diff --git a/src/App.tsx b/src/App.tsx
index e2ed838..5a29a59 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -112,8 +112,9 @@ function App() {
       // Use cached uploadedPesData if available, otherwise recalculate
       if (cachedUploadedPesData) {
         // Use the exact uploaded data from cache
-        // Calculate the adjusted offset (same logic as upload)
+        // Calculate the adjusted offset (same logic as upload hook)
         if (rotation !== 0) {
+          // Calculate center shift using the same helper as store selectors
           const originalCenter = calculatePatternCenter(originalPesData.bounds);
           const rotatedCenter = calculatePatternCenter(
             cachedUploadedPesData.bounds,
@@ -140,6 +141,7 @@ function App() {
         }
       } else if (rotation !== 0) {
         // Fallback: recalculate if no cached uploaded data (shouldn't happen for new uploads)
+        // This uses the same transformation logic as usePatternRotationUpload hook
         console.warn("[App] No cached uploaded data, recalculating rotation");
         const rotatedStitches = transformStitchesRotation(
           originalPesData.stitches,
@@ -152,6 +154,7 @@ function App() {
         const decoded = decodePenData(penData);
         const rotatedBounds = calculateBoundsFromDecodedStitches(decoded);
 
+        // Calculate center shift using the same helper as store selectors
         const originalCenter = calculatePatternCenter(originalPesData.bounds);
         const rotatedCenter = calculatePatternCenter(rotatedBounds);
         const centerShiftX = rotatedCenter.x - originalCenter.x;
diff --git a/src/components/PatternCanvas/PatternLayer.tsx b/src/components/PatternCanvas/PatternLayer.tsx
index c9d61f3..e6d1f1a 100644
--- a/src/components/PatternCanvas/PatternLayer.tsx
+++ b/src/components/PatternCanvas/PatternLayer.tsx
@@ -43,6 +43,9 @@ export const PatternLayer = memo(function PatternLayer({
   onTransformEnd,
   attachTransformer,
 }: PatternLayerProps) {
+  // Memoize center calculation - this is the pattern center calculation
+  // Note: We keep this local calculation here since the component receives
+  // pesData as a prop which could be either original or uploaded pattern
   const center = useMemo(
     () => calculatePatternCenter(pesData.bounds),
     [pesData.bounds],
diff --git a/src/hooks/domain/usePatternRotationUpload.ts b/src/hooks/domain/usePatternRotationUpload.ts
index 92d89d3..34b6260 100644
--- a/src/hooks/domain/usePatternRotationUpload.ts
+++ b/src/hooks/domain/usePatternRotationUpload.ts
@@ -42,6 +42,10 @@ export interface UsePatternRotationUploadReturn {
  * - Center shift calculation to maintain visual position
  * - Upload orchestration with proper caching
  *
+ * Note: This hook operates on passed parameters rather than store state,
+ * allowing it to be used as a callback handler. The center calculations
+ * use the same helpers as the store selectors for consistency.
+ *
  * @param params - Upload and store functions
  * @returns Upload handler function
  */
@@ -78,7 +82,8 @@ export function usePatternRotationUpload({
         // Calculate bounds from the DECODED stitches (the actual data that will be rendered)
         const rotatedBounds = calculateBoundsFromDecodedStitches(decoded);
 
