diff --git a/src/hooks/useTransactions.ts b/src/hooks/useTransactions.ts
index 2be514d..2e0e43d 100644
--- a/src/hooks/useTransactions.ts
+++ b/src/hooks/useTransactions.ts
@@ -1,22 +1,29 @@
 
 import { useState, useEffect } from 'react';
 import { Transaction } from '@/components/TransactionCard';
-import { supabase } from '@/lib/supabase';
 import { useAuth } from '@/contexts/auth/AuthProvider';
 import { toast } from '@/hooks/useToast.wrapper';
 import { isSyncEnabled } from '@/utils/syncUtils';
+import { MONTHS_KR, getCurrentMonth, getPrevMonth, getNextMonth } from '@/utils/dateUtils';
+import { 
+  loadTransactionsFromStorage, 
+  createSampleTransactions, 
+  saveTransactionsToStorage, 
+  loadBudgetFromStorage 
+} from '@/utils/storageUtils';
+import { 
+  filterTransactionsByMonth, 
+  filterTransactionsByQuery, 
+  calculateTotalExpenses
+} from '@/utils/transactionUtils';
+import { 
+  syncTransactionsWithSupabase, 
+  updateTransactionInSupabase, 
+  deleteTransactionFromSupabase 
+} from '@/utils/supabaseTransactionUtils';
 
-// 월 이름 정의
-export const MONTHS_KR = [
-  '1월', '2월', '3월', '4월', '5월', '6월', 
-  '7월', '8월', '9월', '10월', '11월', '12월'
-];
-
-// 현재 월 가져오기
-const getCurrentMonth = () => {
-  const now = new Date();
-  return MONTHS_KR[now.getMonth()];
-};
+// 월 이름 재노출
+export { MONTHS_KR };
 
 export const useTransactions = () => {
   const [transactions, setTransactions] = useState<Transaction[]>([]);
@@ -30,21 +37,11 @@ export const useTransactions = () => {
 
   // 월 변경 처리
   const handlePrevMonth = () => {
-    const currentIndex = MONTHS_KR.indexOf(selectedMonth);
-    if (currentIndex > 0) {
-      setSelectedMonth(MONTHS_KR[currentIndex - 1]);
-    } else {
-      setSelectedMonth(MONTHS_KR[MONTHS_KR.length - 1]);
-    }
+    setSelectedMonth(getPrevMonth(selectedMonth));
   };
 
   const handleNextMonth = () => {
-    const currentIndex = MONTHS_KR.indexOf(selectedMonth);
-    if (currentIndex < MONTHS_KR.length - 1) {
-      setSelectedMonth(MONTHS_KR[currentIndex + 1]);
-    } else {
-      setSelectedMonth(MONTHS_KR[0]);
-    }
+    setSelectedMonth(getNextMonth(selectedMonth));
   };
 
   // 트랜잭션 로드
@@ -54,60 +51,20 @@ export const useTransactions = () => {
     
     try {
       // 로컬 스토리지에서 트랜잭션 데이터 가져오기
-      const localData = localStorage.getItem('transactions');
+      const localData = loadTransactionsFromStorage();
       
-      if (localData) {
-        const parsedData = JSON.parse(localData) as Transaction[];
-        setTransactions(parsedData);
+      if (localData.length > 0) {
+        setTransactions(localData);
       } else {
-        // 샘플 데이터 설정 (실제 앱에서는 빈 배열로 시작할 수 있음)
-        const sampleData: Transaction[] = [{
-          id: '1',
-          title: '식료품 구매',
-          amount: 25000,
-          date: `${selectedMonth} 25일, 12:30 PM`,
-          category: '식비',
-          type: 'expense'
-        }, {
-          id: '2',
-          title: '주유소',
-          amount: 50000,
-          date: `${selectedMonth} 24일, 3:45 PM`,
-          category: '교통비',
-          type: 'expense'
-        }, {
-          id: '4',
-          title: '생필품 구매',
-          amount: 35000,
-          date: `${selectedMonth} 18일, 6:00 AM`,
-          category: '생활비',
-          type: 'expense'
-        }, {
-          id: '5',
-          title: '월세',
-          amount: 650000,
-          date: `${selectedMonth} 15일, 10:00 AM`,
-          category: '생활비',
-          type: 'expense'
-        }, {
-          id: '6',
-          title: '식당',
-          amount: 15500,
-          date: `${selectedMonth} 12일, 2:15 PM`,
-          category: '식비',
-          type: 'expense'
-        }];
-        
+        // 샘플 데이터 설정
+        const sampleData = createSampleTransactions(selectedMonth);
         setTransactions(sampleData);
-        localStorage.setItem('transactions', JSON.stringify(sampleData));
+        saveTransactionsToStorage(sampleData);
       }
 
