diff --git a/src/lib/components/Header.svelte b/src/lib/components/Header.svelte
index a40ec2c..b076594 100644
--- a/src/lib/components/Header.svelte
+++ b/src/lib/components/Header.svelte
@@ -21,7 +21,7 @@
     <a href="/admin">{$t('nav.admin')}</a>
   </nav>
 
-  <button class="lang" type="button" on:click={toggleLocale} aria-label="Switch language">
+  <button class="lang" type="button" on:click={toggleLocale} aria-label={$t('lang.switch_aria')}>
     {lang === 'en' ? $t('lang.switch_to_tg') : $t('lang.switch_to_en')}
   </button>
 </header>
diff --git a/src/lib/i18n/en.json b/src/lib/i18n/en.json
index c7ad5eb..dc935b8 100644
--- a/src/lib/i18n/en.json
+++ b/src/lib/i18n/en.json
@@ -15,7 +15,8 @@
   },
   "lang": {
     "switch_to_tg": "Тоҷикӣ",
-    "switch_to_en": "English"
+    "switch_to_en": "English",
+    "switch_aria": "Switch language"
   },
   "common": {
     "save": "Save",
@@ -138,6 +139,7 @@
     "cancel_confirm": "Permanently discard this draft? All added lines will be lost.",
     "saved_total": "Total",
     "saved_thanks": "Scan the QR code below to pay.",
+    "qr_alt": "Payment QR code",
     "new_another": "Start a new sale",
     "errors": {
       "part_required": "Pick a part.",
@@ -151,6 +153,22 @@
       "line_missing": "Line not found."
     }
   },
+  "categories": {
+    "title": "Categories",
+    "intro": "Deleting a category does not delete its parts; they become uncategorized.",
+    "sort": "Sort",
+    "sort_order": "Sort order",
+    "part_count": "Parts",
+    "add": "Add a category",
+    "add_button": "Add category",
+    "delete_confirm": "Delete \"{name}\"?",
+    "delete_confirm_with_parts": "Delete \"{name}\"? {count} part(s) will become uncategorized (not deleted).",
+    "errors": {
+      "name_required": "At least one name (English or Tajik) is required.",
+      "sort_invalid": "Sort order must be a number.",
+      "id_missing": "Missing category id."
+    }
+  },
   "suppliers": {
     "title": "Suppliers",
     "name": "Name",
diff --git a/src/lib/i18n/tg.json b/src/lib/i18n/tg.json
index 861fdb7..e8d9a7b 100644
--- a/src/lib/i18n/tg.json
+++ b/src/lib/i18n/tg.json
@@ -15,7 +15,8 @@
   },
   "lang": {
     "switch_to_tg": "Тоҷикӣ",
-    "switch_to_en": "English"
+    "switch_to_en": "English",
+    "switch_aria": "Иваз кардани забон"
   },
   "common": {
     "save": "Захира",
@@ -138,6 +139,7 @@
     "cancel_confirm": "Ин лоиҳаро пурра нест мекунед? Ҳамаи сатрҳои иловашуда гум мешаванд.",
     "saved_total": "Ҳамагӣ",
     "saved_thanks": "Барои пардохт рамзи QR-ро аз поён скан кунед.",
+    "qr_alt": "Рамзи QR-и пардохт",
     "new_another": "Фурӯши нав сар кардан",
     "errors": {
       "part_required": "Қисмро интихоб кунед.",
@@ -151,6 +153,22 @@
       "line_missing": "Сатр ёфт нашуд."
     }
   },
+  "categories": {
+    "title": "Категорияҳо",
+    "intro": "Несткунии категория қисмҳои онро нест намекунад; онҳо бе категория мемонанд.",
+    "sort": "Тартиб",
+    "sort_order": "Рақами тартиб",
+    "part_count": "Қисмҳо",
+    "add": "Илова кардани категория",
+    "add_button": "Илова кардан",
+    "delete_confirm": "«{name}»-ро нест мекунед?",
+    "delete_confirm_with_parts": "«{name}»-ро нест мекунед? {count} қисм бе категория мемонанд (нест намешаванд).",
+    "errors": {
+      "name_required": "Ҳадди ақалл як ном (англисӣ ё тоҷикӣ) зарур аст.",
+      "sort_invalid": "Рақами тартиб бояд адад бошад.",
+      "id_missing": "Шиносаи категория ёфт нашуд."
