diff --git a/src/__tests__/main/parsers/usage-aggregator.test.ts b/src/__tests__/main/parsers/usage-aggregator.test.ts
index 7e0e0c6e..2ba0d20e 100644
--- a/src/__tests__/main/parsers/usage-aggregator.test.ts
+++ b/src/__tests__/main/parsers/usage-aggregator.test.ts
@@ -99,7 +99,8 @@ describe('estimateContextUsage', () => {
         contextWindow: 200000,
       });
       const result = estimateContextUsage(stats, 'claude-code');
-      expect(result).toBe(100);
+      // Output tokens excluded; 150k / 200k = 75%
+      expect(result).toBe(75);
     });
   });
 
@@ -113,7 +114,7 @@ describe('estimateContextUsage', () => {
     it('should use codex default context window (200k)', () => {
       const stats = createStats({ contextWindow: 0 });
       const result = estimateContextUsage(stats, 'codex');
-      expect(result).toBe(8);
+      expect(result).toBe(5);
     });
 
     it('should use opencode default context window (128k)', () => {
diff --git a/src/__tests__/renderer/components/HistoryDetailModal.test.tsx b/src/__tests__/renderer/components/HistoryDetailModal.test.tsx
index f12cfd85..eee8f8a2 100644
--- a/src/__tests__/renderer/components/HistoryDetailModal.test.tsx
+++ b/src/__tests__/renderer/components/HistoryDetailModal.test.tsx
@@ -642,7 +642,7 @@ describe('HistoryDetailModal', () => {
             usageStats: {
               inputTokens: 74000,
               outputTokens: 1000,
-              cacheReadInputTokens: 0,
+              cacheReadInputTokens: 1000,
               cacheCreationInputTokens: 0,
               contextWindow: 100000,
               totalCostUsd: 0,
@@ -652,7 +652,7 @@ describe('HistoryDetailModal', () => {
         />
       );
 
-      // (74000 + 1000) / 100000 = 75%
+      // (74000 + 1000 cache read) / 100000 = 75%
       expect(screen.getByText('75%')).toBeInTheDocument();
     });
 
diff --git a/src/__tests__/renderer/components/MainPanel.test.tsx b/src/__tests__/renderer/components/MainPanel.test.tsx
index afeb7dcd..891b01dd 100644
--- a/src/__tests__/renderer/components/MainPanel.test.tsx
+++ b/src/__tests__/renderer/components/MainPanel.test.tsx
@@ -1794,8 +1794,8 @@ describe('MainPanel', () => {
           createdAt: Date.now(),
           usageStats: {
             inputTokens: 50000,
-            outputTokens: 25000,
-            cacheReadInputTokens: 0,
+            outputTokens: 0,
+            cacheReadInputTokens: 25000,
             cacheCreationInputTokens: 0,
             totalCostUsd: 0.05,
             contextWindow: 200000,
@@ -1806,7 +1806,7 @@ describe('MainPanel', () => {
 
       render(<MainPanel {...defaultProps} activeSession={session} getContextColor={getContextColor} />);
 
