diff --git a/Core/Config.cpp b/Core/Config.cpp
index 95daf8a869..8233a7fec2 100644
--- a/Core/Config.cpp
+++ b/Core/Config.cpp
@@ -1030,6 +1030,7 @@ static ConfigSetting systemParamSettings[] = {
 	ConfigSetting("WlanPowerSave", &g_Config.bWlanPowerSave, (bool) PSP_SYSTEMPARAM_WLAN_POWERSAVE_OFF, true, true),
 	ReportedConfigSetting("EncryptSave", &g_Config.bEncryptSave, true, true, true),
 	ConfigSetting("SavedataUpgradeVersion", &g_Config.bSavedataUpgrade, true, true, false),
+	ConfigSetting("MemStickSize", &g_Config.iMemStickSizeGB, 16, true, false),
 
 	ConfigSetting(false),
 };
diff --git a/Core/Config.h b/Core/Config.h
index f34d87c6f3..c73c48faae 100644
--- a/Core/Config.h
+++ b/Core/Config.h
@@ -123,6 +123,7 @@ public:
 	std::string sRemoteISOSubdir;
 	bool bRemoteDebuggerOnStartup;
 	bool bMemStickInserted;
+	int iMemStickSizeGB;
 	bool bLoadPlugins;
 
 	int iScreenRotation;  // The rotation angle of the PPSSPP UI. Only supported on Android and possibly other mobile platforms.
diff --git a/Core/FileSystems/MetaFileSystem.cpp b/Core/FileSystems/MetaFileSystem.cpp
index 31f7bf5689..c7f3b46c1c 100644
--- a/Core/FileSystems/MetaFileSystem.cpp
+++ b/Core/FileSystems/MetaFileSystem.cpp
@@ -669,3 +669,17 @@ void MetaFileSystem::DoState(PointerWrap &p)
 	}
 }
 
+u64 MetaFileSystem::getDirSize(const std::string &dirPath) {
+	u64 result = 0;
+	auto allFiles = GetDirListing(dirPath);
+	for (auto file : allFiles) {
+		if (file.name == "." || file.name == "..")
+			continue;
+		if (file.type == FILETYPE_DIRECTORY) {
+			result += getDirSize(dirPath + file.name + "/");
+		} else {
+			result += file.size;
+		}
+	}
+	return result;
+}
diff --git a/Core/FileSystems/MetaFileSystem.h b/Core/FileSystems/MetaFileSystem.h
index 8294ba16da..5d3984349a 100644
--- a/Core/FileSystems/MetaFileSystem.h
+++ b/Core/FileSystems/MetaFileSystem.h
@@ -129,4 +129,6 @@ public:
 		std::lock_guard<std::recursive_mutex> guard(lock);
 		startingDirectory = dir;
 	}
+
+	u64 getDirSize(const std::string &dirPath);
 };
diff --git a/Core/HW/MemoryStick.cpp b/Core/HW/MemoryStick.cpp
index f0d9a38708..da0058261f 100644
--- a/Core/HW/MemoryStick.cpp
+++ b/Core/HW/MemoryStick.cpp
@@ -71,15 +71,18 @@ u64 MemoryStick_SectorSize() {
 }
 
 u64 MemoryStick_FreeSpace() {
-	u64 freeSpace = pspFileSystem.FreeSpace("ms0:/");
-
 	// Cap the memory stick size to avoid math errors when old games get sizes that were
 	// hard to imagine back then.
 	// We have a compat setting to make it even smaller for Harry Potter : Goblet of Fire, see #13266.
-	const u64 memStickSize = PSP_CoreParameter().compat.flags().ReportSmallMemstick ? smallMemstickSize : normalMemstickSize;
-	if (freeSpace < memStickSize)
-		return freeSpace;
-	return memStickSize;
+	const u64 memStickSize = PSP_CoreParameter().compat.flags().ReportSmallMemstick ? smallMemstickSize : (u64)g_Config.iMemStickSizeGB * 1024 * 1024 * 1024;
+	u64 usedSpace = pspFileSystem.getDirSize("ms0:/PSP/SAVEDATA/");// Assume the memory stick is only used to store savedata.
+	u64 freeSpace;
+	if (usedSpace >= memStickSize)
+		freeSpace = 0;
+	else
+		freeSpace = memStickSize - usedSpace;
+
+	return freeSpace;
 }
 
 void MemoryStick_SetFatState(MemStickFatState state) {
diff --git a/UI/GameSettingsScreen.cpp b/UI/GameSettingsScreen.cpp
index 1ae64da3ce..49cff8f2e7 100644
--- a/UI/GameSettingsScreen.cpp
+++ b/UI/GameSettingsScreen.cpp
@@ -897,6 +897,7 @@ void GameSettingsScreen::CreateViews() {
 	rewindFreq->SetZeroLabel(sy->T("Off"));
 
 	systemSettings->Add(new CheckBox(&g_Config.bMemStickInserted, sy->T("Memory Stick inserted")));
+	PopupSliderChoice *memStickSize = systemSettings->Add(new PopupSliderChoice(&g_Config.iMemStickSizeGB, 1, 128, sy->T("Change Memory Stick Size", "Change Memory Stick Size(GB)"), screenManager(), "GB"));
 
 	systemSettings->Add(new ItemHeader(sy->T("General")));