diff --git a/frontend/src/lib/components/ChapterPagesEditor.svelte b/frontend/src/lib/components/ChapterPagesEditor.svelte
index 57e0b91..f35292f 100644
--- a/frontend/src/lib/components/ChapterPagesEditor.svelte
+++ b/frontend/src/lib/components/ChapterPagesEditor.svelte
@@ -17,6 +17,7 @@
     import { onDestroy } from 'svelte';
     import { formatBytes, validateImageFile } from '$lib/upload-validation';
     import Modal from './Modal.svelte';
+    import IconButton from '$lib/components/IconButton.svelte';
     import ArrowUp from '@lucide/svelte/icons/arrow-up';
     import ArrowDown from '@lucide/svelte/icons/arrow-down';
     import Trash2 from '@lucide/svelte/icons/trash-2';
@@ -145,36 +146,31 @@
                         from {p.file.name} · {formatBytes(p.file.size)}
                     </span>
                 </div>
-                <button
-                    class="icon-btn"
-                    type="button"
+                <IconButton
                     onclick={() => movePage(p.id, -1)}
                     disabled={i === 0}
                     aria-label="Move {pageLabel(i)} up"
                     title="Move up"
                 >
                     <ArrowUp size={16} aria-hidden="true" />
-                </button>
-                <button
-                    class="icon-btn"
-                    type="button"
+                </IconButton>
+                <IconButton
                     onclick={() => movePage(p.id, 1)}
                     disabled={i === pages.length - 1}
                     aria-label="Move {pageLabel(i)} down"
                     title="Move down"
                 >
                     <ArrowDown size={16} aria-hidden="true" />
-                </button>
-                <button
-                    class="icon-btn danger"
-                    type="button"
+                </IconButton>
+                <IconButton
+                    variant="danger"
                     onclick={() => removePage(p.id)}
                     aria-label="Remove {pageLabel(i)}"
                     title="Remove page"
                     data-testid="{testidPrefix}-remove"
                 >
                     <Trash2 size={16} aria-hidden="true" />
-                </button>
+                </IconButton>
                 {#if p.error}
                     <span class="field-error" role="alert">{p.error}</span>
                 {/if}
@@ -297,28 +293,6 @@
         white-space: nowrap;
     }
 
