diff --git a/Core/Core.cpp b/Core/Core.cpp
index 93c6eaf8d850..8d8ca89cd9e4 100644
--- a/Core/Core.cpp
+++ b/Core/Core.cpp
@@ -150,7 +150,12 @@ static bool IsWindowSmall(int pixelWidth, int pixelHeight) {
 // TODO: Feels like this belongs elsewhere.
 bool UpdateScreenScale(int width, int height) {
 	bool smallWindow;
-#if PPSSPP_PLATFORM(WINDOWS) && !PPSSPP_PLATFORM(UWP)
+#if defined(USING_QT_UI)
+	g_dpi = System_GetPropertyFloat(SYSPROP_DISPLAY_DPI);
+	float g_logical_dpi = System_GetPropertyFloat(SYSPROP_DISPLAY_LOGICAL_DPI);
+	g_dpi_scale_x = g_logical_dpi / g_dpi;
+	g_dpi_scale_y = g_logical_dpi / g_dpi;
+#elif PPSSPP_PLATFORM(WINDOWS) && !PPSSPP_PLATFORM(UWP)
 	g_dpi = (float)System_GetPropertyInt(SYSPROP_DISPLAY_DPI);
 	g_dpi_scale_x = 96.0f / g_dpi;
 	g_dpi_scale_y = 96.0f / g_dpi;
diff --git a/Qt/QtMain.cpp b/Qt/QtMain.cpp
index 3c9641c1bd3f..83043c150e51 100644
--- a/Qt/QtMain.cpp
+++ b/Qt/QtMain.cpp
@@ -159,11 +159,24 @@ int System_GetPropertyInt(SystemProperty prop) {
 #else
 		return DEVICE_TYPE_DESKTOP;
 #endif
+	case SYSPROP_DISPLAY_COUNT:
+		return QApplication::screens().size();
 	default:
 		return -1;
 	}
 }
 
+int System_GetPropertyFloat(SystemProperty prop) {
+	switch (prop) {
+	case SYSPROP_DISPLAY_LOGICAL_DPI:
+		return QApplication::primaryScreen()->logicalDotsPerInch();
+	case SYSPROP_DISPLAY_DPI:
+		return QApplication::primaryScreen()->physicalDotsPerInch();
+	default:
+		return System_GetPropertyInt(prop);
+	}
+}
+
 bool System_GetPropertyBool(SystemProperty prop) {
 	switch (prop) {
 	case SYSPROP_HAS_BACK_BUTTON:
@@ -229,16 +242,6 @@ void LaunchBrowser(const char *url)
 	QDesktopServices::openUrl(QUrl(url));
 }
 
-float CalculateDPIScale()
-{
-	// Sane default rather than check DPI
-#if defined(USING_GLES2)
-	return 1.2f;
-#else
-	return 1.0f;
-#endif
-}
-
 static int mainInternal(QApplication &a) {
 #ifdef MOBILE_DEVICE
 	emugl = new MainUI();
@@ -628,19 +631,21 @@ int main(int argc, char *argv[])
 	QGLFormat::setDefaultFormat(format);
 
 	QApplication a(argc, argv);
-	QSize res = QApplication::desktop()->screenGeometry().size();
+	QScreen* screen = a.primaryScreen();
+	QSizeF res = screen->physicalSize();
 	if (res.width() < res.height())
 		res.transpose();
 	pixel_xres = res.width();
 	pixel_yres = res.height();
-	g_dpi_scale_x = CalculateDPIScale();
-	g_dpi_scale_y = CalculateDPIScale();
+
+	g_dpi_scale_x = screen->logicalDotsPerInchX() / screen->physicalDotsPerInchX();
+	g_dpi_scale_y = screen->logicalDotsPerInchY() / screen->physicalDotsPerInchY();
 	g_dpi_scale_real_x = g_dpi_scale_x;
 	g_dpi_scale_real_y = g_dpi_scale_y;
 	dp_xres = (int)(pixel_xres * g_dpi_scale_x);
 	dp_yres = (int)(pixel_yres * g_dpi_scale_y);
 
