diff --git a/frontend/src/components/ContactInfoPane.tsx b/frontend/src/components/ContactInfoPane.tsx
index 65b9cf9..6d1a565 100644
--- a/frontend/src/components/ContactInfoPane.tsx
+++ b/frontend/src/components/ContactInfoPane.tsx
@@ -23,6 +23,13 @@ const CONTACT_TYPE_LABELS: Record<number, string> = {
   4: 'Sensor',
 };
 
+function formatPathHashMode(mode: number): string | null {
+  if (mode < 0 || mode > 2) {
+    return null;
+  }
+  return `${mode + 1}-byte IDs`;
+}
+
 interface ContactInfoPaneProps {
   contactKey: string | null;
   fromChannel?: boolean;
@@ -99,6 +106,7 @@ export function ContactInfoPane({
     isValidLocation(contact.lat, contact.lon)
       ? calculateDistance(config.lat, config.lon, contact.lat, contact.lon)
       : null;
+  const pathHashModeLabel = contact ? formatPathHashMode(contact.out_path_hash_mode) : null;
 
   return (
     <Sheet open={contactKey !== null} onOpenChange={(open) => !open && onClose()}>
@@ -223,6 +231,7 @@ export function ContactInfoPane({
                   />
                 )}
                 {contact.last_path_len === -1 && <InfoItem label="Routing" value="Flood" />}
+                {pathHashModeLabel && <InfoItem label="Hop Width" value={pathHashModeLabel} />}
               </div>
             </div>
 
diff --git a/frontend/src/test/contactInfoPane.test.tsx b/frontend/src/test/contactInfoPane.test.tsx
new file mode 100644
index 0000000..fadb029
--- /dev/null
+++ b/frontend/src/test/contactInfoPane.test.tsx
@@ -0,0 +1,109 @@
+import { render, screen, waitFor } from '@testing-library/react';
+import { describe, expect, it, vi, beforeEach } from 'vitest';
+
+import { ContactInfoPane } from '../components/ContactInfoPane';
+import type { Contact, ContactDetail } from '../types';
+
+const { getContactDetail } = vi.hoisted(() => ({
+  getContactDetail: vi.fn(),
+}));
+
+vi.mock('../api', () => ({
+  api: {
+    getContactDetail,
+  },
+}));
+
+vi.mock('../components/ui/sheet', () => ({
+  Sheet: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
+  SheetContent: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
+  SheetHeader: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
+  SheetTitle: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
+  SheetDescription: ({ children }: { children: React.ReactNode }) => <div>{children}</div>,
+}));
+
+vi.mock('../components/ContactAvatar', () => ({
+  ContactAvatar: () => <div data-testid="contact-avatar" />,
+}));
+
+vi.mock('../components/ui/sonner', () => ({
+  toast: {
+    error: vi.fn(),
+    success: vi.fn(),
+  },
+}));
+
+function createContact(overrides: Partial<Contact> = {}): Contact {
+  return {
+    public_key: 'AA'.repeat(32),
+    name: 'Alice',
+    type: 1,
+    flags: 0,
+    last_path: null,
+    last_path_len: 0,
+    out_path_hash_mode: 0,
+    last_advert: null,
+    lat: null,
+    lon: null,
+    last_seen: 1700000000,
+    on_radio: false,
+    last_contacted: null,
+    last_read_at: null,
+    first_seen: 1699990000,
+    ...overrides,
+  };
+}
+
+function createDetail(contact: Contact): ContactDetail {
+  return {
+    contact,
+    name_history: [],
+    dm_message_count: 0,
+    channel_message_count: 0,
+    most_active_rooms: [],
+    advert_paths: [],
+    advert_frequency: null,
+    nearest_repeaters: [],
+  };
+}
+
+const baseProps = {
+  fromChannel: false,
+  onClose: () => {},
+  contacts: [] as Contact[],
+  config: null,
+  favorites: [],
+  onToggleFavorite: () => {},
+};
+
+describe('ContactInfoPane', () => {
+  beforeEach(() => {
+    getContactDetail.mockReset();
+  });
+
+  it('shows hop width when contact has a stored path hash mode', async () => {
+    const contact = createContact({ out_path_hash_mode: 1 });
+    getContactDetail.mockResolvedValue(createDetail(contact));
+
+    render(<ContactInfoPane {...baseProps} contactKey={contact.public_key} />);
+
+    await screen.findByText('Alice');
+    await waitFor(() => {
+      expect(screen.getByText('Hop Width')).toBeInTheDocument();
+      expect(screen.getByText('2-byte IDs')).toBeInTheDocument();
+    });
+  });
+
+  it('does not show hop width for flood-routed contacts', async () => {
+    const contact = createContact({ last_path_len: -1, out_path_hash_mode: -1 });
+    getContactDetail.mockResolvedValue(createDetail(contact));
+
+    render(<ContactInfoPane {...baseProps} contactKey={contact.public_key} />);
+
+    await screen.findByText('Alice');
+    await waitFor(() => {
+      expect(screen.queryByText('Hop Width')).not.toBeInTheDocument();
+      expect(screen.getByText('Flood')).toBeInTheDocument();
+    });
+  });
+});