diff --git a/org/qmckl_mo.org b/org/qmckl_mo.org
index a9a2047..eb37368 100644
--- a/org/qmckl_mo.org
+++ b/org/qmckl_mo.org
@@ -425,7 +425,7 @@ qmckl_get_mo_basis_mo_vgl(qmckl_context context,
   qmckl_context_struct* const ctx = (qmckl_context_struct* const) context;
   assert (ctx != NULL);
 
-  size_t sze = ctx->point.num * 5 * ctx->mo_basis.mo_num;
+  const int64_t sze = ctx->point.num * 5 * ctx->mo_basis.mo_num;
   if (size_max < sze) {
     return qmckl_failwith( context,
                            QMCKL_INVALID_ARG_3,
@@ -481,7 +481,7 @@ qmckl_get_mo_basis_mo_vgl_inplace (qmckl_context context,
   qmckl_context_struct* const ctx = (qmckl_context_struct* const) context;
   assert (ctx != NULL);
 
-  int64_t sze = ctx->mo_basis.mo_num * 5 * ctx->point.num;
+  const int64_t sze = ctx->mo_basis.mo_num * 5 * ctx->point.num;
   if (size_max < sze) {
     return qmckl_failwith( context,
                            QMCKL_INVALID_ARG_3,