-    .icon-btn {
-        display: inline-flex;
-        align-items: center;
-        justify-content: center;
-        width: 32px;
-        height: 32px;
-        padding: 0;
-        background: transparent;
-        color: var(--text-muted);
-        border: 1px solid transparent;
-        border-radius: var(--radius-sm);
-    }
-
-    .icon-btn:hover:not(:disabled) {
-        background: var(--surface-elevated);
-        color: var(--text);
-    }
-
-    .icon-btn.danger:hover:not(:disabled) {
-        color: var(--danger);
-    }
-
     .field-error {
         grid-column: 1 / -1;
         color: var(--danger);
diff --git a/frontend/src/lib/components/IconButton.svelte b/frontend/src/lib/components/IconButton.svelte
new file mode 100644
index 0000000..08a1852
--- /dev/null
+++ b/frontend/src/lib/components/IconButton.svelte
@@ -0,0 +1,80 @@
+<script lang="ts">
+    import type { Snippet } from 'svelte';
+    import type { HTMLButtonAttributes } from 'svelte/elements';
+
+    // Shared square icon button — extracted from the near-identical
+    // `.icon-btn` copies across the app so the size, hover, and variant
+    // treatment live in one place. Callers pass the lucide icon as the child
+    // and any button attributes (onclick, disabled, aria-label, title,
+    // data-testid) straight through. `size`/`radius` cover the two larger
+    // header/search buttons without forcing the 32px default everywhere.
+    type Variant = 'plain' | 'primary' | 'danger';
+
+    let {
+        variant = 'plain',
+        size = 32,
+        radius = 'sm',
+        children,
+        ...rest
+    }: {
+        variant?: Variant;
+        size?: number;
+        radius?: 'sm' | 'md';
+        children: Snippet;
+    } & HTMLButtonAttributes = $props();
+</script>
+
+<!-- `type="button"` precedes the spread so a caller can still override it
+     (e.g. a submit button) while the default never submits a form. -->
+<button
+    type="button"
+    class="icon-btn {variant} radius-{radius}"
+    style:--ib-size="{size}px"
+    {...rest}
+>
+    {@render children()}
+</button>
+
+<style>
+    .icon-btn {
+        display: inline-flex;
+        align-items: center;
+        justify-content: center;
+        width: var(--ib-size, 32px);
+        height: var(--ib-size, 32px);
+        padding: 0;
+        background: transparent;
+        color: var(--text-muted);
+        border: 1px solid transparent;
+        cursor: pointer;
+    }
+
+    .radius-sm {
+        border-radius: var(--radius-sm);
+    }
+
+    .radius-md {
+        border-radius: var(--radius-md);
+    }
+
+    .icon-btn:hover:not(:disabled) {
+        background: var(--surface-elevated);
+        color: var(--text);
+    }
+
+    .icon-btn.primary {
+        background: var(--primary);
+        color: var(--primary-contrast);
+        border-color: var(--primary);
+    }
+
+    .icon-btn.primary:hover:not(:disabled) {
+        background: var(--primary-hover);
+        border-color: var(--primary-hover);
+    }
+
+    .icon-btn.danger:hover:not(:disabled) {
+        color: var(--danger);
+        background: var(--surface-elevated);
+    }
+</style>
diff --git a/frontend/src/lib/components/IconButton.svelte.test.ts b/frontend/src/lib/components/IconButton.svelte.test.ts
new file mode 100644
index 0000000..46e1769
--- /dev/null
+++ b/frontend/src/lib/components/IconButton.svelte.test.ts
@@ -0,0 +1,79 @@
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { render, screen, cleanup, fireEvent } from '@testing-library/svelte';
+import { createRawSnippet } from 'svelte';
+import IconButton from './IconButton.svelte';
+
+afterEach(() => cleanup());
+
+// A stand-in for the lucide icon callers pass as the child.
+const icon = createRawSnippet(() => ({
+    render: () => `<svg data-testid="glyph"></svg>`
+}));
+
+describe('IconButton', () => {
+    it('renders a button containing the icon child', () => {
+        render(IconButton, { props: { children: icon } });
+        const btn = screen.getByRole('button');
+        expect(btn.querySelector('[data-testid="glyph"]')).toBeTruthy();
+    });
+
+    it('defaults to type=button so it never submits a surrounding form by accident', () => {
+        render(IconButton, { props: { children: icon } });
+        expect(screen.getByRole('button').getAttribute('type')).toBe('button');
+    });
+
+    it('lets a caller override the type (e.g. submit)', () => {
+        render(IconButton, { props: { type: 'submit', children: icon } });
+        expect(screen.getByRole('button').getAttribute('type')).toBe('submit');
+    });
+
+    it('applies the variant as a class (plain by default)', () => {
+        const { container } = render(IconButton, { props: { children: icon } });
+        expect(container.querySelector('button.icon-btn.plain')).toBeTruthy();
+        cleanup();
+        const { container: c2 } = render(IconButton, {
+            props: { variant: 'danger', children: icon }
+        });
+        expect(c2.querySelector('button.icon-btn.danger')).toBeTruthy();
+    });
+
+    it('defaults to a 32px square with the small radius', () => {
+        const { container } = render(IconButton, { props: { children: icon } });
+        const btn = container.querySelector('button.icon-btn') as HTMLButtonElement;
+        expect(btn.classList.contains('radius-sm')).toBe(true);
+        expect(btn.style.getPropertyValue('--ib-size')).toBe('32px');
+    });
+
+    it('honours an explicit size and radius (the larger header/search buttons)', () => {
+        const { container } = render(IconButton, {
+            props: { size: 36, radius: 'md', children: icon }
+        });
+        const btn = container.querySelector('button.icon-btn') as HTMLButtonElement;
+        expect(btn.style.getPropertyValue('--ib-size')).toBe('36px');
+        expect(btn.classList.contains('radius-md')).toBe(true);
+        expect(btn.classList.contains('radius-sm')).toBe(false);
+    });
+
+    it('forwards onclick', async () => {
+        const onclick = vi.fn();
+        render(IconButton, { props: { onclick, children: icon } });
+        await fireEvent.click(screen.getByRole('button'));
+        expect(onclick).toHaveBeenCalledOnce();
+    });
+
+    it('forwards arbitrary button attributes (aria-label, title, disabled, data-testid)', () => {
+        render(IconButton, {
+            props: {
+                'aria-label': 'Delete collection',
+                title: 'Delete',
+                disabled: true,
+                'data-testid': 'collection-delete',
+                children: icon
+            }
+        });
+        const btn = screen.getByTestId('collection-delete');
+        expect(btn.getAttribute('aria-label')).toBe('Delete collection');
+        expect(btn.getAttribute('title')).toBe('Delete');
+        expect((btn as HTMLButtonElement).disabled).toBe(true);
+    });
+});
diff --git a/frontend/src/routes/+layout.svelte b/frontend/src/routes/+layout.svelte
index c8d4095..c621b41 100644
--- a/frontend/src/routes/+layout.svelte
+++ b/frontend/src/routes/+layout.svelte
@@ -9,6 +9,7 @@
     import { theme } from '$lib/theme.svelte';
     import AppBar from '$lib/components/AppBar.svelte';
     import BottomNav, { type BottomNavTab } from '$lib/components/BottomNav.svelte';
+    import IconButton from '$lib/components/IconButton.svelte';
     import Upload from '@lucide/svelte/icons/upload';
     import UserCircle from '@lucide/svelte/icons/user-circle';
     import Bookmark from '@lucide/svelte/icons/bookmark';
@@ -232,9 +233,9 @@
             <span data-testid="session-loading" aria-busy="true">…</span>
         {:else if session.user}
             <span class="username" data-testid="session-user">{session.user.username}</span>
-            <button
-                class="icon-btn"
-                type="button"
+            <IconButton
+                size={36}
+                radius="md"
                 onclick={handleLogout}
                 disabled={loggingOut}
                 aria-label="Logout"
@@ -245,7 +246,7 @@
                 {:else}
                     <LogOut size={18} aria-hidden="true" />
                 {/if}
-            </button>
+            </IconButton>
         {:else}
             <a class="text-link" href="/login" data-testid="nav-login">Login</a>
             {#if authConfig.self_register_enabled}
@@ -348,24 +349,6 @@
         padding: 0 var(--space-2);
     }
 