-      // Context usage should be (50000 + 25000) / 200000 * 100 = 37.5%
+      // Context usage should be (50000 + 25000 cache read) / 200000 * 100 = 37.5%
       expect(getContextColor).toHaveBeenCalledWith(38, theme); // Rounded to 38
     });
   });
diff --git a/src/__tests__/renderer/components/TabSwitcherModal.test.tsx b/src/__tests__/renderer/components/TabSwitcherModal.test.tsx
index 2644c8e7..daeea226 100644
--- a/src/__tests__/renderer/components/TabSwitcherModal.test.tsx
+++ b/src/__tests__/renderer/components/TabSwitcherModal.test.tsx
@@ -61,8 +61,8 @@ const createTestTab = (overrides: Partial<AITab> = {}): AITab => ({
   usageStats: {
     inputTokens: 1000,
     outputTokens: 500,
-    cacheReadTokens: 0,
-    cacheWriteTokens: 0,
+    cacheReadInputTokens: 0,
+    cacheCreationInputTokens: 0,
     totalCostUsd: 0.05,
     contextWindow: 200000,
   },
@@ -104,8 +104,8 @@ describe('TabSwitcherModal', () => {
           usageStats: {
             inputTokens: 500,
             outputTokens: 200,
-            cacheReadTokens: 0,
-            cacheWriteTokens: 0,
+            cacheReadInputTokens: 0,
+            cacheCreationInputTokens: 0,
             totalCostUsd: 0.01,
             contextWindow: 200000,
           },
@@ -132,8 +132,8 @@ describe('TabSwitcherModal', () => {
           usageStats: {
             inputTokens: 5000,
             outputTokens: 3500,
-            cacheReadTokens: 0,
-            cacheWriteTokens: 0,
+            cacheReadInputTokens: 0,
+            cacheCreationInputTokens: 0,
             totalCostUsd: 0.10,
             contextWindow: 200000,
           },
@@ -160,8 +160,8 @@ describe('TabSwitcherModal', () => {
           usageStats: {
             inputTokens: 700,
             outputTokens: 300,
-            cacheReadTokens: 0,
-            cacheWriteTokens: 0,
+            cacheReadInputTokens: 0,
+            cacheCreationInputTokens: 0,
             totalCostUsd: 0.02,
             contextWindow: 200000,
           },
@@ -189,8 +189,8 @@ describe('TabSwitcherModal', () => {
           usageStats: {
             inputTokens: 100,
             outputTokens: 50,
-            cacheReadTokens: 0,
-            cacheWriteTokens: 0,
+            cacheReadInputTokens: 0,
+            cacheCreationInputTokens: 0,
             totalCostUsd: 0,
             contextWindow: 200000,
           },
@@ -216,8 +216,8 @@ describe('TabSwitcherModal', () => {
           usageStats: {
             inputTokens: 100,
             outputTokens: 50,
-            cacheReadTokens: 0,
-            cacheWriteTokens: 0,
+            cacheReadInputTokens: 0,
+            cacheCreationInputTokens: 0,
             totalCostUsd: 0.005,
             contextWindow: 200000,
           },
@@ -243,8 +243,8 @@ describe('TabSwitcherModal', () => {
           usageStats: {
             inputTokens: 1000,
             outputTokens: 500,
-            cacheReadTokens: 0,
-            cacheWriteTokens: 0,
+            cacheReadInputTokens: 0,
+            cacheCreationInputTokens: 0,
             totalCostUsd: 1.23,
             contextWindow: 200000,
           },
@@ -501,8 +501,8 @@ describe('TabSwitcherModal', () => {
           usageStats: {
             inputTokens: 1000,
             outputTokens: 500,
-            cacheReadTokens: 0,
-            cacheWriteTokens: 0,
+            cacheReadInputTokens: 0,
+            cacheCreationInputTokens: 0,
             totalCostUsd: 0.05,
             contextWindow: 0,
           },
@@ -527,10 +527,10 @@ describe('TabSwitcherModal', () => {
       it('calculates correct percentage', () => {
         const tab = createTestTab({
           usageStats: {
-            inputTokens: 10000,
+            inputTokens: 20000,
             outputTokens: 10000,
-            cacheReadTokens: 0,
-            cacheWriteTokens: 0,
+            cacheReadInputTokens: 0,
+            cacheCreationInputTokens: 0,
             totalCostUsd: 0.50,
             contextWindow: 100000,
           },
@@ -556,9 +556,9 @@ describe('TabSwitcherModal', () => {
         const tab = createTestTab({
           usageStats: {
             inputTokens: 150000,
-            outputTokens: 100000,
-            cacheReadTokens: 0,
-            cacheWriteTokens: 0,
+            outputTokens: 0,
+            cacheReadInputTokens: 100000,
+            cacheCreationInputTokens: 0,
             totalCostUsd: 5.00,
             contextWindow: 200000,
           },
@@ -810,8 +810,8 @@ describe('TabSwitcherModal', () => {
         usageStats: {
           inputTokens: 10000,
           outputTokens: 10000,
-          cacheReadTokens: 0,
-          cacheWriteTokens: 0,
+          cacheReadInputTokens: 0,
+          cacheCreationInputTokens: 0,
           totalCostUsd: 0.50,
           contextWindow: 100000,
         },
@@ -842,10 +842,10 @@ describe('TabSwitcherModal', () => {
     it('applies color based on percentage (success for low)', () => {
       const tab = createTestTab({
         usageStats: {
-          inputTokens: 5000,
+          inputTokens: 10000,
           outputTokens: 5000,
-          cacheReadTokens: 0,
-          cacheWriteTokens: 0,
+          cacheReadInputTokens: 0,
+          cacheCreationInputTokens: 0,
           totalCostUsd: 0.25,
           contextWindow: 200000,
         },
diff --git a/src/__tests__/renderer/utils/contextExtractor.test.ts b/src/__tests__/renderer/utils/contextExtractor.test.ts
index 57535841..6d46e355 100644
--- a/src/__tests__/renderer/utils/contextExtractor.test.ts
+++ b/src/__tests__/renderer/utils/contextExtractor.test.ts
@@ -94,8 +94,8 @@ describe('extractTabContext', () => {
       usageStats: {
         inputTokens: 100,
         outputTokens: 200,
-        cacheReadTokens: 50,
-        cacheCreationTokens: 0,
+        cacheReadInputTokens: 50,
+        cacheCreationInputTokens: 0,
         costUsd: 0.01,
       },
     });
@@ -424,15 +424,15 @@ describe('estimateTokenCount', () => {
       usageStats: {
         inputTokens: 500,
         outputTokens: 1000,
-        cacheReadTokens: 0,
-        cacheCreationTokens: 0,
+        cacheReadInputTokens: 0,
+        cacheCreationInputTokens: 200,
         costUsd: 0.05,
       },
     };
 
     const tokens = estimateTokenCount(context);
 
