule.duration_unit);
+
+                return (
+                  <div key={rule.id}>
+                    {/* Rule Row */}
+                    <button
+                      onClick={() => handleRuleClick(rule.id)}
+                      className={`flex w-full items-center gap-3 px-4 py-3 text-left transition-colors hover:bg-neutral-50 ${
+                        isExpanded ? "bg-neutral-50" : ""
+                      }`}
+                      style={{ paddingLeft: `${16 + rule.depth * 20}px` }}
+                    >
+                      {/* Timeline dot + connector */}
+                      <div className="flex flex-col items-center">
+                        <div
+                          className={`h-2.5 w-2.5 shrink-0 rounded-full border-2 ${
+                            isExpanded
+                              ? "border-neutral-900 bg-neutral-900"
+                              : "border-neutral-300 bg-white"
+                          }`}
+                        />
+                        {i < flatRules.length - 1 && (
+                          <div className="mt-0.5 h-3 w-px bg-neutral-200" />
+                        )}
+                      </div>
+
+                      {/* Content */}
+                      <div className="min-w-0 flex-1">
+                        <div className="flex items-center gap-2">
+                          <span className="text-sm font-medium text-neutral-900">
+                            {rule.name}
+                          </span>
+                          {!rule.is_mandatory && (
+                            <span className="rounded bg-neutral-100 px-1 py-0.5 text-[10px] text-neutral-400">
+                              optional
+                            </span>
+                          )}
+                        </div>
+                        <div className="mt-0.5 flex flex-wrap items-center gap-x-2 gap-y-0.5 text-xs text-neutral-500">
+                          {duration && (
+                            <span className="flex items-center gap-0.5">
+                              <Clock className="h-3 w-3" />
+                              {duration}
+                            </span>
+                          )}
+                          {rule.rule_code && (
+                            <>
+                              <span className="text-neutral-300">&middot;</span>
+                              <span className="rounded bg-neutral-100 px-1 py-0.5 font-mono text-[10px]">
+                                {rule.rule_code}
+                              </span>
+                            </>
+                          )}
+                          {rule.primary_party && (
+                            <>
+                              <span className="text-neutral-300">&middot;</span>
+                              <span className="flex items-center gap-0.5">
+                                {getPartyIcon(rule.primary_party)}
+                                {getPartyLabel(rule.primary_party)}
+                              </span>
+                            </>
+                          )}
+                        </div>
+                      </div>
+
+                      {/* Chevron */}
+                      <ChevronRight
+                        className={`h-4 w-4 shrink-0 text-neutral-400 transition-transform ${
+                          isExpanded ? "rotate-90" : ""
+                        }`}
+                      />
+                    </button>
+
+                    {/* Step 3: Expanded Calculation Panel */}
+                    {isExpanded && (
+                      <div className="border-t border-neutral-100 bg-neutral-50 px-4 py-4 animate-fade-in"
+                        style={{ paddingLeft: `${36 + rule.depth * 20}px` }}
+                      >
+                        <div className="flex flex-col gap-4 sm:flex-row sm:items-end">
+                          {/* Date picker */}
+                          <div>
+                            <label className="mb-1 block text-xs font-medium text-neutral-500">
+                              Ausloesedatum
+                            </label>
+                            <input
+                              type="date"
+                              value={triggerDate}
+                              onChange={(e) =>
+                                handleDateChange(rule.id, e.target.value)
+                              }
+                              className="rounded-md border border-neutral-200 bg-white px-3 py-2 text-sm text-neutral-900 outline-none transition-colors focus:border-neutral-400 focus:ring-1 focus:ring-neutral-400"
+                            />
+                          </div>
+
+                          {/* Result */}
+                          {calcMutation.isPending &&
+                            calcMutation.variables?.selected_rule_ids[0] === rule.id ? (
+                            <div className="flex items-center gap-2 text-sm text-neutral-500">
+                              <Loader2 className="h-4 w-4 animate-spin" />
+                              Berechne...
