diff --git a/public/js/calculators.js b/public/js/calculators.js
index b14c735..01b28b9 100644
--- a/public/js/calculators.js
+++ b/public/js/calculators.js
@@ -5,7 +5,7 @@ import { calculateBPAssessment, computeBPPercentile, loadBpReferenceData } from
 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 { calcMidParentalHeight, calcZFromLMS, interpolateLMS, loadGrowthLmsData, normalCDF, renderGrowthResult, valueFromLMS } from './calculators/growth.js';
 import { initImageLightbox } from './calculators/lightbox.js';
 import { loadResusMedsData, renderResusMeds } from './calculators/resus.js';
 import { loadVitalsData, renderVitalsResult } from './calculators/vitals.js';
@@ -194,25 +194,10 @@ initImageLightbox();
 
     // CDC BMI-for-age LMS values load from /data/calculators/bmi-lms.json.
 
-    function normalCDF(z) {
-      var a1=0.254829592, a2=-0.284496736, a3=1.421413741, a4=-1.453152027, a5=1.061405429, p=0.3275911;
-      var sign = z < 0 ? -1 : 1;
-      z = Math.abs(z) / Math.sqrt(2);
-      var t = 1 / (1 + p * z);
-      var y = 1 - (((((a5*t+a4)*t)+a3)*t+a2)*t+a1)*t*Math.exp(-z*z);
-      return 0.5 * (1 + sign * y);
-    }
-
     // ═══════════════════════════════════════════════════════════
     // CHART.JS GROWTH CURVE RENDERING
     // ═══════════════════════════════════════════════════════════
 
-    // Inverse LMS: given Z-score, return measurement value
-    function valueFromLMS(L, M, S, z) {
-      if (Math.abs(L) < 0.001) return M * Math.exp(S * z);
-      return M * Math.pow(1 + L * S * z, 1 / L);
-    }
-
     // 7-line reference set: 3, 10, 25, 50, 75, 90, 97.
     // Drops 5th and 95th (they crowded the 3rd/10th and 90th/97th labels
     // on mobile without adding clinical value — 3rd/97th are the
@@ -431,13 +416,6 @@ initImageLightbox();
       });
     }
 
-    // Mid-parental height calculation
-    function calcMidParentalHeight(motherHt, fatherHt, sex) {
-      if (!motherHt || !fatherHt) return null;
-      var mph = sex === 'male' ? (motherHt + fatherHt + 13) / 2 : (motherHt + fatherHt - 13) / 2;
-      return { target: mph, low: mph - 8.5, high: mph + 8.5 };
-    }
-
     var BMI_LMS = null;
     loadBmiLmsData()
       .then(function(data) { BMI_LMS = data; })
@@ -620,42 +598,6 @@ initImageLightbox();
       });
     });
 
-    function interpolateLMS(lmsTable, val) {
-      var keys = Object.keys(lmsTable).map(Number).sort(function(a,b){return a-b;});
-      if (val <= keys[0]) return lmsTable[keys[0]];
-      if (val >= keys[keys.length-1]) return lmsTable[keys[keys.length-1]];
-      for (var i = 0; i < keys.length - 1; i++) {
-        if (val >= keys[i] && val <= keys[i+1]) {
-          var t = (val - keys[i]) / (keys[i+1] - keys[i]);
-          var a = lmsTable[keys[i]], b = lmsTable[keys[i+1]];
-          return { L: a.L + t*(b.L-a.L), M: a.M + t*(b.M-a.M), S: a.S + t*(b.S-a.S) };
-        }
-      }
-      return lmsTable[keys[0]];
-    }
-
-    function calcZFromLMS(value, L, M, S) {
-      if (Math.abs(L) < 0.001) return Math.log(value / M) / S;
-      return (Math.pow(value / M, L) - 1) / (L * S);
-    }
-
-    function renderGrowthResult(label, value, unit, z, percentile) {
-      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' };
-      else cl = { color: '#10b981', bg: '#d1fae5', text: pctl + 'th percentile' };
-
-      return '<div class="calc-result-header" style="background:' + cl.bg + ';border-color:' + cl.color + ';">' +
-        '<div style="font-size:18px;font-weight:700;color:' + cl.color + ';">' + cl.text + '</div>' +
-        '<div style="font-size:13px;color:var(--g600);margin-top:4px;">' + label + ': ' + value + ' ' + unit + '</div>' +
-      '</div>' +
-      '<div class="calc-result-grid">' +
-        '<div class="calc-result-item"><div class="calc-result-label">Percentile</div><div class="calc-result-value">' + pctl + '<span style="font-size:12px;">th</span></div></div>' +
-        '<div class="calc-result-item"><div class="calc-result-label">Z-Score</div><div class="calc-result-value" style="font-size:16px;">' + z.toFixed(2) + '</div></div>' +
-      '</div>';
-    }
-
     document.getElementById('btn-calc-growth').addEventListener('click', function() {
       var sex = document.getElementById('growth-sex').value;
       if (!sex) { showToast('Select sex', 'error'); return; }
diff --git a/public/js/calculators/growth.js b/public/js/calculators/growth.js
index 5f28133..9a8d9f4 100644
--- a/public/js/calculators/growth.js
+++ b/public/js/calculators/growth.js
@@ -36,6 +36,11 @@ export function normalCDF(z) {
   return 0.5 * (1 + sign * y);
 }
 
