diff --git a/templates/index.html b/templates/index.html
index 3adc216..3363890 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -356,6 +356,7 @@ <h2 style="margin-top:20px;">5. Detail &amp; Output</h2>
     cb.id = 'part_' + shown;
     cb.addEventListener('change', () => {
       if (cb.checked) excludedParts.delete(name); else excludedParts.add(name);
+      updatePartCount();
     });
     const label = document.createElement('label');
     label.setAttribute('for', cb.id);
@@ -364,6 +365,14 @@ <h2 style="margin-top:20px;">5. Detail &amp; Output</h2>
     row.appendChild(label);
     box.appendChild(row);
   });
+  updatePartCount(shown);
+}
+
+function updatePartCount(shown) {
+  if (shown === undefined) {
+    const filterText = document.getElementById('part_filter').value.toLowerCase();
+    shown = allPartNames.filter(n => !filterText || n.toLowerCase().includes(filterText)).length;
+  }
   document.getElementById('part_count').textContent =
     shown + ' of ' + allPartNames.length + ' shown, ' +
     (allPartNames.length - excludedParts.size) + ' included';