diff --git a/src/app/[exam]/assess/[domain]/AssessmentClient.tsx b/src/app/[exam]/assess/[domain]/AssessmentClient.tsx
index ce669c8..e4e6f8e 100644
--- a/src/app/[exam]/assess/[domain]/AssessmentClient.tsx
+++ b/src/app/[exam]/assess/[domain]/AssessmentClient.tsx
@@ -10,6 +10,7 @@ import { Badge } from '@/components/ui/badge';
 import { QuestionCard } from '@/components/assess/QuestionCard';
 import { Clock, CheckCircle, XCircle, Target } from 'lucide-react';
 import type { Question } from '@/types/domain';
+import { MASTERY_THRESHOLD, APPROACHING_THRESHOLD } from '@/lib/constants';
 import type { QuestionAnswer, AssessmentResult } from '@/types/assessment';
 
 interface AssessmentClientProps {
@@ -153,8 +154,8 @@ export function AssessmentClient({ examId, domainId, topicId, questions }: Asses
 
               <ProgressIndicator value={result.score} className="h-3 w-full max-w-md" />
 
-              <Badge variant={result.score >= 85 ? 'default' : result.score >= 60 ? 'secondary' : 'destructive'} className="text-base px-4 py-2">
-                {result.score >= 85 ? 'Excellent!' : result.score >= 60 ? 'Good Progress' : 'Needs Review'}
+              <Badge variant={result.score >= MASTERY_THRESHOLD ? 'default' : result.score >= APPROACHING_THRESHOLD ? 'secondary' : 'destructive'} className="text-base px-4 py-2">
+                {result.score >= MASTERY_THRESHOLD ? 'Excellent!' : result.score >= APPROACHING_THRESHOLD ? 'Good Progress' : 'Needs Review'}
               </Badge>
             </div>
           </CardContent>
diff --git a/src/components/dashboard/DashboardHero.tsx b/src/components/dashboard/DashboardHero.tsx
index 25aa234..8d94ea1 100644
--- a/src/components/dashboard/DashboardHero.tsx
+++ b/src/components/dashboard/DashboardHero.tsx
@@ -1,3 +1,4 @@
+import { MASTERY_THRESHOLD } from "@/lib/constants";
 import Link from "next/link";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -30,7 +31,7 @@ function getCTA(examId: string, overall: OverallProgress, domains: DomainProgres
   }
 
   // Exam ready - 85%+ mastery
-  if (overall.masteryScore >= 85) {
+  if (overall.masteryScore >= MASTERY_THRESHOLD) {
     return {
       text: "Review Your Progress",
       href: `/${examId}/progress`,
diff --git a/src/components/progress/ReadinessCard.tsx b/src/components/progress/ReadinessCard.tsx
index de85f61..951d8f9 100644
--- a/src/components/progress/ReadinessCard.tsx
+++ b/src/components/progress/ReadinessCard.tsx
@@ -5,6 +5,7 @@ import { ChevronDown, ChevronRight, Info } from 'lucide-react';
 import { Collapsible, CollapsibleContent, CollapsibleTrigger } from '@/components/ui/collapsible';
 import { ProgressIndicator } from '@/components/ui/progress-indicator';
 import type { ReadinessEstimate, DomainReadiness } from '@/lib/progress/calculator';
+import { MASTERY_THRESHOLD, APPROACHING_THRESHOLD } from '@/lib/constants';
 import { clsx } from 'clsx';
 
 interface ReadinessCardProps {
@@ -116,7 +117,7 @@ export function ReadinessCard({ estimate, examId }: ReadinessCardProps) {
 function DomainBar({ domain }: { domain: DomainReadiness }) {
   const [expanded, setExpanded] = useState(false);
   const masteryRounded = Math.round(domain.mastery);
-  const colorClass = masteryRounded >= 85 ? 'text-green-600' : masteryRounded >= 60 ? 'text-amber-600' : 'text-red-600';
+  const colorClass = masteryRounded >= MASTERY_THRESHOLD ? 'text-green-600' : masteryRounded >= APPROACHING_THRESHOLD ? 'text-amber-600' : 'text-red-600';
   const hasWeakTopics = domain.weakTopics.length > 0;
 
   return (
diff --git a/src/components/ui/progress-indicator.tsx b/src/components/ui/progress-indicator.tsx
index 857104a..4885928 100644
--- a/src/components/ui/progress-indicator.tsx
+++ b/src/components/ui/progress-indicator.tsx
@@ -1,5 +1,6 @@
 "use client"
 
+import { MASTERY_THRESHOLD, APPROACHING_THRESHOLD } from '@/lib/constants';
 import { cn } from '@/lib/utils';
 import * as ProgressPrimitive from "@radix-ui/react-progress";
 
