diff --git a/public/js/calculators.js b/public/js/calculators.js
index 2ece546..6330988 100644
--- a/public/js/calculators.js
+++ b/public/js/calculators.js
@@ -1571,15 +1571,23 @@
       var bc = document.getElementById('bili-chart-container'); if (bc) bc.classList.add('hidden');
     });
 
-    // Bhutani nomogram zones (approximate hour-specific TSB boundaries)
-    // High-risk zone: >= 95th percentile
-    // High-intermediate: 75th-95th
-    // Low-intermediate: 40th-75th
-    // Low-risk: < 40th
+    // Bhutani 1999 hour-specific risk nomogram — 40th / 75th / 95th
+    // percentile TSB boundaries read from the Stanford Medicine Newborn
+    // Nursery reproduction of the original Figure 2 (Bhutani VK et al.,
+    // Pediatrics 1999;103(1):6-14):
+    //   https://med.stanford.edu/newborns/professional-education/jaundice-and-phototherapy/bhutani-nomogram.html
+    // Uncertainty: ±0.3 mg/dL — source is a rendered graph, not a table.
+    // For phototherapy / exchange decisions use the AAP 2022 tab (verified).
+    //
+    // Zone semantics:
+    //   High-risk:         >= 95th percentile
+    //   High-intermediate: 75th-95th
+    //   Low-intermediate:  40th-75th
+    //   Low-risk:          < 40th
     var bhutaniZones = {
-      p95: { 24:8.0, 36:10.5, 48:12.5, 60:14.0, 72:15.0, 84:15.5, 96:16.5, 108:17.5, 120:18.0, 132:18.5, 144:19.0 },
-      p75: { 24:6.0, 36:8.5, 48:10.5, 60:12.0, 72:13.0, 84:13.5, 96:14.0, 108:14.5, 120:15.0, 132:15.5, 144:15.5 },
-      p40: { 24:4.5, 36:6.5, 48:8.5, 60:10.0, 72:11.0, 84:11.5, 96:12.0, 108:12.0, 120:12.5, 132:12.5, 144:12.5 }
+      p95: { 24:8.0,  36:11.5, 48:13.0, 60:14.0, 72:15.0, 84:15.5, 96:16.0, 108:16.5, 120:17.0, 132:17.2, 144:17.5 },
+      p75: { 24:6.5,  36:9.5,  48:11.0, 60:12.0, 72:13.0, 84:13.5, 96:14.0, 108:14.0, 120:14.5, 132:14.5, 144:14.5 },
+      p40: { 24:4.5,  36:7.0,  48:8.5,  60:9.5,  72:10.5, 84:11.0, 96:11.5, 108:12.0, 120:12.0, 132:12.0, 144:12.0 }
     };
 
     document.getElementById('btn-calc-bhutani').addEventListener('click', function() {
@@ -1609,7 +1617,7 @@
           '<div class="calc-result-item"><div class="calc-result-label">75th %ile</div><div class="calc-result-value" style="font-size:16px;color:#f97316;">' + p75.toFixed(1) + '</div><div class="calc-result-sub">High-intermediate</div></div>' +
           '<div class="calc-result-item"><div class="calc-result-label">40th %ile</div><div class="calc-result-value" style="font-size:16px;color:#f59e0b;">' + p40.toFixed(1) + '</div><div class="calc-result-sub">Low-intermediate</div></div>' +
         '</div>' +
-        '<p style="font-size:11px;color:var(--g400);margin:12px 0 0;">Bhutani hour-specific nomogram for infants &ge; 35 weeks GA. Bhutani et al., Pediatrics 1999.</p>';
+        '<p style="font-size:11px;color:var(--g400);margin:12px 0 0;">Bhutani hour-specific nomogram for infants &ge; 35 weeks GA. Values approximated from the Stanford Medicine Bhutani nomogram (reproduces Bhutani et al., Pediatrics 1999). Uncertainty &plusmn;0.3 mg/dL &mdash; use the AAP 2022 tab for phototherapy decisions.</p>';
 
       // Chart: Bhutani zone curves with patient
       renderBiliChart(hours, tsb, [