-    .icon-btn {
-        display: inline-flex;
-        align-items: center;
-        justify-content: center;
-        width: 36px;
-        height: 36px;
-        padding: 0;
-        background: transparent;
-        color: var(--text-muted);
-        border: 1px solid transparent;
-        border-radius: var(--radius-md);
-    }
-
-    .icon-btn:hover:not(:disabled) {
-        background: var(--surface-elevated);
-        color: var(--text);
-    }
-
     .logging-out {
         font-size: var(--font-base);
         line-height: 1;
diff --git a/frontend/src/routes/+page.svelte b/frontend/src/routes/+page.svelte
index 683dea9..b6b8209 100644
--- a/frontend/src/routes/+page.svelte
+++ b/frontend/src/routes/+page.svelte
@@ -27,6 +27,7 @@
     import Pager from '$lib/components/Pager.svelte';
     import SegmentedControl from '$lib/components/SegmentedControl.svelte';
     import Sheet from '$lib/components/Sheet.svelte';
+    import IconButton from '$lib/components/IconButton.svelte';
     import Search from '@lucide/svelte/icons/search';
     import SlidersHorizontal from '@lucide/svelte/icons/sliders-horizontal';
     import ArrowUpDown from '@lucide/svelte/icons/arrow-up-down';
@@ -467,9 +468,16 @@
             placeholder="Search by title or author"
             data-testid="search-input"
         />
-        <button class="icon-btn primary" type="submit" aria-label="Search" title="Search">
+        <IconButton
+            variant="primary"
+            size={36}
+            radius="md"
+            type="submit"
+            aria-label="Search"
+            title="Search"
+        >
             <Search size={18} aria-hidden="true" />
-        </button>
+        </IconButton>
         <button
             type="button"
             class="filters-toggle"
@@ -923,26 +931,6 @@
         border-color: var(--primary-hover);
     }
 