@@ -16,8 +17,8 @@ interface ProgressIndicatorProps {
  */
 export function ProgressIndicator({ value, className }: ProgressIndicatorProps) {
   const indicatorColorClass =
-    value >= 85 ? 'bg-green-600' :
-    value >= 60 ? 'bg-amber-500' :
+    value >= MASTERY_THRESHOLD ? 'bg-green-600' :
+    value >= APPROACHING_THRESHOLD ? 'bg-amber-500' :
     'bg-red-600';
 
   return (
diff --git a/src/lib/constants.ts b/src/lib/constants.ts
new file mode 100644
index 0000000..f951be1
--- /dev/null
+++ b/src/lib/constants.ts
@@ -0,0 +1,14 @@
+/** Score at or above which a topic is considered "mastered" / "exam ready" */
+export const MASTERY_THRESHOLD = 85;
+
+/** Score at or above which a topic is considered "developing" */
+export const APPROACHING_THRESHOLD = 60;
+
+/** Score at or above which readiness level is "approaching" (vs "building") */
+export const READINESS_APPROACHING_THRESHOLD = 65;
+
+/** Score at or above which dashboard tips switch to exam-prep category */
+export const EXAM_PREP_THRESHOLD = 75;
+
+/** Decimal equivalent for SQL queries (mastery_level is 0-1 scale) */
+export const MASTERY_THRESHOLD_DECIMAL = MASTERY_THRESHOLD / 100;
diff --git a/src/lib/content/sidebar.ts b/src/lib/content/sidebar.ts
index 0d5b230..6c7d600 100644
--- a/src/lib/content/sidebar.ts
+++ b/src/lib/content/sidebar.ts
@@ -1,3 +1,4 @@
+import { MASTERY_THRESHOLD } from '@/lib/constants';
 import { getAllDomains } from './loader';
 import { parseTopicSections } from './parser';
 import { getAllTopicWindowedMasteries } from '@/lib/progress/mastery';
@@ -111,7 +112,7 @@ export function getSidebarHierarchyWithProgress(examId: string): SidebarHierarch
         if (topicResult && topicResult.attempts > 0) {
           topicMasterySum += masteryScore;
           topicsWithProgress++;
-          if (masteryScore >= 85) topicsCompleted++;
+          if (masteryScore >= MASTERY_THRESHOLD) topicsCompleted++;
         }
 
         return {
diff --git a/src/lib/dashboard/tips.ts b/src/lib/dashboard/tips.ts
index 10a31ab..43dafc0 100644
--- a/src/lib/dashboard/tips.ts
+++ b/src/lib/dashboard/tips.ts
@@ -1,3 +1,5 @@
+import { EXAM_PREP_THRESHOLD } from '@/lib/constants';
+
 export interface Tip {
   id: string;
   category: "onboarding" | "assessment" | "study" | "feature" | "exam-prep";
@@ -136,7 +138,7 @@ function getTipCategory(state: UserState): Tip["category"] {
     return "onboarding";
   }
 
-  if (state.masteryScore >= 75) {
+  if (state.masteryScore >= EXAM_PREP_THRESHOLD) {
     return "exam-prep";
   }
 
diff --git a/src/lib/llm/tool-handlers.ts b/src/lib/llm/tool-handlers.ts
index 13d0fc5..29a8e96 100644
--- a/src/lib/llm/tool-handlers.ts
+++ b/src/lib/llm/tool-handlers.ts
@@ -1,3 +1,4 @@
+import { MASTERY_THRESHOLD } from '@/lib/constants';
 import { getTutorProgressContext } from '@/lib/progress/tutor-context';
 import { getAllDomains, getTopicById, getTopicQuestions } from '@/lib/content/loader';
 import { getLabMeta } from '@/lib/content/experiments';
@@ -466,7 +467,7 @@ export function handleSuggestNextStudyTopic(_params: Record<string, unknown>, ex
         }
 
         // Skip mastered topics
-        if (mastery >= 85) continue;
+        if (mastery >= MASTERY_THRESHOLD) continue;
 
         const finalScore = Math.round(baseScore * weightMultiplier);
 
diff --git a/src/lib/progress/calculator.ts b/src/lib/progress/calculator.ts
index 0962012..18f1799 100644
--- a/src/lib/progress/calculator.ts
+++ b/src/lib/progress/calculator.ts
@@ -1,6 +1,7 @@
 import { cache } from "react";
 import { db } from "@/lib/db/client";
 import { getAllDomains, getTopicById } from "@/lib/content/loader";
+import { MASTERY_THRESHOLD, MASTERY_THRESHOLD_DECIMAL, READINESS_APPROACHING_THRESHOLD } from "@/lib/constants";
 import { getAllTopicWindowedMasteries } from './mastery';
 import type { TopicMasteryResult } from './mastery';
 
@@ -132,7 +133,7 @@ export const getDomainProgress = cache((examId: string, domainId: string): Domai
   const topicStats = db.prepare(`
     SELECT
       COUNT(*) as topics_with_progress,
-      SUM(CASE WHEN mastery_level >= 0.85 THEN 1 ELSE 0 END) as completed_topics
+      SUM(CASE WHEN mastery_level >= ${MASTERY_THRESHOLD_DECIMAL} THEN 1 ELSE 0 END) as completed_topics
     FROM topic_progress
     WHERE exam_id = ? AND domain_id = ?
   `).get(examId, domainId) as { topics_with_progress: number; completed_topics: number };
@@ -336,7 +337,7 @@ export const getReadinessEstimate = cache((examId: string): ReadinessEstimate =>
       }
 
