diff --git a/packages/react-native-mmkv/cpp/HybridMMKV.cpp b/packages/react-native-mmkv/cpp/HybridMMKV.cpp
index 1086ea5c..13d1a24b 100644
--- a/packages/react-native-mmkv/cpp/HybridMMKV.cpp
+++ b/packages/react-native-mmkv/cpp/HybridMMKV.cpp
@@ -82,6 +82,10 @@ double HybridMMKV::getByteSize() {
   return instance->actualSize();
 }
 
+size_t HybridMMKV::getExternalMemorySize() noexcept {
+  return instance != nullptr ? instance->actualSize() : 0;
+}
+
 bool HybridMMKV::getIsReadOnly() {
   return instance->isReadOnly();
 }
diff --git a/packages/react-native-mmkv/cpp/HybridMMKV.hpp b/packages/react-native-mmkv/cpp/HybridMMKV.hpp
index 4c8053a1..e2d18ec4 100644
--- a/packages/react-native-mmkv/cpp/HybridMMKV.hpp
+++ b/packages/react-native-mmkv/cpp/HybridMMKV.hpp
@@ -44,6 +44,9 @@ class HybridMMKV final : public HybridMMKVSpec {
   Listener addOnValueChangedListener(const std::function<void(const std::string& /* key */)>& onValueChanged) override;
   double importAllFrom(const std::shared_ptr<HybridMMKVSpec>& other) override;
 
+protected:
+  size_t getExternalMemorySize() noexcept override;
+
 private:
   static MMKVMode getMMKVMode(const Configuration& config);