diff --git a/src/components/common/input/CalcInput.jsx b/src/components/common/input/CalcInput.jsx
index 9cfddfd4..e8a97b93 100644
--- a/src/components/common/input/CalcInput.jsx
+++ b/src/components/common/input/CalcInput.jsx
@@ -63,6 +63,33 @@ export const CalculatorInput = forwardRef(
       const calculator = calculatorRef.current
       let newDisplayValue = ''
 
+      // 블록 지정(Selection) 확인 및 처리
+      if (inputRef.current) {
+        const { selectionStart, selectionEnd } = inputRef.current
+        // 텍스트 전체 또는 일부가 블록 지정된 경우
+        if (selectionStart !== null && selectionEnd !== null && selectionStart !== selectionEnd) {
+          // 연산 중이 아닐 때만 전체 초기화 후 입력 처리 (계산기 모드 유지를 위해)
+          if (!hasOperation) {
+            calculator.currentOperand = num.toString()
+            calculator.previousOperand = ''
+            calculator.operation = undefined
+            calculator.shouldResetDisplay = false
+
+            newDisplayValue = calculator.currentOperand
+            setDisplayValue(newDisplayValue)
+            onChange(newDisplayValue)
+
+            requestAnimationFrame(() => {
+              if (inputRef.current) {
+                inputRef.current.focus()
+                inputRef.current.setSelectionRange(newDisplayValue.length, newDisplayValue.length)
+              }
+            })
+            return // 블록 처리 로직 완료 후 종료
+          }
+        }
+      }
+
       // maxLength 체크
       if (maxLength > 0) {
         const currentLength = (calculator.currentOperand || '').length + (calculator.previousOperand || '').length + (calculator.operation || '').length