-        // Calculate the center of the rotated pattern
+        // Calculate the center shift caused by rotation
+        // Uses the same calculatePatternCenter helper as store selectors
         const originalCenter = calculatePatternCenter(pesData.bounds);
         const rotatedCenter = calculatePatternCenter(rotatedBounds);
         const centerShiftX = rotatedCenter.x - originalCenter.x;
diff --git a/src/stores/usePatternStore.test.ts b/src/stores/usePatternStore.test.ts
new file mode 100644
index 0000000..04ebb26
--- /dev/null
+++ b/src/stores/usePatternStore.test.ts
@@ -0,0 +1,200 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import {
+  usePatternStore,
+  selectPatternCenter,
+  selectUploadedPatternCenter,
+  selectRotatedBounds,
+  selectRotationCenterShift,
+} from "./usePatternStore";
+import type { PesPatternData } from "../formats/import/pesImporter";
+
+// Mock pattern data for testing
+const createMockPesData = (
+  bounds = {
+    minX: -100,
+    maxX: 100,
+    minY: -50,
+    maxY: 50,
+  },
+): PesPatternData => ({
+  stitches: [[0, 0, 0, 0]],
+  threads: [],
+  uniqueColors: [],
+  penData: new Uint8Array(),
+  penStitches: {
+    stitches: [],
+    colorBlocks: [],
+    bounds: { minX: 0, maxX: 0, minY: 0, maxY: 0 },
+  },
+  colorCount: 1,
+  stitchCount: 1,
+  bounds,
+});
+
+describe("usePatternStore selectors", () => {
+  beforeEach(() => {
+    // Reset store state before each test
+    const state = usePatternStore.getState();
+    state.setPattern(createMockPesData(), "test.pes");
+    state.resetPatternOffset();
+    state.resetRotation();
+    state.clearUploadedPattern();
+  });
+
+  describe("selectPatternCenter", () => {
+    it("should return null when no pattern is loaded", () => {
+      // Clear the pattern
+      usePatternStore.setState({ pesData: null });
+
+      const center = selectPatternCenter(usePatternStore.getState());
+      expect(center).toBeNull();
+    });
+
+    it("should calculate center correctly for symmetric bounds", () => {
+      const state = usePatternStore.getState();
+      const center = selectPatternCenter(state);
+
+      expect(center).not.toBeNull();
+      expect(center!.x).toBe(0); // (minX + maxX) / 2 = (-100 + 100) / 2 = 0
+      expect(center!.y).toBe(0); // (minY + maxY) / 2 = (-50 + 50) / 2 = 0
+    });
+
+    it("should calculate center correctly for asymmetric bounds", () => {
+      const pesData = createMockPesData({
+        minX: 0,
+        maxX: 200,
+        minY: 0,
+        maxY: 100,
+      });
+      usePatternStore.setState({ pesData });
+
+      const state = usePatternStore.getState();
+      const center = selectPatternCenter(state);
+
+      expect(center).not.toBeNull();
+      expect(center!.x).toBe(100); // (0 + 200) / 2
+      expect(center!.y).toBe(50); // (0 + 100) / 2
+    });
+  });
+
+  describe("selectUploadedPatternCenter", () => {
+    it("should return null when no uploaded pattern", () => {
+      const state = usePatternStore.getState();
+      const center = selectUploadedPatternCenter(state);
+
+      expect(center).toBeNull();
+    });
+
+    it("should calculate center of uploaded pattern", () => {
+      const uploadedData = createMockPesData({
+        minX: 50,
+        maxX: 150,
+        minY: 25,
+        maxY: 75,
+      });
+      usePatternStore
+        .getState()
+        .setUploadedPattern(uploadedData, { x: 0, y: 0 });
+
+      const state = usePatternStore.getState();
+      const center = selectUploadedPatternCenter(state);
+
+      expect(center).not.toBeNull();
+      expect(center!.x).toBe(100); // (50 + 150) / 2
+      expect(center!.y).toBe(50); // (25 + 75) / 2
+    });
+  });
+
+  describe("selectRotatedBounds", () => {
+    it("should return original bounds when no rotation", () => {
+      const state = usePatternStore.getState();
+      const result = selectRotatedBounds(state);
+
+      expect(result).not.toBeNull();
+      expect(result!.bounds).toEqual({
+        minX: -100,
+        maxX: 100,
+        minY: -50,
+        maxY: 50,
+      });
+      expect(result!.center).toEqual({ x: 0, y: 0 });
+    });
+
+    it("should return null when no pattern", () => {
+      usePatternStore.setState({ pesData: null });
+      const state = usePatternStore.getState();
+      const result = selectRotatedBounds(state);
+
+      expect(result).toBeNull();
+    });
+
+    it("should calculate rotated bounds for 90 degree rotation", () => {
+      usePatternStore.getState().setPatternRotation(90);
+      const state = usePatternStore.getState();
+      const result = selectRotatedBounds(state);
+
+      expect(result).not.toBeNull();
+      // After 90° rotation, X and Y bounds should swap
+      expect(result!.bounds.minX).toBeCloseTo(-50, 0);
+      expect(result!.bounds.maxX).toBeCloseTo(50, 0);
+      expect(result!.bounds.minY).toBeCloseTo(-100, 0);
+      expect(result!.bounds.maxY).toBeCloseTo(100, 0);
+    });
+
+    it("should expand bounds for 45 degree rotation", () => {
+      usePatternStore.getState().setPatternRotation(45);
+      const state = usePatternStore.getState();
+      const result = selectRotatedBounds(state);
+
+      expect(result).not.toBeNull();
+      // After 45° rotation, bounds should expand
+      expect(Math.abs(result!.bounds.minX)).toBeGreaterThan(100);
+      expect(Math.abs(result!.bounds.minY)).toBeGreaterThan(50);
+    });
+  });
+
+  describe("selectRotationCenterShift", () => {
+    it("should return zero shift when no rotation", () => {
+      const state = usePatternStore.getState();
+      const rotatedBounds = state.pesData!.bounds;
+      const shift = selectRotationCenterShift(state, rotatedBounds);
+
+      expect(shift).toEqual({ x: 0, y: 0 });
+    });
+
+    it("should return null when no pattern", () => {
+      usePatternStore.setState({ pesData: null });
+      const state = usePatternStore.getState();
+      const shift = selectRotationCenterShift(state, {
+        minX: 0,
+        maxX: 100,
+        minY: 0,
+        maxY: 100,
+      });
+
+      expect(shift).toBeNull();
+    });
+
+    it("should calculate center shift for asymmetric pattern", () => {
+      const pesData = createMockPesData({
+        minX: 0,
+        maxX: 200,
+        minY: 0,
+        maxY: 100,
+      });
+      usePatternStore.setState({ pesData });
+      usePatternStore.getState().setPatternRotation(90);
+
+      const state = usePatternStore.getState();
+      const rotatedBounds = selectRotatedBounds(state)!.bounds;
+      const shift = selectRotationCenterShift(state, rotatedBounds);
+
+      expect(shift).not.toBeNull();
+      // Original center: (100, 50)
+      // After 90° rotation around center, new center should be slightly different
+      // due to the asymmetric bounds
+      expect(shift!.x).toBeCloseTo(0, 0);
+      expect(shift!.y).toBeCloseTo(0, 0);
+    });
+  });
+});
diff --git a/src/stores/usePatternStore.ts b/src/stores/usePatternStore.ts
index 610fe34..4a28fea 100644
--- a/src/stores/usePatternStore.ts
+++ b/src/stores/usePatternStore.ts
@@ -1,6 +1,9 @@
 import { create } from "zustand";
+import { useShallow } from "zustand/react/shallow";
 import type { PesPatternData } from "../formats/import/pesImporter";
 import { onPatternDeleted } from "./storeEvents";
+import { calculatePatternCenter } from "../components/PatternCanvas/patternCanvasHelpers";
+import { calculateRotatedBounds } from "../utils/rotationUtils";
 
