diff --git a/apps/calculation/calculation.cpp b/apps/calculation/calculation.cpp
index 504e74d1e..fe1d36de1 100644
--- a/apps/calculation/calculation.cpp
+++ b/apps/calculation/calculation.cpp
@@ -33,6 +33,13 @@ Calculation * Calculation::next() const {
   return reinterpret_cast<Calculation *>(const_cast<char *>(result));
 }
 
+void Calculation::tidy() {
+  /* Reset height memoization (the complex format could have changed when
+   * re-entering Calculation app which would impact the heights). */
+  m_height = -1;
+  m_expandedHeight = -1;
+}
+
 const char * Calculation::approximateOutputText() const {
   const char * exactOutput = exactOutputText();
   return exactOutput + strlen(exactOutput) + 1;
diff --git a/apps/calculation/calculation.h b/apps/calculation/calculation.h
index c9d23c9f1..9e5b9b85a 100644
--- a/apps/calculation/calculation.h
+++ b/apps/calculation/calculation.h
@@ -50,6 +50,8 @@ public:
   bool operator==(const Calculation& c);
   Calculation * next() const;
 
+  void tidy();
+
   // Texts
   const char * inputText() const { return m_inputText; }
   const char * exactOutputText() const { return m_inputText + strlen(m_inputText) + 1; }
diff --git a/apps/calculation/calculation_store.cpp b/apps/calculation/calculation_store.cpp
index be2148b27..472889d66 100644
--- a/apps/calculation/calculation_store.cpp
+++ b/apps/calculation/calculation_store.cpp
@@ -141,6 +141,13 @@ void CalculationStore::deleteAll() {
   resetMemoizedModelsAfterCalculationIndex(-1);
 }
 
+void CalculationStore::tidy() {
+  resetMemoizedModelsAfterCalculationIndex(-1);
+  for (Calculation * c : *this) {
+    c->tidy();
+  }
+}
+
 Expression CalculationStore::ansExpression(Context * context) {
   if (numberOfCalculations() == 0) {
     return Rational::Builder(0);
diff --git a/apps/calculation/calculation_store.h b/apps/calculation/calculation_store.h
index c3f8cf876..b21685fd8 100644
--- a/apps/calculation/calculation_store.h
+++ b/apps/calculation/calculation_store.h
@@ -32,7 +32,7 @@ public:
   void deleteAll();
   int numberOfCalculations() const { return m_numberOfCalculations; }
   Poincare::Expression ansExpression(Poincare::Context * context);
-  void tidy() { resetMemoizedModelsAfterCalculationIndex(-1); }
+  void tidy();
 private:
   static constexpr int k_bufferSize = 10 * 3 * Constant::MaxSerializedExpressionSize;