-    .icon-btn {
-        display: inline-flex;
-        align-items: center;
-        justify-content: center;
-        width: 36px;
-        height: 36px;
-        padding: 0;
-    }
-
-    .icon-btn.primary {
-        background: var(--primary);
-        color: var(--primary-contrast);
-        border: 1px solid var(--primary);
-    }
-
-    .icon-btn.primary:hover:not(:disabled) {
-        background: var(--primary-hover);
-        border-color: var(--primary-hover);
-    }
-
     .status {
         color: var(--text-muted);
     }
diff --git a/frontend/src/routes/collections/[id]/+page.svelte b/frontend/src/routes/collections/[id]/+page.svelte
index 4c8585a..a8f58f7 100644
--- a/frontend/src/routes/collections/[id]/+page.svelte
+++ b/frontend/src/routes/collections/[id]/+page.svelte
@@ -12,6 +12,7 @@
     import type { Manga } from '$lib/api/client';
     import { fileUrl } from '$lib/api/client';
     import MangaCard from '$lib/components/MangaCard.svelte';
+    import IconButton from '$lib/components/IconButton.svelte';
     import ArrowLeft from '@lucide/svelte/icons/arrow-left';
     import Pencil from '@lucide/svelte/icons/pencil';
     import Check from '@lucide/svelte/icons/check';
@@ -148,26 +149,23 @@
     {:else}
         <div class="title-row">
             <h1 data-testid="collection-name">{collection.name}</h1>
-            <button
-                type="button"
-                class="icon-btn"
+            <IconButton
                 onclick={startEdit}
                 aria-label="Edit collection"
                 title="Edit"
                 data-testid="collection-edit-open"
             >
                 <Pencil size={16} aria-hidden="true" />
-            </button>
-            <button
-                type="button"
-                class="icon-btn danger"
+            </IconButton>
+            <IconButton
+                variant="danger"
                 onclick={onDeleteCollection}
                 aria-label="Delete collection"
                 title="Delete"
                 data-testid="collection-delete"
             >
                 <Trash2 size={16} aria-hidden="true" />
-            </button>
+            </IconButton>
         </div>
         {#if collection.description}
             <p class="description" data-testid="collection-description">
@@ -418,26 +416,4 @@
             height: 32px;
         }
     }
-
-    .icon-btn {
-        display: inline-flex;
-        align-items: center;
-        justify-content: center;
-        width: 32px;
-        height: 32px;
-        padding: 0;
-        background: transparent;
-        color: var(--text-muted);
-        border: 1px solid transparent;
-        border-radius: var(--radius-sm);
-    }
-
-    .icon-btn:hover {
-        background: var(--surface-elevated);
-        color: var(--text);
-    }
-
-    .icon-btn.danger:hover {
-        color: var(--danger);
-    }
 </style>
diff --git a/frontend/src/routes/manga/[id]/edit/+page.svelte b/frontend/src/routes/manga/[id]/edit/+page.svelte
index b6b801c..19ce1b3 100644
--- a/frontend/src/routes/manga/[id]/edit/+page.svelte
+++ b/frontend/src/routes/manga/[id]/edit/+page.svelte
@@ -10,6 +10,7 @@
     import { session } from '$lib/session.svelte';
     import { formatBytes, validateImageFile } from '$lib/upload-validation';
     import Chip from '$lib/components/Chip.svelte';
+    import IconButton from '$lib/components/IconButton.svelte';
     import Plus from '@lucide/svelte/icons/plus';
     import Trash2 from '@lucide/svelte/icons/trash-2';
 
@@ -190,16 +191,15 @@
                         maxlength="200"
                         data-testid="manga-author-input"
                     />
-                    <button
-                        type="button"
-                        class="icon-btn primary"
+                    <IconButton
+                        variant="primary"
                         onclick={addAuthor}
                         disabled={!authorDraft.trim()}
                         aria-label="Add author"
                         title="Add author"
                     >
                         <Plus size={16} aria-hidden="true" />
-                    </button>
+                    </IconButton>
                 </div>
             </div>
 
@@ -240,16 +240,15 @@
                         maxlength="200"
                         data-testid="manga-alt-input"
                     />
-                    <button
-                        type="button"
-                        class="icon-btn primary"
+                    <IconButton
+                        variant="primary"
                         onclick={addAltTitle}
                         disabled={!altTitleDraft.trim()}
                         aria-label="Add alternative title"
                         title="Add alternative title"
                     >
                         <Plus size={16} aria-hidden="true" />
-                    </button>
+                    </IconButton>
                 </div>
             </div>
 
@@ -270,16 +269,15 @@
                             src={fileUrl(currentCoverPath)}
                             alt="Current cover"
                         />
-                        <button
-                            type="button"
-                            class="icon-btn danger"
+                        <IconButton
+                            variant="danger"
                             onclick={markCoverForRemoval}
                             aria-label="Remove cover"
                             title="Remove cover"
                             data-testid="cover-remove"
                         >
                             <Trash2 size={16} aria-hidden="true" />
-                        </button>
+                        </IconButton>
                     </div>
                 {:else if pendingCoverRemoval}
                     <p class="hint" data-testid="cover-pending-removal">
@@ -419,39 +417,6 @@
         cursor: pointer;
     }
 