+                            </div>
+                          ) : result ? (
+                            <div className="flex items-center gap-4">
+                              <div>
+                                <div className="text-xs font-medium text-neutral-500">
+                                  Fristende
+                                </div>
+                                <div className="flex items-center gap-2">
+                                  <CalendarDays className="h-4 w-4 text-neutral-700" />
+                                  <span className="text-lg font-semibold tabular-nums text-neutral-900">
+                                    {format(
+                                      parseISO(result.due_date),
+                                      "dd. MMMM yyyy",
+                                      { locale: de },
+                                    )}
+                                  </span>
+                                </div>
+                                {result.was_adjusted && (
+                                  <div className="mt-0.5 flex items-center gap-1 text-xs text-amber-600">
+                                    <AlertTriangle className="h-3 w-3" />
+                                    Angepasst (Original:{" "}
+                                    {format(
+                                      parseISO(result.original_due_date),
+                                      "dd.MM.yyyy",
+                                    )}
+                                    )
+                                  </div>
+                                )}
+                              </div>
+
+                              {/* Save to case button */}
+                              <button
+                                onClick={(e) => {
+                                  e.stopPropagation();
+                                  setSavingRuleId(
+                                    savingRuleId === rule.id ? null : rule.id,
+                                  );
+                                }}
+                                className="flex items-center gap-1 rounded-md border border-neutral-200 bg-white px-2.5 py-1.5 text-xs font-medium text-neutral-700 transition-colors hover:bg-neutral-50"
+                              >
+                                <FolderOpen className="h-3.5 w-3.5" />
+                                Auf Akte
+                              </button>
+                            </div>
+                          ) : null}
+                        </div>
+
+                        {/* Save to case panel */}
+                        {savingRuleId === rule.id && result && (
+                          <div className="mt-3 flex items-center gap-2 animate-fade-in">
+                            <select
+                              value={selectedCaseId}
+                              onChange={(e) =>
+                                setSelectedCaseId(e.target.value)
+                              }
+                              className="flex-1 rounded-md border border-neutral-200 bg-white px-3 py-1.5 text-xs text-neutral-900 outline-none focus:border-neutral-400"
+                            >
+                              <option value="">Akte waehlen...</option>
+                              {cases
+                                ?.filter((c) => c.status !== "closed")
+                                .map((c) => (
+                                  <option key={c.id} value={c.id}>
+                                    {c.case_number} — {c.title}
+                                  </option>
+                                ))}
+                            </select>
+                            <button
+                              disabled={
+                                !selectedCaseId || saveMutation.isPending
+                              }
+                              onClick={() => {
+                                saveMutation.mutate({
+                                  caseId: selectedCaseId,
+                                  deadline: {
+                                    title: rule.name,
+                                    due_date: result.due_date,
+                                    original_due_date: result.was_adjusted
+                                      ? result.original_due_date
+                                      : undefined,
+                                    rule_code: rule.rule_code,
+                                  },
+                                });
+                              }}
+                              className="flex items-center gap-1 rounded-md bg-neutral-900 px-3 py-1.5 text-xs font-medium text-white transition-colors hover:bg-neutral-800 disabled:opacity-50"
+                            >
+                              {saveMutation.isPending ? (
+                                <Loader2 className="h-3 w-3 animate-spin" />
+                              ) : (
+                                <Check className="h-3 w-3" />
+                              )}
+                              Speichern
+                            </button>
+                          </div>
+                        )}
+
+                        {/* Notes */}
+                        {rule.deadline_notes && (
+                          <p className="mt-2 text-xs italic text-neutral-400">
+                            {rule.deadline_notes}
+                          </p>
+                        )}
+                      </div>
+                    )}
+                  </div>
+                );
+              })}
+            </div>
+          )}
+        </div>
+      )}
+
+      {/* Empty state */}
+      {!selectedType && !typesLoading && (
+        <div className="flex flex-col items-center rounded-lg border border-dashed border-neutral-300 bg-white px-6 py-12 text-center">
+          <div className="rounded-xl bg-neutral-100 p-3">
+            <Scale className="h-6 w-6 text-neutral-400" />
+          </div>
+          <p className="mt-3 text-sm font-medium text-neutral-700">
+            Fristenrechner
+          </p>
+          <p className="mt-1 max-w-sm text-xs text-neutral-500">
+            Waehlen Sie oben eine Verfahrensart, um alle zugehoerigen Fristen
+            anzuzeigen und einzelne Termine zu berechnen.
+          </p>
+        </div>
+      )}
+
+      {/* Calculation error */}
+      {calcMutation.isError && (
+        <div className="flex items-center gap-2 rounded-lg border border-red-200 bg-red-50 px-4 py-3 text-sm text-red-700">
+          <AlertTriangle className="h-4 w-4 shrink-0" />
+          Fehler bei der Berechnung. Bitte Eingaben pruefen.
+        </div>
+      )}
+    </div>
+  );
+}