diff --git a/include/beman/utf_view/to_utf_view.hpp b/include/beman/utf_view/to_utf_view.hpp
index deaad99..f13aee2 100644
--- a/include/beman/utf_view/to_utf_view.hpp
+++ b/include/beman/utf_view/to_utf_view.hpp
@@ -229,13 +229,20 @@ class to_utf_view : public std::ranges::view_interface<to_utf_view<V, E, ToType>
     return std::ranges::empty(exposition_only_base_);
   }
 
-  constexpr std::size_t size()
+  constexpr auto size()
     requires std::ranges::sized_range<V> &&
              std::same_as<char32_t, std::ranges::range_value_t<V>> &&
              std::same_as<char32_t, ToType> {
     return std::ranges::size(exposition_only_base_);
   }
 
+  constexpr auto size() const
+    requires std::ranges::sized_range<const V> &&
+             std::same_as<char32_t, std::ranges::range_value_t<const V>> &&
+             std::same_as<char32_t, ToType> {
+    return std::ranges::size(exposition_only_base_);
+  }
+
   /* !PAPER */
 #if defined(__cpp_lib_ranges_reserve_hint)
   /* PAPER:   constexpr auto reserve_hint() requires approximately_sized_range<V>; */
diff --git a/papers/P2728.md b/papers/P2728.md
index 6a0720c..a7564d5 100644
--- a/papers/P2728.md
+++ b/papers/P2728.md
@@ -709,12 +709,18 @@ public:
 
   constexpr bool empty() const { return empty(@*base_*@); }
 
-  constexpr size_t size()
+  constexpr auto size()
     requires sized_range<V> && same_as<char32_t, range_value_t<V>> && same_as<char32_t, ToType>
   {
     return size(@*base_*@);
   }
 
+  constexpr auto size() const
+    requires sized_range<const V> && same_as<char32_t, range_value_t<const V>> && same_as<char32_t, ToType>
+  {
+    return size(@*base_*@);
+  }
+
   constexpr auto reserve_hint() requires approximately_sized_range<V>;
   constexpr auto reserve_hint() const requires approximately_sized_range<const V>;
 };
diff --git a/tests/beman/utf_view/to_utf_view.test.cpp b/tests/beman/utf_view/to_utf_view.test.cpp
index 97052fb..9beaed1 100644
--- a/tests/beman/utf_view/to_utf_view.test.cpp
+++ b/tests/beman/utf_view/to_utf_view.test.cpp
@@ -84,6 +84,19 @@ static_assert(
                   test_bidi_iterator<char8_t>, test_bidi_iterator<char8_t>>,
               to_utf_view_kind::replacement, char8_t>>>);
 
+// size() is only available when a UTF-32 -> UTF-32 view is transcoding a sized range.
+static_assert(std::ranges::sized_range<
+              to_utf_view<std::u32string_view, to_utf_view_kind::replacement, char32_t>>);
+static_assert(std::ranges::sized_range<
+              const to_utf_view<std::u32string_view, to_utf_view_kind::replacement, char32_t>>);
+static_assert(!std::ranges::sized_range<
+              to_utf_view<std::u8string_view, to_utf_view_kind::replacement, char32_t>>);
+static_assert(!std::ranges::sized_range<
+              to_utf_view<std::u32string_view, to_utf_view_kind::replacement, char8_t>>);
+static_assert(!std::ranges::sized_range<
+              to_utf_view<std::ranges::subrange<test_forward_iterator<char32_t>, std::default_sentinel_t>,
+                          to_utf_view_kind::replacement, char32_t>>);
+
 template <exposition_only_code_unit CharT>
 using test_case_code_unit_result = std::expected<CharT, utf_transcoding_error>;