diff --git a/index.html b/index.html
index 58ad16f..9d53f2a 100644
--- a/index.html
+++ b/index.html
@@ -445,7 +445,8 @@ function save() {
 // COMPUTED HELPERS
 // ══════════════════════════════════════════════════════
 function blockMean(blockId) {
-  const graded = S.courses.filter(c => c.blockId === blockId && c.grade != null && c.grade !== '');
+  // passFail courses are excluded from the mean
+  const graded = S.courses.filter(c => c.blockId === blockId && !c.passFail && c.grade != null && c.grade !== '');
   if (!graded.length) return null;
   const sumWeighted = graded.reduce((s, c) => s + +c.grade * (+c.credits || 0), 0);
   const sumCoef     = graded.reduce((s, c) => s + (+c.credits || 0), 0);
@@ -455,6 +456,7 @@ function blockMean(blockId) {
 
 // status: 'pass' | 'fail' | 'prog'
 function status(course) {
+  if (course.passFail) return 'pass'; // pass/fail courses always count as passed
   if (course.grade == null || course.grade === '') return 'prog';
   if (+course.grade >= 4) return 'pass';
   if (course.blockId) {
@@ -475,7 +477,8 @@ function gradeClass(g) {
   return +g >= 5 ? 'g-high' : +g >= 4 ? 'g-mid' : 'g-low';
 }
 
-function fmtGrade(g) {
+function fmtGrade(g, passFail) {
+  if (passFail) return '<span style="font-size:11px;font-weight:600;color:var(--success)">P/F</span>';
   if (g == null || g === '') return '—';
   const n = +g;
   return Number.isInteger(n) ? String(n) : n.toFixed(2).replace(/0+$/, '').replace(/\.$/, '');
@@ -543,11 +546,14 @@ function renderDash() {
 
 function dashGlobal() {
   const all    = S.courses;
-  const graded = all.filter(c => c.grade != null && c.grade !== '');
+  // passFail courses excluded from mean, but count for credits/pass rate denominator
+  const graded = all.filter(c => !c.passFail && c.grade != null && c.grade !== '');
   const passed = all.filter(c => status(c) === 'pass');
   const totCr  = all.reduce((s, c) => s + (+c.credits || 0), 0);
   const passCr = passed.reduce((s, c) => s + (+c.credits || 0), 0);
-  const mean   = graded.length ? graded.reduce((s, c) => s + +c.grade, 0) / graded.length : null;
+  const sumW   = graded.reduce((s, c) => s + +c.grade * (+c.credits || 0), 0);
+  const sumC   = graded.reduce((s, c) => s + (+c.credits || 0), 0);
+  const mean   = sumC > 0 ? sumW / sumC : null;
   const passedGraded = graded.filter(c => status(c) === 'pass').length;
   const rate   = graded.length ? Math.round(passedGraded / graded.length * 100) : null;
 
@@ -568,7 +574,7 @@ function dashGlobal() {
     html += `<tr class="clickable" onclick="showCourseModal('${c.id}')">
       <td><div style="font-weight:500">${esc(c.name)}</div><div style="font-size:10px;color:var(--gray-400)">${semName(c.semesterId)}</div></td>
       <td>${c.credits || '—'}</td>
-      <td class="${gradeClass(c.grade)}">${fmtGrade(c.grade)}</td>
+      <td class="${c.passFail ? '' : gradeClass(c.grade)}">${fmtGrade(c.grade, c.passFail)}</td>
       <td>${badge(st)}</td>
     </tr>`;
   });
@@ -636,8 +642,10 @@ function dashSemesters() {
     const sc = S.courses.filter(c => c.semesterId === sem.id);
     const totCr  = sc.reduce((s, c) => s + (+c.credits || 0), 0);
     const passCr = sc.filter(c => status(c) === 'pass').reduce((s, c) => s + (+c.credits || 0), 0);
-    const graded = sc.filter(c => c.grade != null && c.grade !== '');
-    const mean   = graded.length ? graded.reduce((s, c) => s + +c.grade, 0) / graded.length : null;
+    const graded = sc.filter(c => !c.passFail && c.grade != null && c.grade !== '');
+    const sumW   = graded.reduce((s, c) => s + +c.grade * (+c.credits || 0), 0);
+    const sumC   = graded.reduce((s, c) => s + (+c.credits || 0), 0);
+    const mean   = sumC > 0 ? sumW / sumC : null;
 
