diff --git a/include/span.h b/include/span.h
index 8151737..72d55d6 100644
--- a/include/span.h
+++ b/include/span.h
@@ -1669,7 +1669,7 @@ constexpr auto as_span(span<byte, Dimensions...> s) noexcept -> span<
              ByteSpan::bounds_type::static_size % static_cast<std::size_t>(sizeof(U)) == 0),
         "Target type must be a trivial type and its size must match the byte array size");
 
-    Expects((s.bytes() % sizeof(U)) == 0);
+    Expects((s.size_bytes() % sizeof(U)) == 0);
     return {reinterpret_cast<U*>(s.data()),
             s.size_bytes() / narrow_cast<std::ptrdiff_t>(sizeof(U))};
 }