diff --git a/public/js/calculators.js b/public/js/calculators.js
index 0d2815a..b14c735 100644
--- a/public/js/calculators.js
+++ b/public/js/calculators.js
@@ -4,6 +4,7 @@ import { calculateBMIAssessment, loadBmiLmsData } from './calculators/bmi.js';
 import { calculateBPAssessment, computeBPPercentile, loadBpReferenceData } from './calculators/bp.js';
 import { calculateBsa, calculateWeightBasedDose } from './calculators/dosing.js';
 import { loadEquipmentData, renderEquipmentResult } from './calculators/equipment.js';
+import { calculateGcs } from './calculators/gcs.js';
 import { loadGrowthLmsData } from './calculators/growth.js';
 import { initImageLightbox } from './calculators/lightbox.js';
 import { loadResusMedsData, renderResusMeds } from './calculators/resus.js';
@@ -1111,19 +1112,14 @@ initImageLightbox();
       var eye = parseInt(document.getElementById(prefix + '-eye').value) || 0;
       var verbal = parseInt(document.getElementById(prefix + '-verbal').value) || 0;
       var motor = parseInt(document.getElementById(prefix + '-motor').value) || 0;
-      var total = eye + verbal + motor;
-
-      var severity, color, bg;
-      if (total <= 8)       { severity = 'Severe (Coma)'; color = '#ef4444'; bg = '#fee2e2'; }
-      else if (total <= 12) { severity = 'Moderate'; color = '#f59e0b'; bg = '#fef3c7'; }
-      else                  { severity = 'Mild'; color = '#10b981'; bg = '#d1fae5'; }
+      var score = calculateGcs(eye, verbal, motor);
 
       var resultDiv = document.getElementById('gcs-result');
       if (resultDiv) {
         resultDiv.innerHTML =
-          '<div class="calc-result-header" style="background:' + bg + ';border-color:' + color + ';">' +
-            '<div style="font-size:24px;font-weight:700;color:' + color + ';">GCS: ' + total + '/15</div>' +
-            '<div style="font-size:14px;color:var(--g600);margin-top:4px;">' + severity + '</div>' +
+          '<div class="calc-result-header" style="background:' + score.bg + ';border-color:' + score.color + ';">' +
+            '<div style="font-size:24px;font-weight:700;color:' + score.color + ';">GCS: ' + score.total + '/15</div>' +
+            '<div style="font-size:14px;color:var(--g600);margin-top:4px;">' + score.severity + '</div>' +
           '</div>' +
           '<div class="calc-result-grid" style="margin-top:12px;">' +
             '<div class="calc-result-item"><div class="calc-result-label">Eye (E)</div><div class="calc-result-value">' + eye + '</div></div>' +
diff --git a/public/js/calculators/gcs.js b/public/js/calculators/gcs.js
new file mode 100644
index 0000000..566afe6
--- /dev/null
+++ b/public/js/calculators/gcs.js
@@ -0,0 +1,18 @@
+export function calculateGcs(eye, verbal, motor) {
+  var total = eye + verbal + motor;
+  var severity, color, bg;
+  if (total <= 8) {
+    severity = 'Severe (Coma)';
+    color = '#ef4444';
+    bg = '#fee2e2';
+  } else if (total <= 12) {
+    severity = 'Moderate';
+    color = '#f59e0b';
+    bg = '#fef3c7';
+  } else {
+    severity = 'Mild';
+    color = '#10b981';
+    bg = '#d1fae5';
+  }
+  return { total: total, severity: severity, color: color, bg: bg };
+}
diff --git a/test/calculators-data.test.js b/test/calculators-data.test.js
index f1ddf39..6182f15 100644
--- a/test/calculators-data.test.js
+++ b/test/calculators-data.test.js
@@ -419,3 +419,10 @@ test('dosing helpers preserve BSA and weight-based dose outputs', async () => {
   assert.equal(capped.volumeMl, 10);
   assert.equal(capped.capped, true);
 });
+
+test('GCS helper preserves severity thresholds', async () => {
+  const gcs = await import('../public/js/calculators/gcs.js');
+  assert.deepEqual(gcs.calculateGcs(1, 1, 1), { total: 3, severity: 'Severe (Coma)', color: '#ef4444', bg: '#fee2e2' });
+  assert.equal(gcs.calculateGcs(2, 3, 4).severity, 'Moderate');
+  assert.equal(gcs.calculateGcs(4, 5, 6).severity, 'Mild');
+});