diff --git a/Source/Glide64/Main.cpp b/Source/Glide64/Main.cpp
index d4429ce9b..3d972ddd2 100644
--- a/Source/Glide64/Main.cpp
+++ b/Source/Glide64/Main.cpp
@@ -202,32 +202,7 @@ void _ChangeSize()
 
 void ChangeSize()
 {
-    switch (g_settings->aspectmode)
-    {
-    case 0: //4:3
-        if (g_settings->scr_res_x >= g_settings->scr_res_y * 4.0f / 3.0f) {
-            g_settings->res_y = g_settings->scr_res_y;
-            g_settings->res_x = (uint32_t)(g_settings->res_y * 4.0f / 3.0f);
-        }
-        else {
-            g_settings->res_x = g_settings->scr_res_x;
-            g_settings->res_y = (uint32_t)(g_settings->res_x / 4.0f * 3.0f);
-        }
-        break;
-    case 1: //16:9
-        if (g_settings->scr_res_x >= g_settings->scr_res_y * 16.0f / 9.0f) {
-            g_settings->res_y = g_settings->scr_res_y;
-            g_settings->res_x = (uint32_t)(g_settings->res_y * 16.0f / 9.0f);
-        }
-        else {
-            g_settings->res_x = g_settings->scr_res_x;
-            g_settings->res_y = (uint32_t)(g_settings->res_x / 16.0f * 9.0f);
-        }
-        break;
-    default: //stretch or original
-        g_settings->res_x = g_settings->scr_res_x;
-        g_settings->res_y = g_settings->scr_res_y;
-    }
+    g_settings->UpdateAspectRatio();
     _ChangeSize();
     rdp.offset_x = (g_settings->scr_res_x - g_settings->res_x) / 2.0f;
     float offset_y = (g_settings->scr_res_y - g_settings->res_y) / 2.0f;
diff --git a/Source/Glide64/Settings.cpp b/Source/Glide64/Settings.cpp
index 1c3e1f9b4..cd0592ea0 100644
--- a/Source/Glide64/Settings.cpp
+++ b/Source/Glide64/Settings.cpp
@@ -237,6 +237,39 @@ void CSettings::UpdateFrameBufferBits(uint32_t BitsToAdd, uint32_t BitsToRemove)
     }
 }
 
+void CSettings::UpdateAspectRatio(void)
+{
+    switch (aspectmode)
+    {
+    case 0: //4:3
+        if (scr_res_x >= scr_res_y * 4.0f / 3.0f) {
+            res_y = scr_res_y;
+            res_x = (uint32_t)(res_y * 4.0f / 3.0f);
+        }
+        else
+        {
+            res_x = scr_res_x;
+            res_y = (uint32_t)(res_x / 4.0f * 3.0f);
+        }
+        break;
+    case 1: //16:9
+        if (scr_res_x >= scr_res_y * 16.0f / 9.0f)
+        {
+            res_y = scr_res_y;
+            res_x = (uint32_t)(res_y * 16.0f / 9.0f);
+        }
+        else
+        {
+            res_x = scr_res_x;
+            res_y = (uint32_t)(res_x / 16.0f * 9.0f);
+        }
+        break;
+    default: //stretch or original
+        res_x = scr_res_x;
+        res_y = scr_res_y;
+    }
+}
+
 void CSettings::ReadSettings()
 {
 #ifdef ANDROID
diff --git a/Source/Glide64/Settings.h b/Source/Glide64/Settings.h
index 344f62d5d..045bcf329 100644
--- a/Source/Glide64/Settings.h
+++ b/Source/Glide64/Settings.h
@@ -179,6 +179,7 @@ public:
 
     void ReadGameSettings(const char * name);
     void WriteSettings(void);
+    void UpdateAspectRatio(void);
 
 private:
     void ReadSettings();