-    expect(tokens).toBe(1500);
+    expect(tokens).toBe(700); // input + cacheCreation + cacheRead
   });
 
   it('should estimate from log content when no usage stats', () => {
@@ -614,7 +614,13 @@ describe('calculateTotalTokens', () => {
         name: 'Context 1',
         logs: [],
         agentType: 'claude-code',
-        usageStats: { inputTokens: 100, outputTokens: 200, cacheReadTokens: 0, cacheCreationTokens: 0, costUsd: 0 },
+        usageStats: {
+          inputTokens: 100,
+          outputTokens: 200,
+          cacheReadInputTokens: 50,
+          cacheCreationInputTokens: 25,
+          costUsd: 0,
+        },
       },
       {
         type: 'tab',
@@ -623,13 +629,20 @@ describe('calculateTotalTokens', () => {
         name: 'Context 2',
         logs: [],
         agentType: 'claude-code',
-        usageStats: { inputTokens: 300, outputTokens: 400, cacheReadTokens: 0, cacheCreationTokens: 0, costUsd: 0 },
+        usageStats: {
+          inputTokens: 300,
+          outputTokens: 400,
+          cacheReadInputTokens: 75,
+          cacheCreationInputTokens: 25,
+          costUsd: 0,
+        },
       },
     ];
 
     const total = calculateTotalTokens(contexts);
 
-    expect(total).toBe(1000); // (100+200) + (300+400)
+    // input + cacheCreation + cacheRead for each context
+    expect(total).toBe(575); // (100+25+50) + (300+25+75)
   });
 });
 
@@ -643,7 +656,13 @@ describe('getContextSummary', () => {
         name: 'Context 1',
         logs: [createMockLog(), createMockLog()],
         agentType: 'claude-code',
-        usageStats: { inputTokens: 100, outputTokens: 100, cacheReadTokens: 0, cacheCreationTokens: 0, costUsd: 0 },
+        usageStats: {
+          inputTokens: 100,
+          outputTokens: 100,
+          cacheReadInputTokens: 50,
+          cacheCreationInputTokens: 25,
+          costUsd: 0,
+        },
       },
       {
         type: 'session',
@@ -652,7 +671,13 @@ describe('getContextSummary', () => {
         name: 'Context 2',
         logs: [createMockLog(), createMockLog(), createMockLog()],
         agentType: 'opencode',
-        usageStats: { inputTokens: 200, outputTokens: 200, cacheReadTokens: 0, cacheCreationTokens: 0, costUsd: 0 },
+        usageStats: {
+          inputTokens: 200,
+          outputTokens: 200,
+          cacheReadInputTokens: 75,
+          cacheCreationInputTokens: 25,
+          costUsd: 0,
+        },
       },
     ];
 
@@ -660,7 +685,7 @@ describe('getContextSummary', () => {
 
     expect(summary.totalSources).toBe(2);
     expect(summary.totalLogs).toBe(5);
-    expect(summary.estimatedTokens).toBe(600);
+    expect(summary.estimatedTokens).toBe(475);
     expect(summary.byAgent['claude-code']).toBe(1);
     expect(summary.byAgent['opencode']).toBe(1);
   });
diff --git a/src/__tests__/renderer/utils/contextUsage.test.ts b/src/__tests__/renderer/utils/contextUsage.test.ts
index bd78013f..f1893c4a 100644
--- a/src/__tests__/renderer/utils/contextUsage.test.ts
+++ b/src/__tests__/renderer/utils/contextUsage.test.ts
@@ -72,13 +72,13 @@ describe('estimateContextUsage', () => {
     it('should use claude default context window (200k)', () => {
       const stats = createStats({ contextWindow: 0 });
       const result = estimateContextUsage(stats, 'claude');
-      expect(result).toBe(8);
+      expect(result).toBe(5);
     });
 
     it('should use codex default context window (200k)', () => {
       const stats = createStats({ contextWindow: 0 });
       const result = estimateContextUsage(stats, 'codex');
-      expect(result).toBe(8);
+      expect(result).toBe(5);
     });
 
     it('should use opencode default context window (128k)', () => {
@@ -91,7 +91,7 @@ describe('estimateContextUsage', () => {
     it('should use aider default context window (128k)', () => {
       const stats = createStats({ contextWindow: 0 });
       const result = estimateContextUsage(stats, 'aider');
-      expect(result).toBe(12);
+      expect(result).toBe(8);
     });
 
