diff --git a/algo/search.hpp b/algo/search.hpp
index 1cc4ba8e..c66649ee 100644
--- a/algo/search.hpp
+++ b/algo/search.hpp
@@ -76,7 +76,7 @@ namespace cruft::search {
     /// in the first instance (otherwise the algorithm will return `begin`
     /// immediately. But it is not an error to do so.
     template <typename IteratorT>
-    IteratorT
+    constexpr IteratorT
     balanced (
         IteratorT begin,
         IteratorT const end,