       // Topics below 85% are weak (including unstudied ones)
-      if (mastery < 85) {
+      if (mastery < MASTERY_THRESHOLD) {
         weakTopics.push({
           topicId: topic.meta.id,
           topicName: topic.meta.shortName,
@@ -378,9 +379,9 @@ export const getReadinessEstimate = cache((examId: string): ReadinessEstimate =>
 
   // Determine level
   let level: 'ready' | 'approaching' | 'building';
-  if (overallMastery >= 85) {
+  if (overallMastery >= MASTERY_THRESHOLD) {
     level = 'ready';
-  } else if (overallMastery >= 65) {
+  } else if (overallMastery >= READINESS_APPROACHING_THRESHOLD) {
     level = 'approaching';
   } else {
     level = 'building';
@@ -413,7 +414,7 @@ function getAllDomainProgressBatch(examId: string): DomainProgress[] {
     SELECT
       domain_id,
       COUNT(*) as topics_with_progress,
-      SUM(CASE WHEN mastery_level >= 0.85 THEN 1 ELSE 0 END) as completed_topics
+      SUM(CASE WHEN mastery_level >= ${MASTERY_THRESHOLD_DECIMAL} THEN 1 ELSE 0 END) as completed_topics
     FROM topic_progress
     WHERE exam_id = ?
     GROUP BY domain_id
diff --git a/src/lib/utils/colors.ts b/src/lib/utils/colors.ts
index 57569d2..80616dc 100644
--- a/src/lib/utils/colors.ts
+++ b/src/lib/utils/colors.ts
@@ -3,6 +3,7 @@
  * Tailwind cannot handle dynamic class names (e.g., `border-${color}-500`),
  * so we map domain color strings to hex values for use with style={{ }}.
  */
+import { MASTERY_THRESHOLD, APPROACHING_THRESHOLD } from '@/lib/constants';
 
 const DOMAIN_COLOR_HEX: Record<string, string> = {
   blue: '#3b82f6',
@@ -25,8 +26,8 @@ export function getDomainColorHex(color: string): string {
  * Uses Tailwind classes since these are static (known at build time).
  */
 export function getMasteryDotColorClass(score: number): string {
-  if (score >= 85) return 'bg-green-500';
-  if (score >= 60) return 'bg-amber-500';
+  if (score >= MASTERY_THRESHOLD) return 'bg-green-500';
+  if (score >= APPROACHING_THRESHOLD) return 'bg-amber-500';
   if (score > 0) return 'bg-red-500';
   return 'bg-muted-foreground/30';
 }
diff --git a/src/lib/utils/mastery.ts b/src/lib/utils/mastery.ts
index 98f2c23..682912c 100644
--- a/src/lib/utils/mastery.ts
+++ b/src/lib/utils/mastery.ts
@@ -2,13 +2,14 @@
  * Centralized mastery utilities for consistent display across the application.
  * Consolidates mastery scoring, labeling, and formatting functions.
  */
+import { MASTERY_THRESHOLD, APPROACHING_THRESHOLD } from '@/lib/constants';
 
 /**
  * Get mastery score color class based on threshold
  */
 export function getMasteryColorClass(score: number): string {
-  if (score >= 85) return "text-green-600";
-  if (score >= 60) return "text-amber-600";
+  if (score >= MASTERY_THRESHOLD) return "text-green-600";
+  if (score >= APPROACHING_THRESHOLD) return "text-amber-600";
   if (score > 0) return "text-red-600";
   return "text-muted-foreground";
 }
@@ -17,8 +18,8 @@ export function getMasteryColorClass(score: number): string {
  * Get mastery label based on score
  */
 export function getMasteryLabel(score: number): string {
-  if (score >= 85) return "Mastered";
-  if (score >= 60) return "Developing";
+  if (score >= MASTERY_THRESHOLD) return "Mastered";
+  if (score >= APPROACHING_THRESHOLD) return "Developing";
   if (score > 0) return "In Progress";
   return "Not Started";
 }
@@ -30,8 +31,8 @@ export function getMasteryStatus(score: number): {
   label: string;
   variant: "default" | "secondary" | "destructive" | "outline";
 } {
-  if (score >= 85) return { label: "Exam Ready", variant: "default" };
-  if (score >= 60) return { label: "Developing", variant: "secondary" };
+  if (score >= MASTERY_THRESHOLD) return { label: "Exam Ready", variant: "default" };
+  if (score >= APPROACHING_THRESHOLD) return { label: "Developing", variant: "secondary" };
   if (score > 0) return { label: "Building Foundation", variant: "outline" };
   return { label: "Not Started", variant: "outline" };
 }