diff --git a/resources/js/admin/mobile/EventAnalyticsPage.tsx b/resources/js/admin/mobile/EventAnalyticsPage.tsx
index 31c9d08..307321e 100644
--- a/resources/js/admin/mobile/EventAnalyticsPage.tsx
+++ b/resources/js/admin/mobile/EventAnalyticsPage.tsx
@@ -13,7 +13,7 @@ import { MobileCard, CTAButton, KpiTile, SkeletonCard } from './components/Primi
 import { getEventAnalytics, EventAnalytics } from '../api';
 import { ApiError } from '../lib/apiError';
 import { useAdminTheme } from './theme';
-import { resolveMaxCount } from './lib/analytics';
+import { resolveMaxCount, resolveTimelineHours } from './lib/analytics';
 import { adminPath } from '../constants';
 
 export default function MobileEventAnalyticsPage() {
@@ -98,7 +98,7 @@ export default function MobileEventAnalyticsPage() {
   const hasTimeline = timeline.length > 0;
   const hasContributors = contributors.length > 0;
   const hasTasks = tasks.length > 0;
-  const timeframeHours = 12;
+  const timeframeHours = resolveTimelineHours(timeline.map((point) => point.timestamp), 12);
 
   // Prepare chart data
   const maxTimelineCount = resolveMaxCount(timeline.map((point) => point.count));
diff --git a/resources/js/admin/mobile/__tests__/analytics.test.ts b/resources/js/admin/mobile/__tests__/analytics.test.ts
index e332270..9834085 100644
--- a/resources/js/admin/mobile/__tests__/analytics.test.ts
+++ b/resources/js/admin/mobile/__tests__/analytics.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { resolveMaxCount } from '../lib/analytics';
+import { resolveMaxCount, resolveTimelineHours } from '../lib/analytics';
 
 describe('resolveMaxCount', () => {
   it('defaults to 1 for empty input', () => {
@@ -14,3 +14,20 @@ describe('resolveMaxCount', () => {
     expect(resolveMaxCount([0])).toBe(1);
   });
 });
+
+describe('resolveTimelineHours', () => {
+  it('uses fallback when data is missing', () => {
+    expect(resolveTimelineHours([], 12)).toBe(12);
+  });
+
+  it('calculates rounded hours from timestamps', () => {
+    const start = new Date('2024-01-01T10:00:00Z').toISOString();
+    const end = new Date('2024-01-01T21:00:00Z').toISOString();
+    expect(resolveTimelineHours([start, end], 12)).toBe(11);
+  });
+
+  it('never returns less than 1', () => {
+    const start = new Date('2024-01-01T10:00:00Z').toISOString();
+    expect(resolveTimelineHours([start, start], 12)).toBe(1);
+  });
+});
diff --git a/resources/js/admin/mobile/lib/analytics.ts b/resources/js/admin/mobile/lib/analytics.ts
index cf2e9b4..9af13b9 100644
--- a/resources/js/admin/mobile/lib/analytics.ts
+++ b/resources/js/admin/mobile/lib/analytics.ts
@@ -5,3 +5,24 @@ export function resolveMaxCount(values: number[]): number {
 
   return Math.max(...values, 1);
 }
+
+export function resolveTimelineHours(timestamps: string[], fallbackHours = 12): number {
+  if (!Array.isArray(timestamps) || timestamps.length < 2) {
+    return fallbackHours;
+  }
+
+  const times = timestamps
+    .map((value) => new Date(value).getTime())
+    .filter((value) => Number.isFinite(value));
+
+  if (times.length < 2) {
+    return fallbackHours;
+  }
+
+  const min = Math.min(...times);
+  const max = Math.max(...times);
+  const diff = Math.max(0, max - min);
+  const hours = diff / (1000 * 60 * 60);
+
+  return Math.max(1, Math.round(hours));
+}