       // 예산 가져오기
-      const budgetData = localStorage.getItem('budget');
-      if (budgetData) {
-        const parsedBudget = JSON.parse(budgetData);
-        setTotalBudget(parsedBudget.total || 1000000);
-      }
+      const budget = loadBudgetFromStorage();
+      setTotalBudget(budget);
     } catch (err) {
       console.error('트랜잭션 로드 중 오류:', err);
       setError('데이터를 불러오는 중 문제가 발생했습니다.');
@@ -124,17 +81,11 @@ export const useTransactions = () => {
   // 필터 적용
   useEffect(() => {
     // 1. 월별 필터링
-    let filtered = transactions.filter(transaction => 
-      transaction.date.includes(selectedMonth) && transaction.type === 'expense'
-    );
+    let filtered = filterTransactionsByMonth(transactions, selectedMonth);
     
-    // 2. 검색어 필터링 (검색어가 있는 경우)
+    // 2. 검색어 필터링
     if (searchQuery.trim()) {
-      const query = searchQuery.toLowerCase().trim();
-      filtered = filtered.filter(transaction => 
-        transaction.title.toLowerCase().includes(query) || 
-        transaction.category.toLowerCase().includes(query)
-      );
+      filtered = filterTransactionsByQuery(filtered, searchQuery);
     }
     
     setFilteredTransactions(filtered);
@@ -146,44 +97,11 @@ export const useTransactions = () => {
     
     // Supabase 동기화 (로그인 상태인 경우)
     const syncWithSupabase = async () => {
-      if (user && isSyncEnabled()) {
-        try {
-          const { data, error } = await supabase
-            .from('transactions')
-            .select('*')
-            .eq('user_id', user.id);
-            
-          if (error) throw error;
-          
-          if (data && data.length > 0) {
-            // Supabase 데이터 로컬 형식으로 변환
-            const supabaseTransactions = data.map(t => ({
-              id: t.transaction_id || t.id,
-              title: t.title,
-              amount: t.amount,
-              date: t.date,
-              category: t.category,
-              type: t.type
-            }));
-            
-            // 로컬 데이터와 병합 (중복 ID 제거)
-            const mergedTransactions = [...transactions];
-            
-            supabaseTransactions.forEach(newTx => {
-              const existingIndex = mergedTransactions.findIndex(t => t.id === newTx.id);
-              if (existingIndex >= 0) {
-                mergedTransactions[existingIndex] = newTx;
-              } else {
-                mergedTransactions.push(newTx);
-              }
-            });
-            
-            setTransactions(mergedTransactions);
-            localStorage.setItem('transactions', JSON.stringify(mergedTransactions));
-          }
-        } catch (err) {
-          console.error('Supabase 동기화 오류:', err);
-          // 동기화 실패해도 기존 로컬 데이터는 유지
+      if (user) {
+        const syncedTransactions = await syncTransactionsWithSupabase(user, transactions);
+        if (syncedTransactions !== transactions) {
+          setTransactions(syncedTransactions);
+          saveTransactionsToStorage(syncedTransactions);
         }
       }
     };
@@ -198,26 +116,10 @@ export const useTransactions = () => {
     );
     
     setTransactions(updatedTransactions);
-    localStorage.setItem('transactions', JSON.stringify(updatedTransactions));
+    saveTransactionsToStorage(updatedTransactions);
     
-    // Supabase에도 업데이트 (로그인 및 동기화 활성화된 경우)
-    if (user && isSyncEnabled()) {
-      supabase.from('transactions')
-        .upsert({
-          user_id: user.id,
-          title: updatedTransaction.title,
-          amount: updatedTransaction.amount,
-          date: updatedTransaction.date,
-          category: updatedTransaction.category,
-          type: updatedTransaction.type,
-          transaction_id: updatedTransaction.id
-        })
-        .then(({ error }) => {
-          if (error) {
-            console.error('Supabase 업데이트 오류:', error);
-          }
-        });
-    }
+    // Supabase에도 업데이트
+    updateTransactionInSupabase(user, updatedTransaction);
     
     toast({
       title: "지출이 수정되었습니다",
@@ -230,19 +132,10 @@ export const useTransactions = () => {
     const updatedTransactions = transactions.filter(transaction => transaction.id !== id);
     
     setTransactions(updatedTransactions);
-    localStorage.setItem('transactions', JSON.stringify(updatedTransactions));
+    saveTransactionsToStorage(updatedTransactions);
     