     html += `<div class="card"><div class="card-header">
       <span class="card-title">${esc(sem.name)}</span>
@@ -669,7 +677,7 @@ function coursesMiniTable(courses, showMeta) {
     rows += `<tr class="clickable" onclick="showCourseModal('${c.id}')">
       <td><div style="font-weight:500">${esc(c.name)}</div>${meta ? `<div style="font-size:10px;color:var(--gray-400)">${meta}</div>` : ''}</td>
       <td>${c.credits || '—'}</td>
-      <td class="${gradeClass(c.grade)}">${fmtGrade(c.grade)}</td>
+      <td class="${c.passFail ? '' : gradeClass(c.grade)}">${fmtGrade(c.grade, c.passFail)}</td>
       <td>${badge(st)}</td>
     </tr>`;
   });
@@ -835,6 +843,7 @@ function showCourseModal(id) {
   const curPlan  = c ? (c.planId || '') : '';
   const curBlock = c ? (c.blockId || '') : '';
   const blockOpts = buildBlockOpts(curPlan, curBlock);
+  const isPF = c ? !!c.passFail : false;
 
   openModal(`<div class="modal">
     <div class="modal-header">
@@ -850,11 +859,15 @@ function showCourseModal(id) {
         <label>Credits *</label>
         <input id="f-credits" type="number" value="${c ? c.credits : ''}" placeholder="e.g. 3" min="0" step="0.5">
       </div>
-      <div class="form-group">
+      <div class="form-group" id="fg-grade" style="display:${isPF ? 'none' : 'block'}">
         <label>Grade (1 – 6)</label>
-        <input id="f-grade" type="number" value="${c && c.grade != null && c.grade !== '' ? c.grade : ''}" placeholder="e.g. 5.5" min="1" max="6" step="0.25">
+        <input id="f-grade" type="number" value="${c && !isPF && c.grade != null && c.grade !== '' ? c.grade : ''}" placeholder="e.g. 5.5" min="1" max="6" step="0.25">
       </div>
     </div>
+    <div class="form-group" style="display:flex;align-items:center;gap:10px;padding:4px 0">
+      <input type="checkbox" id="f-passfail" style="width:18px;height:18px;cursor:pointer;flex-shrink:0" ${isPF ? 'checked' : ''} onchange="onPassFailChange(this.checked)">
+      <label for="f-passfail" style="text-transform:none;font-size:14px;font-weight:500;color:var(--gray-700);cursor:pointer;letter-spacing:0">Passed (no grade — excluded from means)</label>
+    </div>
     <div class="form-group">
       <label>Semester</label>
       <select id="f-semester">
@@ -895,25 +908,32 @@ function onPlanChange(pid) {
   else     { fg.style.display = 'none'; }
 }
 
+function onPassFailChange(checked) {
+  const fgGrade = document.getElementById('fg-grade');
+  if (fgGrade) fgGrade.style.display = checked ? 'none' : 'block';
+}
+
 function saveCourse(id) {
-  const name    = document.getElementById('f-name').value.trim();
-  const credits = document.getElementById('f-credits').value;
-  const gradeV  = document.getElementById('f-grade').value;
-  const semId   = document.getElementById('f-semester').value;
-  const planId  = document.getElementById('f-plan').value;
-  const fg      = document.getElementById('fg-block');
-  const blockId = (fg && fg.style.display !== 'none') ? document.getElementById('f-block').value : '';
+  const name     = document.getElementById('f-name').value.trim();
+  const credits  = document.getElementById('f-credits').value;
+  const passFail = document.getElementById('f-passfail').checked;
+  const gradeEl  = document.getElementById('f-grade');
+  const gradeV   = (!passFail && gradeEl) ? gradeEl.value : '';
+  const semId    = document.getElementById('f-semester').value;
+  const planId   = document.getElementById('f-plan').value;
+  const fg       = document.getElementById('fg-block');
+  const blockId  = (fg && fg.style.display !== 'none') ? document.getElementById('f-block').value : '';
 
   if (!name)    { alert('Please enter a course name.'); return; }
   if (!credits || +credits < 0) { alert('Please enter valid credits.'); return; }
 
-  const grade = gradeV !== '' ? parseFloat(gradeV) : null;
+  const grade = (!passFail && gradeV !== '') ? parseFloat(gradeV) : null;
 
   if (id) {
     const i = S.courses.findIndex(c => c.id === id);
-    if (i >= 0) S.courses[i] = { id, name, credits: +credits, semesterId: semId, grade, planId, blockId };
+    if (i >= 0) S.courses[i] = { id, name, credits: +credits, semesterId: semId, grade, planId, blockId, passFail };
   } else {
-    S.courses.push({ id: uid(), name, credits: +credits, semesterId: semId, grade, planId, blockId });
+    S.courses.push({ id: uid(), name, credits: +credits, semesterId: semId, grade, planId, blockId, passFail });
   }
 
   save(); closeModal(); render(page);