 interface PatternState {
   // Original pattern (pre-upload)
@@ -29,6 +32,24 @@ interface PatternState {
   resetRotation: () => void;
 }
 
+// Computed value types
+export interface PatternCenter {
+  x: number;
+  y: number;
+}
+
+export interface PatternBounds {
+  minX: number;
+  maxX: number;
+  minY: number;
+  maxY: number;
+}
+
+export interface TransformedBounds {
+  bounds: PatternBounds;
+  center: PatternCenter;
+}
+
 export const usePatternStore = create<PatternState>((set) => ({
   // Initial state - original pattern
   pesData: null,
@@ -123,6 +144,88 @@ export const useUploadedPatternOffset = () =>
 export const usePatternRotation = () =>
   usePatternStore((state) => state.patternRotation);
 
+// Computed selectors (memoized by Zustand)
+// These provide single source of truth for derived state
+
+/**
+ * Select the geometric center of the pattern's bounds
+ */
+export const selectPatternCenter = (
+  state: PatternState,
+): PatternCenter | null => {
+  if (!state.pesData) return null;
+  return calculatePatternCenter(state.pesData.bounds);
+};
+
+/**
+ * Select the center of the uploaded pattern's bounds
+ */
+export const selectUploadedPatternCenter = (
+  state: PatternState,
+): PatternCenter | null => {
+  if (!state.uploadedPesData) return null;
+  return calculatePatternCenter(state.uploadedPesData.bounds);
+};
+
+/**
+ * Select the rotated bounds of the current pattern
+ * Returns original bounds if no rotation or no pattern
+ */
+export const selectRotatedBounds = (
+  state: PatternState,
+): TransformedBounds | null => {
+  if (!state.pesData) return null;
+
+  const bounds =
+    state.patternRotation && state.patternRotation !== 0
+      ? calculateRotatedBounds(state.pesData.bounds, state.patternRotation)
+      : state.pesData.bounds;
+
+  const center = calculatePatternCenter(bounds);
+
+  return { bounds, center };
+};
+
+/**
+ * Select the center shift caused by rotation
+ * This is used to adjust the offset when rotation is applied
+ * Returns null if no pattern or no rotation
+ */
+export const selectRotationCenterShift = (
+  state: PatternState,
+  rotatedBounds: PatternBounds,
+): { x: number; y: number } | null => {
+  if (!state.pesData) return null;
+  if (!state.patternRotation || state.patternRotation === 0)
+    return { x: 0, y: 0 };
+
+  const originalCenter = calculatePatternCenter(state.pesData.bounds);
+  const rotatedCenter = calculatePatternCenter(rotatedBounds);
+
+  return {
+    x: rotatedCenter.x - originalCenter.x,
+    y: rotatedCenter.y - originalCenter.y,
+  };
+};
+
+/**
+ * Hook to get pattern center (memoized with shallow comparison)
+ */
+export const usePatternCenter = () =>
+  usePatternStore(useShallow(selectPatternCenter));
+
+/**
+ * Hook to get uploaded pattern center (memoized with shallow comparison)
+ */
+export const useUploadedPatternCenter = () =>
+  usePatternStore(useShallow(selectUploadedPatternCenter));
+
+/**
+ * Hook to get rotated bounds (memoized with shallow comparison)
+ */
+export const useRotatedBounds = () =>
+  usePatternStore(useShallow(selectRotatedBounds));
+
 // Subscribe to pattern deleted event.
 // This subscription is intended to persist for the lifetime of the application,
 // so the unsubscribe function returned by `onPatternDeleted` is intentionally