-    // Supabase에서도 삭제 (로그인 및 동기화 활성화된 경우)
-    if (user && isSyncEnabled()) {
-      supabase.from('transactions')
-        .delete()
-        .eq('transaction_id', id)
-        .then(({ error }) => {
-          if (error) {
-            console.error('Supabase 삭제 오류:', error);
-          }
-        });
-    }
+    // Supabase에서도 삭제
+    deleteTransactionFromSupabase(user, id);
     
     toast({
       title: "지출이 삭제되었습니다",
@@ -262,7 +155,7 @@ export const useTransactions = () => {
     handleNextMonth,
     updateTransaction,
     deleteTransaction,
-    totalExpenses: filteredTransactions.reduce((sum, t) => sum + t.amount, 0),
+    totalExpenses: calculateTotalExpenses(filteredTransactions),
     refreshTransactions: loadTransactions
   };
 };
diff --git a/src/utils/dateUtils.ts b/src/utils/dateUtils.ts
new file mode 100644
index 0000000..423b603
--- /dev/null
+++ b/src/utils/dateUtils.ts
@@ -0,0 +1,32 @@
+
+// 월 이름 정의
+export const MONTHS_KR = [
+  '1월', '2월', '3월', '4월', '5월', '6월', 
+  '7월', '8월', '9월', '10월', '11월', '12월'
+];
+
+// 현재 월 가져오기
+export const getCurrentMonth = () => {
+  const now = new Date();
+  return MONTHS_KR[now.getMonth()];
+};
+
+// 이전 달 가져오기
+export const getPrevMonth = (currentMonth: string) => {
+  const currentIndex = MONTHS_KR.indexOf(currentMonth);
+  if (currentIndex > 0) {
+    return MONTHS_KR[currentIndex - 1];
+  } else {
+    return MONTHS_KR[MONTHS_KR.length - 1];
+  }
+};
+
+// 다음 달 가져오기
+export const getNextMonth = (currentMonth: string) => {
+  const currentIndex = MONTHS_KR.indexOf(currentMonth);
+  if (currentIndex < MONTHS_KR.length - 1) {
+    return MONTHS_KR[currentIndex + 1];
+  } else {
+    return MONTHS_KR[0];
+  }
+};
diff --git a/src/utils/storageUtils.ts b/src/utils/storageUtils.ts
new file mode 100644
index 0000000..5458484
--- /dev/null
+++ b/src/utils/storageUtils.ts
@@ -0,0 +1,66 @@
+
+import { Transaction } from '@/components/TransactionCard';
+
+// 트랜잭션 데이터 불러오기
+export const loadTransactionsFromStorage = (): Transaction[] => {
+  const localData = localStorage.getItem('transactions');
+  if (localData) {
+    return JSON.parse(localData) as Transaction[];
+  }
+  return [];
+};
+
+// 기본 샘플 데이터 생성
+export const createSampleTransactions = (selectedMonth: string): Transaction[] => {
+  return [{
+    id: '1',
+    title: '식료품 구매',
+    amount: 25000,
+    date: `${selectedMonth} 25일, 12:30 PM`,
+    category: '식비',
+    type: 'expense'
+  }, {
+    id: '2',
+    title: '주유소',
+    amount: 50000,
+    date: `${selectedMonth} 24일, 3:45 PM`,
+    category: '교통비',
+    type: 'expense'
+  }, {
+    id: '4',
+    title: '생필품 구매',
+    amount: 35000,
+    date: `${selectedMonth} 18일, 6:00 AM`,
+    category: '생활비',
+    type: 'expense'
+  }, {
+    id: '5',
+    title: '월세',
+    amount: 650000,
+    date: `${selectedMonth} 15일, 10:00 AM`,
+    category: '생활비',
+    type: 'expense'
+  }, {
+    id: '6',
+    title: '식당',
+    amount: 15500,
+    date: `${selectedMonth} 12일, 2:15 PM`,
+    category: '식비',
+    type: 'expense'
+  }];
+};
+
+// 트랜잭션 데이터 저장하기
+export const saveTransactionsToStorage = (transactions: Transaction[]): void => {
+  localStorage.setItem('transactions', JSON.stringify(transactions));
+};
+
+// 예산 불러오기
+export const loadBudgetFromStorage = (): number => {
+  const budgetData = localStorage.getItem('budget');
+  if (budgetData) {
+    const parsedBudget = JSON.parse(budgetData);
+    return parsedBudget.total || 1000000;
+  }
+  return 1000000; // 기본 예산
+};
diff --git a/src/utils/supabaseTransactionUtils.ts b/src/utils/supabaseTransactionUtils.ts
new file mode 100644
index 0000000..f2f359d
