diff --git a/microscript/ILibDuktape_Polyfills.c b/microscript/ILibDuktape_Polyfills.c
index 4b54a3f..0a63459 100644
--- a/microscript/ILibDuktape_Polyfills.c
+++ b/microscript/ILibDuktape_Polyfills.c
@@ -160,10 +160,10 @@ duk_ret_t ILibDuktape_Polyfills_Buffer_toString(duk_context *ctx)
 #ifdef WIN32
 		else if (strcmp(cType, "utf16") == 0)
 		{
-			int sz = (MultiByteToWideChar(CP_UTF8, 0, buffer, bufferLen, NULL, 0) * 2);
+			int sz = (MultiByteToWideChar(CP_UTF8, 0, buffer, (int)bufferLen, NULL, 0) * 2);
 			WCHAR* b = duk_push_fixed_buffer(ctx, sz);
 			duk_push_buffer_object(ctx, -1, 0, sz, DUK_BUFOBJ_NODEJS_BUFFER);
-			MultiByteToWideChar(CP_UTF8, 0, buffer, bufferLen, b, sz / 2);
+			MultiByteToWideChar(CP_UTF8, 0, buffer, (int)bufferLen, b, sz / 2);
 		}
 #endif
 		else