-    .icon-btn {
-        display: inline-flex;
-        align-items: center;
-        justify-content: center;
-        width: 32px;
-        height: 32px;
-        padding: 0;
-        background: transparent;
-        color: var(--text-muted);
-        border: 1px solid transparent;
-        border-radius: var(--radius-sm);
-    }
-
-    .icon-btn:hover:not(:disabled) {
-        background: var(--surface-elevated);
-        color: var(--text);
-    }
-
-    .icon-btn.primary {
-        background: var(--primary);
-        color: var(--primary-contrast);
-        border-color: var(--primary);
-    }
-
-    .icon-btn.primary:hover:not(:disabled) {
-        background: var(--primary-hover);
-        border-color: var(--primary-hover);
-    }
-
-    .icon-btn.danger:hover:not(:disabled) {
-        color: var(--danger);
-    }
-
     .cover-preview {
         display: flex;
         align-items: flex-start;
diff --git a/frontend/src/routes/upload/+page.svelte b/frontend/src/routes/upload/+page.svelte
index e04ac3e..a5326c0 100644
--- a/frontend/src/routes/upload/+page.svelte
+++ b/frontend/src/routes/upload/+page.svelte
@@ -9,6 +9,7 @@
     import ChapterPagesEditor, {
         type PendingPage
     } from '$lib/components/ChapterPagesEditor.svelte';
+    import IconButton from '$lib/components/IconButton.svelte';
     import Plus from '@lucide/svelte/icons/plus';
     import Trash2 from '@lucide/svelte/icons/trash-2';
 
@@ -236,16 +237,15 @@
                         maxlength="200"
                         data-testid="manga-author-input"
                     />
-                    <button
-                        type="button"
-                        class="icon-btn primary"
+                    <IconButton
+                        variant="primary"
                         onclick={addAuthor}
                         disabled={!authorDraft.trim()}
                         aria-label="Add author"
                         title="Add author"
                     >
                         <Plus size={16} aria-hidden="true" />
-                    </button>
+                    </IconButton>
                 </div>
             </div>
 
@@ -286,16 +286,15 @@
                         maxlength="200"
                         data-testid="manga-alt-input"
                     />
-                    <button
-                        type="button"
-                        class="icon-btn primary"
+                    <IconButton
+                        variant="primary"
                         onclick={addAltTitle}
                         disabled={!altTitleDraft.trim()}
                         aria-label="Add alternative title"
                         title="Add alternative title"
                     >
                         <Plus size={16} aria-hidden="true" />
-                    </button>
+                    </IconButton>
                 </div>
             </div>
 
@@ -378,16 +377,15 @@
                                         Failed
                                     {/if}
                                 </span>
-                                <button
-                                    type="button"
-                                    class="icon-btn danger"
+                                <IconButton
+                                    variant="danger"
                                     onclick={() => removeChapter(c.id)}
                                     aria-label="Remove chapter"
                                     title="Remove chapter"
                                     data-testid="staged-chapter-remove"
                                 >
                                     <Trash2 size={16} aria-hidden="true" />
-                                </button>
+                                </IconButton>
                             </div>
                             {#if c.error}
                                 <p class="field-error" role="alert">{c.error}</p>
@@ -513,39 +511,6 @@
         cursor: pointer;
     }
 
-    .icon-btn {
-        display: inline-flex;
-        align-items: center;
-        justify-content: center;
-        width: 32px;
-        height: 32px;
-        padding: 0;
-        background: transparent;
-        color: var(--text-muted);
-        border: 1px solid transparent;
-        border-radius: var(--radius-sm);
-    }
-
-    .icon-btn:hover:not(:disabled) {
-        background: var(--surface-elevated);
-        color: var(--text);
-    }
-
-    .icon-btn.primary {
-        background: var(--primary);
-        color: var(--primary-contrast);
-        border-color: var(--primary);
-    }
-
-    .icon-btn.primary:hover:not(:disabled) {
-        background: var(--primary-hover);
-        border-color: var(--primary-hover);
-    }
-
-    .icon-btn.danger:hover:not(:disabled) {
-        color: var(--danger);
-    }
-
     .chapters-header {
         display: flex;
         align-items: center;