diff --git a/Calc/CalculatorViewModel.swift b/Calc/CalculatorViewModel.swift
index c88202e..7d1215a 100644
--- a/Calc/CalculatorViewModel.swift
+++ b/Calc/CalculatorViewModel.swift
@@ -23,6 +23,7 @@ final class CalculatorViewModel: ObservableObject {
     private let engine = CalculatorEngine()
     private let historyKey = "calc.history"
     private var didJustEvaluate = false
+    private var isShowingPlaceholder = true
     private let displayGroupingSeparator = Locale.current.groupingSeparator ?? ","
 
     init() {
@@ -38,7 +39,7 @@ final class CalculatorViewModel: ObservableObject {
     }
 
     var canCopyDisplayValue: Bool {
-        !displayValueToCopy.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
+        !isShowingPlaceholder && !displayValueToCopy.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
     }
 
     func input(_ token: String) {
@@ -88,6 +89,7 @@ final class CalculatorViewModel: ObservableObject {
         expression = "0"
         errorMessage = nil
         didJustEvaluate = false
+        isShowingPlaceholder = true
     }
 
     func deleteBackward() {
@@ -97,9 +99,15 @@ final class CalculatorViewModel: ObservableObject {
         expression = expression.isEmpty ? "0" : expression
         errorMessage = nil
         didJustEvaluate = false
+        isShowingPlaceholder = expression == "0"
     }
 
     func evaluate() {
+        guard !isShowingPlaceholder else {
+            errorMessage = nil
+            return
+        }
+
         do {
             let result = try engine.evaluate(expression)
             let formattedResult = engine.format(result)
@@ -119,6 +127,7 @@ final class CalculatorViewModel: ObservableObject {
             expression = engine.expressionString(result)
             errorMessage = nil
             didJustEvaluate = true
+            isShowingPlaceholder = false
         } catch let error as CalculatorError {
             errorMessage = error.errorDescription
             didJustEvaluate = false
@@ -132,6 +141,7 @@ final class CalculatorViewModel: ObservableObject {
         expression = record.result
         errorMessage = nil
         didJustEvaluate = true
+        isShowingPlaceholder = false
     }
 
     func clearHistory() {
@@ -201,10 +211,11 @@ final class CalculatorViewModel: ObservableObject {
             expression = digit
             didJustEvaluate = false
             errorMessage = nil
+            isShowingPlaceholder = false
             return
         }
 
-        if expression == "0" {
+        if isShowingPlaceholder || expression == "0" {
             expression = digit
         } else if shouldInsertMultiplicationBeforeNumber {
             expression += "*\(digit)"
@@ -213,6 +224,7 @@ final class CalculatorViewModel: ObservableObject {
         }
 
         errorMessage = nil
+        isShowingPlaceholder = false
     }
 
     private func appendDecimalPoint() {
@@ -220,6 +232,7 @@ final class CalculatorViewModel: ObservableObject {
             expression = "0."
             didJustEvaluate = false
             errorMessage = nil
+            isShowingPlaceholder = false
             return
         }
 
@@ -238,6 +251,7 @@ final class CalculatorViewModel: ObservableObject {
         }
 
         errorMessage = nil
+        isShowingPlaceholder = false
     }
 
     private func appendOperator(_ `operator`: String) {
@@ -245,9 +259,11 @@ final class CalculatorViewModel: ObservableObject {
             didJustEvaluate = false
         }
 
-        if expression == "0" && `operator` == "-" {
+        if isShowingPlaceholder {
+            guard `operator` == "-" else { return }
             expression = "-"
             errorMessage = nil
+            isShowingPlaceholder = false
             return
         }
 
@@ -276,6 +292,7 @@ final class CalculatorViewModel: ObservableObject {
         }
 
         errorMessage = nil
+        isShowingPlaceholder = false
     }
 
     private func appendLeftParenthesis() {
@@ -283,10 +300,11 @@ final class CalculatorViewModel: ObservableObject {
             expression = "("
             didJustEvaluate = false
             errorMessage = nil
+            isShowingPlaceholder = false
             return
         }
 
