diff --git a/src/include/storage/index/b_plus_tree.h b/src/include/storage/index/b_plus_tree.h
index bc1c31b27..ad3036d05 100644
--- a/src/include/storage/index/b_plus_tree.h
+++ b/src/include/storage/index/b_plus_tree.h
@@ -66,8 +66,8 @@ class BPlusTree {
 
  public:
   explicit BPlusTree(std::string name, page_id_t header_page_id, BufferPoolManager *buffer_pool_manager,
-                     const KeyComparator &comparator, int leaf_max_size = LEAF_PAGE_SIZE,
-                     int internal_max_size = INTERNAL_PAGE_SIZE);
+                     const KeyComparator &comparator, int leaf_max_size = LeafPage::LEAF_PAGE_SIZE,
+                     int internal_max_size = InternalPage::INTERNAL_PAGE_SIZE);
 
   // Returns true if this B+ tree has no keys and values.
   auto IsEmpty() const -> bool;
diff --git a/src/include/storage/index/index_iterator.h b/src/include/storage/index/index_iterator.h
index 7618823e1..cba7478d4 100644
--- a/src/include/storage/index/index_iterator.h
+++ b/src/include/storage/index/index_iterator.h
@@ -21,6 +21,9 @@ namespace bustub {
 
 INDEX_TEMPLATE_ARGUMENTS
 class IndexIterator {
+  using LeafPage = BPlusTreeLeafPage<KeyType, ValueType, KeyComparator>;
+  using MappingType = typename LeafPage::MappingType;
+
  public:
   // you may define your own constructor based on your member variables
   IndexIterator();
diff --git a/src/include/storage/page/b_plus_tree_internal_page.h b/src/include/storage/page/b_plus_tree_internal_page.h
index c26a5a86a..517f23a61 100644
--- a/src/include/storage/page/b_plus_tree_internal_page.h
+++ b/src/include/storage/page/b_plus_tree_internal_page.h
@@ -18,8 +18,9 @@
 namespace bustub {
 
 #define B_PLUS_TREE_INTERNAL_PAGE_TYPE BPlusTreeInternalPage<KeyType, ValueType, KeyComparator>
-#define INTERNAL_PAGE_HEADER_SIZE 12
-#define INTERNAL_PAGE_SIZE ((BUSTUB_PAGE_SIZE - INTERNAL_PAGE_HEADER_SIZE) / (sizeof(MappingType)))
+
+constexpr const auto INTERNAL_PAGE_HEADER_SIZE = 12;
+
 /**
  * Store n indexed keys and n+1 child pointers (page_id) within internal page.
  * Pointer PAGE_ID(i) points to a subtree in which all keys K satisfy:
@@ -36,6 +37,11 @@ namespace bustub {
 INDEX_TEMPLATE_ARGUMENTS
 class BPlusTreeInternalPage : public BPlusTreePage {
  public:
+  using MappingType = MappingType_<KeyType, ValueType>;
+
+  constexpr static const auto INTERNAL_PAGE_SIZE =
+      (BUSTUB_PAGE_SIZE - INTERNAL_PAGE_HEADER_SIZE) / (sizeof(MappingType));
+
   // Deleted to disallow initialization
   BPlusTreeInternalPage() = delete;
   BPlusTreeInternalPage(const BPlusTreeInternalPage &other) = delete;
diff --git a/src/include/storage/page/b_plus_tree_leaf_page.h b/src/include/storage/page/b_plus_tree_leaf_page.h
index cf7a294b7..48d514790 100644
--- a/src/include/storage/page/b_plus_tree_leaf_page.h
+++ b/src/include/storage/page/b_plus_tree_leaf_page.h
@@ -19,8 +19,8 @@
 namespace bustub {
 
 #define B_PLUS_TREE_LEAF_PAGE_TYPE BPlusTreeLeafPage<KeyType, ValueType, KeyComparator>
-#define LEAF_PAGE_HEADER_SIZE 16
-#define LEAF_PAGE_SIZE ((BUSTUB_PAGE_SIZE - LEAF_PAGE_HEADER_SIZE) / sizeof(MappingType))
+
+constexpr const auto LEAF_PAGE_HEADER_SIZE = 16;
 
 /**
  * Store indexed key and record id(record id = page id combined with slot id,
@@ -43,6 +43,10 @@ namespace bustub {
 INDEX_TEMPLATE_ARGUMENTS
 class BPlusTreeLeafPage : public BPlusTreePage {
  public:
+  using MappingType = MappingType_<KeyType, ValueType>;
+
+  constexpr static const auto LEAF_PAGE_SIZE = ((BUSTUB_PAGE_SIZE - LEAF_PAGE_HEADER_SIZE) / sizeof(MappingType));
+
   // Delete all constructor / destructor to ensure memory safety
   BPlusTreeLeafPage() = delete;
   BPlusTreeLeafPage(const BPlusTreeLeafPage &other) = delete;
diff --git a/src/include/storage/page/b_plus_tree_page.h b/src/include/storage/page/b_plus_tree_page.h
index 48914421a..d0a8dce54 100644
--- a/src/include/storage/page/b_plus_tree_page.h
+++ b/src/include/storage/page/b_plus_tree_page.h
@@ -14,13 +14,15 @@
 #include <climits>
 #include <cstdlib>
 #include <string>
+#include <utility>
 
 #include "buffer/buffer_pool_manager.h"
 #include "storage/index/generic_key.h"
 
 namespace bustub {
 
-#define MappingType std::pair<KeyType, ValueType>
+template <typename KeyType, typename ValueType>
+using MappingType_ = std::pair<KeyType, ValueType>;
 
 #define INDEX_TEMPLATE_ARGUMENTS template <typename KeyType, typename ValueType, typename KeyComparator>
 
diff --git a/src/storage/page/b_plus_tree_leaf_page.cpp b/src/storage/page/b_plus_tree_leaf_page.cpp
index 3b325d721..219978b7b 100644
--- a/src/storage/page/b_plus_tree_leaf_page.cpp
+++ b/src/storage/page/b_plus_tree_leaf_page.cpp
@@ -14,6 +14,7 @@
 #include "common/exception.h"
 #include "common/rid.h"
 #include "storage/page/b_plus_tree_leaf_page.h"
+#include "storage/page/b_plus_tree_page.h"
 
 namespace bustub {