+    }
+  },
   "suppliers": {
     "title": "Таъминкунандагон",
     "name": "Ном",
diff --git a/src/lib/server/categories.js b/src/lib/server/categories.js
new file mode 100644
index 0000000..277b53a
--- /dev/null
+++ b/src/lib/server/categories.js
@@ -0,0 +1,45 @@
+import { getDb } from './db.js';
+
+export function listCategoriesWithCounts() {
+  return getDb().prepare(`
+    SELECT c.*, COALESCE(COUNT(p.id), 0) AS part_count
+    FROM categories c
+    LEFT JOIN parts p ON p.category_id = c.id
+    GROUP BY c.id
+    ORDER BY c.sort_order, c.name_en
+  `).all();
+}
+
+export function getCategory(id) {
+  return getDb().prepare(`SELECT * FROM categories WHERE id = ?`).get(Number(id));
+}
+
+export function createCategory(input) {
+  const stmt = getDb().prepare(`
+    INSERT INTO categories (name_en, name_tg, sort_order)
+    VALUES (@name_en, @name_tg, @sort_order)
+  `);
+  return stmt.run(normalize(input)).lastInsertRowid;
+}
+
+export function updateCategory(id, input) {
+  getDb().prepare(`
+    UPDATE categories
+    SET name_en = @name_en, name_tg = @name_tg, sort_order = @sort_order
+    WHERE id = @id
+  `).run({ ...normalize(input), id: Number(id) });
+}
+
+// parts.category_id has ON DELETE SET NULL, so deleting a category leaves
+// its parts in place (just uncategorized).
+export function deleteCategory(id) {
+  getDb().prepare(`DELETE FROM categories WHERE id = ?`).run(Number(id));
+}
+
+function normalize(c) {
+  return {
+    name_en:    (c.name_en || '').trim(),
+    name_tg:    (c.name_tg || '').trim(),
+    sort_order: Number.isFinite(Number(c.sort_order)) ? Number(c.sort_order) : 0
+  };
+}
diff --git a/src/routes/categories/+page.server.js b/src/routes/categories/+page.server.js
new file mode 100644
index 0000000..1784fe2
--- /dev/null
+++ b/src/routes/categories/+page.server.js
@@ -0,0 +1,52 @@
+import { fail } from '@sveltejs/kit';
+import {
+  listCategoriesWithCounts,
+  createCategory,
+  updateCategory,
+  deleteCategory
+} from '$lib/server/categories.js';
+
+export function load() {
+  return { categories: listCategoriesWithCounts() };
+}
+
+function validate(data) {
+  const errors = {};
+  if (!data.name_en?.trim() && !data.name_tg?.trim()) {
+    errors.name = 'categories.errors.name_required';
+  }
+  const sort = Number(data.sort_order);
+  if (data.sort_order !== '' && data.sort_order != null && !Number.isFinite(sort)) {
+    errors.sort_order = 'categories.errors.sort_invalid';
+  }
+  return errors;
+}
+
+export const actions = {
+  create: async ({ request }) => {
+    const data = Object.fromEntries(await request.formData());
+    const errors = validate(data);
+    if (Object.keys(errors).length) return fail(400, { action: 'create', errors, values: data });
+    createCategory(data);
+    return { ok: true };
+  },
+
+  update: async ({ request }) => {
+    const data = Object.fromEntries(await request.formData());
+    const id = Number(data.id);
+    if (!id) return fail(400, { errors: { id: 'categories.errors.id_missing' } });
+    const errors = validate(data);
+    if (Object.keys(errors).length) {
+      return fail(400, { action: 'update', id, errors, values: data });
+    }
+    updateCategory(id, data);
+    return { ok: true, updatedId: id };
+  },
+
+  delete: async ({ request }) => {
+    const data = Object.fromEntries(await request.formData());
+    const id = Number(data.id);
+    if (id) deleteCategory(id);
+    return { ok: true };
+  }
+};
diff --git a/src/routes/categories/+page.svelte b/src/routes/categories/+page.svelte
new file mode 100644
index 0000000..270cd84
--- /dev/null
+++ b/src/routes/categories/+page.svelte
@@ -0,0 +1,111 @@
+<script>
+  import { enhance } from '$app/forms';
+  import { locale, t, localized } from '$lib/i18n/store.js';
+
+  export let data;
+  export let form;
+  $: lang = $locale;
+  $: ({ categories } = data);
+
+  $: createErrors = form?.action === 'create' ? (form.errors ?? {}) : {};
+  $: createValues = form?.action === 'create' ? (form.values ?? {}) : {};
+
+  function rowErrors(id) {
+    return form?.action === 'update' && form.id === id ? (form.errors ?? {}) : {};
+  }
+
+  function confirmDelete(cat) {
+    const name = localized(cat, 'name', lang) || cat.name_en || cat.name_tg;
+    const template = cat.part_count > 0
+      ? $t('categories.delete_confirm_with_parts')
+      : $t('categories.delete_confirm');
+    const msg = template.replace('{name}', name).replace('{count}', cat.part_count);
+    return (e) => { if (!confirm(msg)) e.preventDefault(); };
+  }
+</script>
+
+<h1>{$t('categories.title')}</h1>
+
+<p class="muted">{$t('categories.intro')}</p>
+
+<!--
+  The update and delete forms live outside the table because a <form> is not
+  permitted as a child of <tr>. Inputs inside the rows associate via the
+  HTML `form` attribute.
+-->
+{#each categories as c (c.id)}
+  <form method="POST" action="?/update" use:enhance id={`row-${c.id}`} hidden>
+    <input type="hidden" name="id" value={c.id} />
+  </form>
+  <form method="POST" action="?/delete" use:enhance id={`del-${c.id}`}
+        on:submit={confirmDelete(c)} hidden>
+    <input type="hidden" name="id" value={c.id} />
+  </form>
+{/each}
+
+<table>
+  <thead>
+    <tr>
+      <th class="num">{$t('categories.sort')}</th>
+      <th>{$t('parts.name_en')}</th>
+      <th>{$t('parts.name_tg')}</th>
+      <th class="num">{$t('categories.part_count')}</th>
+      <th></th>
+    </tr>
+  </thead>
+  <tbody>
+    {#each categories as c (c.id)}
+      {@const errs = rowErrors(c.id)}
+      <tr>
+        <td class="num">
+          <input form={`row-${c.id}`} name="sort_order" type="number" step="1"
+                 value={c.sort_order} class="sort-input" />
+        </td>
+        <td>
+          <input form={`row-${c.id}`} name="name_en" value={c.name_en ?? ''} />
+        </td>
+        <td>
+          <input form={`row-${c.id}`} name="name_tg" value={c.name_tg ?? ''} />
+        </td>
+        <td class="num">{c.part_count}</td>
+        <td class="actions">
+          <button form={`row-${c.id}`} type="submit">{$t('common.save')}</button>
+          <button form={`del-${c.id}`} type="submit" class="danger">{$t('common.delete')}</button>
+          {#if errs.name}<div class="field-error">{$t(errs.name)}</div>{/if}
+          {#if errs.sort_order}<div class="field-error">{$t(errs.sort_order)}</div>{/if}
+        </td>
+      </tr>
+    {/each}
+  </tbody>
+</table>
+
+<h2>{$t('categories.add')}</h2>
+<form class="stack" method="POST" action="?/create" use:enhance>
+  <div class="row">
+    <label>
+      {$t('parts.name_en')}
+      <input name="name_en" value={createValues.name_en ?? ''} />
+    </label>
+    <label>
+      {$t('parts.name_tg')}
+      <input name="name_tg" value={createValues.name_tg ?? ''} />
+    </label>
+  </div>
+  <label>
+    {$t('categories.sort_order')}
+    <input name="sort_order" type="number" step="1" value={createValues.sort_order ?? '0'} />
+  </label>
+  {#if createErrors.name}<span class="field-error">{$t(createErrors.name)}</span>{/if}
+  {#if createErrors.sort_order}<span class="field-error">{$t(createErrors.sort_order)}</span>{/if}
+  <div>
+    <button type="submit">{$t('categories.add_button')}</button>
+  </div>
+</form>
+
+<style>
+  .actions { display: flex; gap: 0.4rem; align-items: center; flex-wrap: wrap; }
+  .sort-input { width: 4.5rem; text-align: right; }
+  .field-error { color: #8a1f1b; font-size: 0.8rem; width: 100%; }
+  td input { width: 100%; }
+  td.num input { width: auto; }
+</style>
diff --git a/src/routes/invoices/[id]/+page.svelte b/src/routes/invoices/[id]/+page.svelte
index 3c8df12..13ac0ea 100644
--- a/src/routes/invoices/[id]/+page.svelte
+++ b/src/routes/invoices/[id]/+page.svelte
@@ -52,7 +52,7 @@
 
   <section class="pay">
     <p class="muted">{$t('invoices.saved_thanks')}</p>
-    <img src="/payment-qr.png" alt="Payment QR code" class="qr" />
+    <img src="/payment-qr.png" alt={$t('invoices.qr_alt')} class="qr" />
   </section>
 </article>