diff --git a/public/js/calculators.js b/public/js/calculators.js
index 64e839d..133b4d7 100644
--- a/public/js/calculators.js
+++ b/public/js/calculators.js
@@ -736,7 +736,7 @@
       }
       // Convert Z to percentile using standard normal CDF approximation
       var p = normalCDF(z);
-      return { z: z, percentile: Math.round(p * 1000) / 10 };
+      return { z: z, percentile: Math.round(p * 10000) / 100 };
     }
 
     function normalCDF(z) {
@@ -1115,7 +1115,7 @@
     }
 
     function renderGrowthResult(label, value, unit, z, percentile) {
-      var pctl = Math.round(percentile * 10) / 10;
+      var pctl = (Math.round(percentile * 100) / 100).toFixed(2);
       var cl;
       if (pctl >= 95 || pctl <= 5) cl = { color: '#f59e0b', bg: '#fef3c7', text: pctl <= 5 ? 'Below 5th percentile' : 'Above 95th percentile' };
       else if (pctl >= 85 || pctl <= 15) cl = { color: '#f97316', bg: '#ffedd5', text: pctl + 'th percentile' };
@@ -1207,7 +1207,7 @@
           // Calculate what percentile the MPH corresponds to using adult height LMS (~18y = 216mo)
           var adultLms = interpolateLMS(cdcLfaLMS[sex], 216);
           var mphZ = calcZFromLMS(mph.target, adultLms.L, adultLms.M, adultLms.S);
-          var mphPctile = Math.round(normalCDF(mphZ) * 1000) / 10;
+          var mphPctile = (Math.round(normalCDF(mphZ) * 10000) / 100).toFixed(2);
           resultDiv.innerHTML += '<div style="margin-top:8px;padding:8px 12px;background:#ede9fe;border-radius:6px;font-size:13px;color:#6d28d9;"><strong>Mid-Parental Height:</strong> ' + mph.target.toFixed(1) + ' cm (' + mphPctile + 'th percentile) &mdash; target range: ' + mph.low.toFixed(1) + ' - ' + mph.high.toFixed(1) + ' cm</div>';
           // MPH coordinates: use years if age > 24mo
           var mphX1 = age > 24 ? 17 : 204;