diff --git a/include/wx/unichar.h b/include/wx/unichar.h
index bbd75466bf..5d731754b1 100644
--- a/include/wx/unichar.h
+++ b/include/wx/unichar.h
@@ -93,14 +93,14 @@ public:
     static wxUint16 HighSurrogate(wxUint32 value)
     {
         wxASSERT_MSG(IsSupplementary(value), "wxUniChar::HighSurrogate() must be called on a supplementary character");
-        return 0xD800 | ((value - 0x10000) >> 10);
+        return static_cast<wxUint16>(0xD800 | ((value - 0x10000) >> 10));
     }
 
     // Returns the low surrogate code unit for the supplementary character
     static wxUint16 LowSurrogate(wxUint32 value)
     {
         wxASSERT_MSG(IsSupplementary(value), "wxUniChar::LowSurrogate() must be called on a supplementary character");
-        return 0xDC00 | ((value - 0x10000) & 0x03FF);
+        return static_cast<wxUint16>(0xDC00 | ((value - 0x10000) & 0x03FF));
     }
 
     // Returns true if the character is a BMP character: