diff --git a/static/js/documentLibrary.js b/static/js/documentLibrary.js
index aabf7a9..da906b0 100644
--- a/static/js/documentLibrary.js
+++ b/static/js/documentLibrary.js
@@ -391,6 +391,27 @@ let _libraryArchivedView = false;   // Documents tab showing archived docs?
     }
   }
 
+  function libraryRemoveDocumentFromState(docId) {
+    const removed = _libraryDocs.find(d => String(d.id) === String(docId));
+    _libraryDocs = _libraryDocs.filter(d => String(d.id) !== String(docId));
+    _librarySelectedIds.delete(docId);
+    _libraryTotal = Math.max(0, _libraryTotal - 1);
+
+    const lang = removed && (removed.language || 'text');
+    if (lang && Object.prototype.hasOwnProperty.call(_libraryLanguages, lang)) {
+      const next = Math.max(0, Number(_libraryLanguages[lang] || 0) - 1);
+      if (next > 0) {
+        _libraryLanguages[lang] = next;
+      } else {
+        delete _libraryLanguages[lang];
+      }
+    }
+
+    libraryRenderStats();
+    libraryRenderLangChips();
+    libraryUpdateBulkCount();
+  }
+
   function libraryRenderGrid() {
     const grid = document.getElementById('doclib-grid');
     if (!grid) return;
@@ -709,8 +730,7 @@ let _libraryArchivedView = false;   // Documents tab showing archived docs?
         const res = await fetch(`${API_BASE}/api/document/${doc.id}/archive?archived=${toArchived}`, { method: 'POST', credentials: 'same-origin' });
         if (!res.ok) throw new Error('failed');
         // Drop it from the current view (it no longer belongs here) and refresh.
-        _libraryDocs = _libraryDocs.filter(d => d.id !== doc.id);
-        _libraryTotal = Math.max(0, _libraryTotal - 1);
+        libraryRemoveDocumentFromState(doc.id);
         libraryRenderGrid();
         if (uiModule) uiModule.showToast(toArchived ? 'Archived' : 'Restored');
       } catch { if (uiModule) uiModule.showError('Failed to ' + (toArchived ? 'archive' : 'restore')); }
@@ -802,8 +822,7 @@ let _libraryArchivedView = false;   // Documents tab showing archived docs?
       try {
         const res = await fetch(`${API_BASE}/api/document/${doc.id}/archive?archived=${toArchived}`, { method: 'POST', credentials: 'same-origin' });
         if (!res.ok) throw new Error('failed');
-        _libraryDocs = _libraryDocs.filter(d => d.id !== doc.id);
-        _libraryTotal = Math.max(0, _libraryTotal - 1);
+        libraryRemoveDocumentFromState(doc.id);
         libraryRenderGrid();
         if (uiModule) uiModule.showToast(toArchived ? 'Archived' : 'Restored');
       } catch { if (uiModule) uiModule.showError('Failed to ' + (toArchived ? 'archive' : 'restore')); }
@@ -1170,9 +1189,7 @@ let _libraryArchivedView = false;   // Documents tab showing archived docs?
         card.addEventListener('transitionend', () => card.remove(), { once: true });
         setTimeout(() => { if (card.parentElement) card.remove(); }, 400);
       }
-      _libraryDocs = _libraryDocs.filter(d => d.id !== docId);
-      _libraryTotal = Math.max(0, _libraryTotal - 1);
-      libraryRenderStats();
+      libraryRemoveDocumentFromState(docId);
       if (uiModule) uiModule.showToast('Document deleted');
     } catch (e) {
       if (uiModule) uiModule.showError(`Failed to delete document: ${e.message || e}`);
diff --git a/tests/test_document_library_delete_counters.py b/tests/test_document_library_delete_counters.py
new file mode 100644
index 0000000..118d7c6
--- /dev/null
+++ b/tests/test_document_library_delete_counters.py
@@ -0,0 +1,43 @@
+"""Regression for #1809: document library counters must update after delete.
+
+documentLibrary.js is a browser module with several DOM-only imports, so this
+guards the relevant wiring at the source level. A single-card delete used to
+remove the card and decrement `_libraryTotal`, but the header/chips render from
+`_libraryLanguages`, which stayed stale until a full library refetch.
+"""
+
+from pathlib import Path
+
+
+SRC = Path(__file__).resolve().parent.parent / "static/js/documentLibrary.js"
+
+
+def _src() -> str:
+    return SRC.read_text(encoding="utf-8")
+
+
+def _between(text: str, start: str, end: str) -> str:
+    begin = text.index(start)
+    finish = text.index(end, begin)
+    return text[begin:finish]
+
+
+def test_single_delete_updates_language_counters_and_chips():
+    text = _src()
+
+    helper = _between(
+        text,
+        "function libraryRemoveDocumentFromState(docId)",
+        "function libraryRenderGrid()",
+    )
+    assert "_libraryLanguages[lang]" in helper
+    assert "delete _libraryLanguages[lang]" in helper
+    assert "libraryRenderStats();" in helper
+    assert "libraryRenderLangChips();" in helper
+
+    delete_body = _between(
+        text,
+        "async function libraryDeleteSingle(docId, card)",
+        "async function libraryBulkDelete()",
+    )
+    assert "libraryRemoveDocumentFromState(docId);" in delete_body