+export function valueFromLMS(L, M, S, z) {
+  if (Math.abs(L) < 0.001) return M * Math.exp(S * z);
+  return M * Math.pow(1 + L * S * z, 1 / L);
+}
+
 export function calcZFromLMS(value, L, M, S) {
   if (Math.abs(L) < 0.001) return Math.log(value / M) / S;
   return (Math.pow(value / M, L) - 1) / (L * S);
@@ -46,3 +51,26 @@ export function calculateLmsPercentile(lmsTable, x, value) {
   var z = calcZFromLMS(value, lms.L, lms.M, lms.S);
   return { lms: lms, z: z, percentile: normalCDF(z) * 100 };
 }
+
+export function calcMidParentalHeight(motherHt, fatherHt, sex) {
+  if (!motherHt || !fatherHt) return null;
+  var mph = sex === 'male' ? (motherHt + fatherHt + 13) / 2 : (motherHt + fatherHt - 13) / 2;
+  return { target: mph, low: mph - 8.5, high: mph + 8.5 };
+}
+
+export function renderGrowthResult(label, value, unit, z, percentile) {
+  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' };
+  else cl = { color: '#10b981', bg: '#d1fae5', text: pctl + 'th percentile' };
+
+  return '<div class="calc-result-header" style="background:' + cl.bg + ';border-color:' + cl.color + ';">' +
+    '<div style="font-size:18px;font-weight:700;color:' + cl.color + ';">' + cl.text + '</div>' +
+    '<div style="font-size:13px;color:var(--g600);margin-top:4px;">' + label + ': ' + value + ' ' + unit + '</div>' +
+  '</div>' +
+  '<div class="calc-result-grid">' +
+    '<div class="calc-result-item"><div class="calc-result-label">Percentile</div><div class="calc-result-value">' + pctl + '<span style="font-size:12px;">th</span></div></div>' +
+    '<div class="calc-result-item"><div class="calc-result-label">Z-Score</div><div class="calc-result-value" style="font-size:16px;">' + z.toFixed(2) + '</div></div>' +
+  '</div>';
+}
diff --git a/test/calculators-data.test.js b/test/calculators-data.test.js
index 6182f15..9a2601c 100644
--- a/test/calculators-data.test.js
+++ b/test/calculators-data.test.js
@@ -350,6 +350,16 @@ test('growth calculator preserves legacy outputs across chart combinations', asy
   });
 });
 
+test('growth helper exports preserve mid-parental height and result rendering', async () => {
+  const growth = await import('../public/js/calculators/growth.js');
+  assert.deepEqual(growth.calcMidParentalHeight(160, 180, 'male'), { target: 176.5, low: 168, high: 185 });
+  assert.deepEqual(growth.calcMidParentalHeight(160, 180, 'female'), { target: 163.5, low: 155, high: 172 });
+  assert.equal(Number(growth.valueFromLMS(1, 75, 0.03, 0).toFixed(2)), 75);
+  const html = growth.renderGrowthResult('Weight-for-Age', 8, 'kg', 0.07, 52.79);
+  assert.match(html, /52\.79<span style="font-size:12px;">th/);
+  assert.match(html, /Weight-for-Age: 8 kg/);
+});
+
 test('bp-reference.json exposes complete height LMS and coefficient tables', () => {
   const raw = fs.readFileSync(path.join(__dirname, '..', 'public', 'data', 'calculators', 'bp-reference.json'), 'utf8');
   const data = JSON.parse(raw);