--- /dev/null
+++ b/src/utils/supabaseTransactionUtils.ts
@@ -0,0 +1,91 @@
+
+import { supabase } from '@/lib/supabase';
+import { Transaction } from '@/components/TransactionCard';
+import { isSyncEnabled } from '@/utils/syncUtils';
+import { toast } from '@/hooks/useToast.wrapper';
+
+// Supabase와 거래 데이터 동기화
+export const syncTransactionsWithSupabase = async (
+  user: any, 
+  transactions: Transaction[]
+): Promise<Transaction[]> => {
+  if (!user || !isSyncEnabled()) return transactions;
+  
+  try {
+    const { data, error } = await supabase
+      .from('transactions')
+      .select('*')
+      .eq('user_id', user.id);
+      
+    if (error) throw error;
+    
+    if (data && data.length > 0) {
+      // Supabase 데이터 로컬 형식으로 변환
+      const supabaseTransactions = data.map(t => ({
+        id: t.transaction_id || t.id,
+        title: t.title,
+        amount: t.amount,
+        date: t.date,
+        category: t.category,
+        type: t.type
+      }));
+      
+      // 로컬 데이터와 병합 (중복 ID 제거)
+      const mergedTransactions = [...transactions];
+      
+      supabaseTransactions.forEach(newTx => {
+        const existingIndex = mergedTransactions.findIndex(t => t.id === newTx.id);
+        if (existingIndex >= 0) {
+          mergedTransactions[existingIndex] = newTx;
+        } else {
+          mergedTransactions.push(newTx);
+        }
+      });
+      
+      return mergedTransactions;
+    }
+  } catch (err) {
+    console.error('Supabase 동기화 오류:', err);
+  }
+  
+  return transactions;
+};
+
+// Supabase에 트랜잭션 업데이트
+export const updateTransactionInSupabase = async (
+  user: any,
+  transaction: Transaction
+): Promise<void> => {
+  if (!user || !isSyncEnabled()) return;
+  
+  try {
+    await supabase.from('transactions')
+      .upsert({
+        user_id: user.id,
+        title: transaction.title,
+        amount: transaction.amount,
+        date: transaction.date,
+        category: transaction.category,
+        type: transaction.type,
+        transaction_id: transaction.id
+      });
+  } catch (error) {
+    console.error('Supabase 업데이트 오류:', error);
+  }
+};
+
+// Supabase에서 트랜잭션 삭제
+export const deleteTransactionFromSupabase = async (
+  user: any,
+  transactionId: string
+): Promise<void> => {
+  if (!user || !isSyncEnabled()) return;
+  
+  try {
+    await supabase.from('transactions')
+      .delete()
+      .eq('transaction_id', transactionId);
+  } catch (error) {
+    console.error('Supabase 삭제 오류:', error);
+  }
+};
diff --git a/src/utils/transactionUtils.ts b/src/utils/transactionUtils.ts
new file mode 100644
index 0000000..14a018b
--- /dev/null
+++ b/src/utils/transactionUtils.ts
@@ -0,0 +1,31 @@
+
+import { Transaction } from '@/components/TransactionCard';
+
+// 월별로 트랜잭션 필터링
+export const filterTransactionsByMonth = (
+  transactions: Transaction[], 
+  selectedMonth: string
+): Transaction[] => {
+  return transactions.filter(transaction => 
+    transaction.date.includes(selectedMonth) && transaction.type === 'expense'
+  );
+};
+
+// 검색어로 트랜잭션 필터링
+export const filterTransactionsByQuery = (
+  transactions: Transaction[],
+  searchQuery: string
+): Transaction[] => {
+  if (!searchQuery.trim()) return transactions;
+  
+  const query = searchQuery.toLowerCase().trim();
+  return transactions.filter(transaction => 
+    transaction.title.toLowerCase().includes(query) || 
+    transaction.category.toLowerCase().includes(query)
+  );
+};
+
+// 총 지출 금액 계산
+export const calculateTotalExpenses = (transactions: Transaction[]): number => {
+  return transactions.reduce((sum, t) => sum + t.amount, 0);
+};