-        if expression == "0" {
+        if isShowingPlaceholder || expression == "0" {
             expression = "("
         } else if let lastCharacter {
             if lastCharacter.isLetter {
@@ -307,6 +325,7 @@ final class CalculatorViewModel: ObservableObject {
         }
 
         errorMessage = nil
+        isShowingPlaceholder = false
     }
 
     private func appendRightParenthesis() {
@@ -315,6 +334,7 @@ final class CalculatorViewModel: ObservableObject {
 
         expression.append(")")
         errorMessage = nil
+        isShowingPlaceholder = false
     }
 
     private func currentNumberSegment() -> String {
@@ -394,7 +414,7 @@ final class CalculatorViewModel: ObservableObject {
         if didJustEvaluate {
             expression = character
             didJustEvaluate = false
-        } else if expression == "0" {
+        } else if isShowingPlaceholder || expression == "0" {
             expression = character
         } else if shouldInsertMultiplicationBeforeValue {
             expression += "*\(character)"
@@ -403,6 +423,7 @@ final class CalculatorViewModel: ObservableObject {
         }
 
         errorMessage = nil
+        isShowingPlaceholder = false
     }
 
     private func appendScientificFunction(_ function: String) {
@@ -411,7 +432,7 @@ final class CalculatorViewModel: ObservableObject {
         if didJustEvaluate {
             expression = functionToken
             didJustEvaluate = false
-        } else if expression == "0" {
+        } else if isShowingPlaceholder || expression == "0" {
             expression = functionToken
         } else if shouldInsertMultiplicationBeforeValue {
             expression += "*\(functionToken)"
@@ -420,13 +441,14 @@ final class CalculatorViewModel: ObservableObject {
         }
 
         errorMessage = nil
+        isShowingPlaceholder = false
     }
 
     private func appendConstant(_ constant: String) {
         if didJustEvaluate {
             expression = constant
             didJustEvaluate = false
-        } else if expression == "0" {
+        } else if isShowingPlaceholder || expression == "0" {
             expression = constant
         } else if shouldInsertMultiplicationBeforeValue {
             expression += "*\(constant)"
@@ -435,6 +457,7 @@ final class CalculatorViewModel: ObservableObject {
         }
 
         errorMessage = nil
+        isShowingPlaceholder = false
     }
 
     private func formatExpressionForDisplay(_ expression: String) -> String {
diff --git a/CalcTests/CalculatorEngineTests.swift b/CalcTests/CalculatorEngineTests.swift
index 7adf049..d7b0074 100644
--- a/CalcTests/CalculatorEngineTests.swift
+++ b/CalcTests/CalculatorEngineTests.swift
@@ -120,6 +120,30 @@ final class CalculatorViewModelTests: XCTestCase {
         XCTAssertTrue(viewModel.canCopyDisplayValue)
     }
 
+    func testPlaceholderZeroDoesNotEvaluate() {
+        let viewModel = CalculatorViewModel()
+        let initialHistoryCount = viewModel.history.count
+
+        viewModel.evaluate()
+
+        XCTAssertEqual(viewModel.expression, "0")
+        XCTAssertEqual(viewModel.history.count, initialHistoryCount)
+        XCTAssertNil(viewModel.errorMessage)
+    }
+
+    func testEnteredZeroStillEvaluates() {
+        let viewModel = CalculatorViewModel()
+        let initialHistoryCount = viewModel.history.count
+
+        viewModel.input("0")
+        viewModel.evaluate()
+
+        XCTAssertEqual(viewModel.expression, "0")
+        XCTAssertEqual(viewModel.history.first?.result, "0")
+        XCTAssertEqual(viewModel.history.count, initialHistoryCount + 1)
+        XCTAssertNil(viewModel.errorMessage)
+    }
+
     func testExpressionDisplayFormatsTypedLargeNumber() {
         let viewModel = CalculatorViewModel()