     it('should return null for terminal agent', () => {
@@ -151,7 +151,7 @@ describe('estimateContextUsage', () => {
       const stats = createStats({ contextWindow: -100 });
       const result = estimateContextUsage(stats, 'claude-code');
       // Should use fallback since contextWindow is invalid
-      expect(result).toBe(8);
+      expect(result).toBe(5);
     });
 
     it('should handle undefined context window', () => {
@@ -160,7 +160,7 @@ describe('estimateContextUsage', () => {
       stats.contextWindow = undefined;
       const result = estimateContextUsage(stats, 'claude-code');
       // Should use fallback
-      expect(result).toBe(8);
+      expect(result).toBe(5);
     });
 
     it('should handle very large token counts', () => {
diff --git a/src/__tests__/web/mobile/SessionStatusBanner.test.tsx b/src/__tests__/web/mobile/SessionStatusBanner.test.tsx
index 96f79e10..24a6cc1b 100644
--- a/src/__tests__/web/mobile/SessionStatusBanner.test.tsx
+++ b/src/__tests__/web/mobile/SessionStatusBanner.test.tsx
@@ -417,7 +417,7 @@ describe('SessionStatusBanner', () => {
 
     it('shows warning color (yellow) for usage 70-89%', () => {
       const usageStats = createUsageStats({
-        inputTokens: 100000,
+        inputTokens: 160000,
         outputTokens: 60000,
         contextWindow: 200000,
       });
@@ -464,7 +464,7 @@ describe('SessionStatusBanner', () => {
 
     it('shows warning color at exactly 70%', () => {
       const usageStats = createUsageStats({
-        inputTokens: 70000,
+        inputTokens: 140000,
         outputTokens: 70000,
         contextWindow: 200000,
       });
@@ -770,7 +770,7 @@ describe('SessionStatusBanner', () => {
   describe('ContextUsageBar component', () => {
     it('renders progressbar with correct ARIA attributes', () => {
       const usageStats = createUsageStats({
-        inputTokens: 50000,
+        inputTokens: 100000,
         outputTokens: 50000,
         contextWindow: 200000,
       });
@@ -786,7 +786,7 @@ describe('SessionStatusBanner', () => {
 
     it('has accessible aria-label', () => {
       const usageStats = createUsageStats({
-        inputTokens: 50000,
+        inputTokens: 100000,
         outputTokens: 50000,
         contextWindow: 200000,
       });
@@ -799,7 +799,7 @@ describe('SessionStatusBanner', () => {
 
     it('has descriptive title', () => {
       const usageStats = createUsageStats({
-        inputTokens: 50000,
+        inputTokens: 100000,
         outputTokens: 50000,
         contextWindow: 200000,
       });
@@ -1285,7 +1285,7 @@ describe('SessionStatusBanner', () => {
         // Tokens
         expect(screen.getByText('7.0K')).toBeInTheDocument();
         // Context usage
-        expect(screen.getByText('4%')).toBeInTheDocument();
+        expect(screen.getByText('3%')).toBeInTheDocument();
         // Last response section
         expect(screen.getByText(/5m ago/)).toBeInTheDocument();
       });
@@ -1443,7 +1443,7 @@ describe('SessionStatusBanner', () => {
       expect(screen.getByText('AI')).toBeInTheDocument();
       expect(screen.getByText('$2.50')).toBeInTheDocument();
       expect(screen.getByText('180.0K')).toBeInTheDocument();
-      expect(screen.getByText('90%')).toBeInTheDocument();
+      expect(screen.getByText('75%')).toBeInTheDocument();
       expect(screen.getByText('1:05')).toBeInTheDocument();
       expect(screen.getByLabelText('AI is thinking')).toBeInTheDocument();
     });
diff --git a/src/renderer/components/HistoryDetailModal.tsx b/src/renderer/components/HistoryDetailModal.tsx
index 8d578ffe..9fed6607 100644
--- a/src/renderer/components/HistoryDetailModal.tsx
+++ b/src/renderer/components/HistoryDetailModal.tsx
@@ -343,9 +343,11 @@ export function HistoryDetailModal({
                     </span>
                   </div>
                   {(() => {
-                    // Context usage = (input + output + cache read) / context window
-                    // Cache read tokens represent the conversation history sent with each request
-                    const contextTokens = entry.usageStats!.inputTokens + entry.usageStats!.outputTokens + (entry.usageStats!.cacheReadInputTokens || 0);
+                    // Context usage = (input + cache creation + cache read) / context window
+                    const contextTokens =
+                      entry.usageStats!.inputTokens +
+                      (entry.usageStats!.cacheCreationInputTokens || 0) +
+                      (entry.usageStats!.cacheReadInputTokens || 0);
                     const contextUsage = Math.min(100, Math.round((contextTokens / entry.usageStats!.contextWindow) * 100));
                     return (
                       <div className="flex flex-col gap-1">