diff --git a/src/dd.c b/src/dd.c
index ab5fc5b..81d4109 100644
--- a/src/dd.c
+++ b/src/dd.c
@@ -802,12 +802,12 @@ HRESULT dd_SetDisplayMode(DWORD dwWidth, DWORD dwHeight, DWORD dwBPP, DWORD dwFl
     {
         g_ddraw->render.viewport.width = g_ddraw->render.width;
         g_ddraw->render.viewport.height =
-            (int)(((float)g_ddraw->height / g_ddraw->width) * g_ddraw->render.viewport.width);
+            (int)(((double)g_ddraw->height / g_ddraw->width) * g_ddraw->render.viewport.width);
 
         if (g_ddraw->render.viewport.height > g_ddraw->render.height)
         {
             g_ddraw->render.viewport.width =
-                (int)(((float)g_ddraw->render.viewport.width / g_ddraw->render.viewport.height) * g_ddraw->render.height);
+                (int)(((double)g_ddraw->render.viewport.width / g_ddraw->render.viewport.height) * g_ddraw->render.height);
 
             g_ddraw->render.viewport.height = g_ddraw->render.height;
         }
diff --git a/src/utils.c b/src/utils.c
index 41a4c08..986d123 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -381,11 +381,11 @@ void util_toggle_maximize()
             dst_rc.top = 0;
             dst_rc.left = 0;
             dst_rc.right = w;
-            dst_rc.bottom = (LONG)(((float)g_ddraw->height / g_ddraw->width) * w);
+            dst_rc.bottom = (LONG)(((double)g_ddraw->height / g_ddraw->width) * w);
 
             if (dst_rc.bottom > h)
             {
-                dst_rc.right = (LONG)(((float)dst_rc.right / dst_rc.bottom) * h);
+                dst_rc.right = (LONG)(((double)dst_rc.right / dst_rc.bottom) * h);
                 dst_rc.bottom = h;
             }
 
diff --git a/src/wndproc.c b/src/wndproc.c
index db1c00a..aaa85a3 100644
--- a/src/wndproc.c
+++ b/src/wndproc.c
@@ -314,8 +314,8 @@ LRESULT CALLBACK fake_WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam
                         real_GetWindowLongA(hWnd, GWL_EXSTYLE)) &&
                     SetRect(&clientrc, 0, 0, clientrc.right - clientrc.left, clientrc.bottom - clientrc.top))
                 {
-                    float scaleH = (float)g_ddraw->height / g_ddraw->width;
-                    float scaleW = (float)g_ddraw->width / g_ddraw->height;
+                    double scaleH = (double)g_ddraw->height / g_ddraw->width;
+                    double scaleW = (double)g_ddraw->width / g_ddraw->height;
 
                     switch (wParam)
                     {