diff --git a/Source/Core/VideoCommon/Src/RenderBase.cpp b/Source/Core/VideoCommon/Src/RenderBase.cpp
index 2fd7a9ecdf..1237af7c55 100644
--- a/Source/Core/VideoCommon/Src/RenderBase.cpp
+++ b/Source/Core/VideoCommon/Src/RenderBase.cpp
@@ -262,13 +262,13 @@ void Renderer::CalculateXYScale(const TargetRectangle& dst_rect)
 		if (g_ActiveConfig.b3DVision)
 		{
 			// This works, yet the version in the else doesn't. No idea why.
-			xScale = (float)s_backbuffer_width / (float)s_XFB_width;
-			yScale = (float)s_backbuffer_height / (float)s_XFB_height;
+			xScale = (float)(s_backbuffer_width-1) / (float)(s_XFB_width-1);
+			yScale = (float)(s_backbuffer_height-1) / (float)(s_XFB_height-1);
 		}
 		else
 		{
-			xScale = (float)(dst_rect.right - dst_rect.left) / (float)s_XFB_width;
-			yScale = (float)(dst_rect.bottom - dst_rect.top) / (float)s_XFB_height;
+			xScale = (float)(dst_rect.right - dst_rect.left - 1) / (float)(s_XFB_width-1);
+			yScale = (float)(dst_rect.bottom - dst_rect.top - 1) / (float)(s_XFB_height-1);
 		}
 	}
 }
diff --git a/Source/Core/VideoCommon/Src/RenderBase.h b/Source/Core/VideoCommon/Src/RenderBase.h
index 0e8111cafb..9d22073e20 100644
--- a/Source/Core/VideoCommon/Src/RenderBase.h
+++ b/Source/Core/VideoCommon/Src/RenderBase.h
@@ -90,12 +90,12 @@ public:
 	virtual TargetRectangle ConvertEFBRectangle(const EFBRectangle& rc) = 0;
 
 	// Use this to upscale native EFB coordinates to IDEAL internal resolution
-	static int EFBToScaledX(int x) { return x * GetTargetWidth() / EFB_WIDTH; }
-	static int EFBToScaledY(int y) { return y * GetTargetHeight() / EFB_HEIGHT; }
+	static int EFBToScaledX(int x) { return x * (GetTargetWidth()-1) / (EFB_WIDTH-1); }
+	static int EFBToScaledY(int y) { return y * (GetTargetHeight()-1) / (EFB_HEIGHT-1); }
 
 	// Floating point versions of the above - only use them if really necessary
-	static float EFBToScaledXf(float x) { return x * (float)GetTargetWidth() / (float)EFB_WIDTH; }
-	static float EFBToScaledYf(float y) { return y * (float)GetTargetHeight() / (float)EFB_HEIGHT; }
+	static float EFBToScaledXf(float x) { return x * (float)(GetTargetWidth()-1) / (float)(EFB_WIDTH-1); }
+	static float EFBToScaledYf(float y) { return y * (float)(GetTargetHeight()-1) / (float)(EFB_HEIGHT-1); }
 
 	// Returns the offset at which the EFB will be drawn onto the backbuffer
 	// NOTE: Never calculate this manually (e.g. to "increase accuracy"), since you might end up getting off-by-one errors.