-	refreshRate = (int)(a.primaryScreen()->refreshRate() * 1000);
+	refreshRate = (int)(screen->refreshRate() * 1000);
 
 	std::string savegame_dir = ".";
 	std::string external_dir = ".";
@@ -669,4 +674,3 @@ int main(int argc, char *argv[])
 	glslang::FinalizeProcess();
 	return ret;
 }
-
diff --git a/Qt/mainwindow.cpp b/Qt/mainwindow.cpp
index 4b4a6aaaf7c4..8b59c683eada 100644
--- a/Qt/mainwindow.cpp
+++ b/Qt/mainwindow.cpp
@@ -24,7 +24,7 @@ MainWindow::MainWindow(QWidget *parent, bool fullscreen) :
 {
 	QDesktopWidget *desktop = QApplication::desktop();
 	int screenNum = QProcessEnvironment::systemEnvironment().value("SDL_VIDEO_FULLSCREEN_HEAD", "0").toInt();
-	
+
 	// Move window to the center of selected screen
 	QRect rect = desktop->screenGeometry(screenNum);
 	move((rect.width()-frameGeometry().width()) / 4, (rect.height()-frameGeometry().height()) / 4);
@@ -295,19 +295,22 @@ void MainWindow::consoleAct()
 void MainWindow::raiseTopMost()
 {
 	setWindowState( (windowState() & ~Qt::WindowMinimized) | Qt::WindowActive);
-	raise();  
+	raise();
 	activateWindow();
 }
 
 void MainWindow::SetFullScreen(bool fullscreen) {
 	if (fullscreen) {
+#if !PPSSPP_PLATFORM(MAC)
 		menuBar()->hide();
-		
+
 		emugl->setFixedSize(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX);
+		// TODO: Shouldn't this be physicalSize()?
 		emugl->resizeGL(emugl->size().width(), emugl->size().height());
 		// TODO: Won't showFullScreen do this for us?
 		setMaximumSize(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX);
 		setFixedSize(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX);
+#endif
 
 		showFullScreen();
 		InitPadLayout(dp_xres, dp_yres);
@@ -315,8 +318,10 @@ void MainWindow::SetFullScreen(bool fullscreen) {
 		if (GetUIState() == UISTATE_INGAME && !g_Config.bShowTouchControls)
 			QApplication::setOverrideCursor(QCursor(Qt::BlankCursor));
 	} else {
+#if !PPSSPP_PLATFORM(MAC)
 		menuBar()->show();
 		updateMenus();
+#endif
 
 		showNormal();
 		SetWindowScale(-1);
@@ -346,7 +351,7 @@ void MainWindow::forumAct()
 	QDesktopServices::openUrl(QUrl("https://forums.ppsspp.org/"));
 }
 
-void MainWindow::gitAct() 
+void MainWindow::gitAct()
 {
 	QDesktopServices::openUrl(QUrl("https://github.com/hrydgard/ppsspp/"));
 }
@@ -394,9 +399,14 @@ void MainWindow::SetWindowScale(int zoom) {
 	g_Config.iWindowWidth = width;
 	g_Config.iWindowHeight = height;
 
+#if !PPSSPP_PLATFORM(MAC)
 	emugl->setFixedSize(g_Config.iWindowWidth, g_Config.iWindowHeight);
+	// TODO: Shouldn't this be scaled size?
 	emugl->resizeGL(g_Config.iWindowWidth, g_Config.iWindowHeight);
 	setFixedSize(sizeHint());
+#else
+	resize(g_Config.iWindowWidth, g_Config.iWindowHeight);
+#endif
 }
 
 void MainWindow::SetGameTitle(QString text)
@@ -585,7 +595,7 @@ void MainWindow::createMenus()
 		}
 	}
 	langMenu->addActions(langGroup->actions());
-	
+
 	// Help
 	MenuTree* helpMenu = new MenuTree(this, menuBar(),    QT_TR_NOOP("&Help"));
 	helpMenu->add(new MenuAction(this, SLOT(websiteAct()),    QT_TR_NOOP("Official &website"), QKeySequence::HelpContents));
diff --git a/ext/native/base/NativeApp.h b/ext/native/base/NativeApp.h
index da2fba06bac5..188bcbaa52be 100644
--- a/ext/native/base/NativeApp.h
+++ b/ext/native/base/NativeApp.h
@@ -149,6 +149,7 @@ enum SystemProperty {
 	SYSPROP_DISPLAY_XRES,
 	SYSPROP_DISPLAY_YRES,
 	SYSPROP_DISPLAY_REFRESH_RATE,  // returns 1000*the refresh rate in Hz as it can be non-integer
+	SYSPROP_DISPLAY_LOGICAL_DPI,
 	SYSPROP_DISPLAY_DPI,
 	SYSPROP_DISPLAY_COUNT,
 	SYSPROP_MOGA_VERSION,
@@ -173,6 +174,7 @@ enum SystemProperty {
 
 std::string System_GetProperty(SystemProperty prop);
 int System_GetPropertyInt(SystemProperty prop);
+int System_GetPropertyFloat(SystemProperty prop);
 bool System_GetPropertyBool(SystemProperty prop);
 
 std::vector<std::string> __cameraGetDeviceList();