diff --git a/f_to_string.hpp b/f_to_string.hpp
index 204a5f2..df4d7be 100644
--- a/f_to_string.hpp
+++ b/f_to_string.hpp
@@ -68,7 +68,7 @@ class f_to_string_t {
     constexpr auto size() const noexcept { return sizeof(buf) / sizeof(buf[0]); }
     // Element access
     constexpr auto data() noexcept { return buf; }
-    constexpr const auto data() const noexcept { return buf; }
+    constexpr auto data() const noexcept { return buf; }
     constexpr auto& operator[](unsigned int i) noexcept { return buf[i]; }
     constexpr const auto& operator[](unsigned int i) const noexcept { return buf[i]; }
     constexpr auto& front() noexcept { return buf[0]; }
@@ -77,9 +77,9 @@ class f_to_string_t {
     constexpr const auto& back() const noexcept { return buf[size() - 1]; }
     // Iterators
     constexpr auto begin() noexcept { return buf; }
-    constexpr const auto begin() const noexcept { return buf; }
+    constexpr auto begin() const noexcept { return buf; }
     constexpr auto end() noexcept { return buf + size(); }
-    constexpr const auto end() const noexcept { return buf + size(); }
+    constexpr auto end() const noexcept { return buf + size(); }
 };
 
 } // namespace constexpr_to_string
diff --git a/to_string.hpp b/to_string.hpp
index d0a4dbe..257718c 100644
--- a/to_string.hpp
+++ b/to_string.hpp
@@ -58,7 +58,7 @@ class to_string_t {
 
     // Element access
     constexpr auto data() noexcept { return buf; }
-    constexpr const auto data() const noexcept { return buf; }
+    constexpr auto data() const noexcept { return buf; }
     constexpr auto& operator[](unsigned int i) noexcept { return buf[i]; }
     constexpr const auto& operator[](unsigned int i) const noexcept { return buf[i]; }
     constexpr auto& front() noexcept { return buf[0]; }
@@ -68,9 +68,9 @@ class to_string_t {
 
     // Iterators
     constexpr auto begin() noexcept { return buf; }
-    constexpr const auto begin() const noexcept { return buf; }
+    constexpr auto begin() const noexcept { return buf; }
     constexpr auto end() noexcept { return buf + size(); }
-    constexpr const auto end() const noexcept { return buf + size(); }
+    constexpr auto end() const noexcept { return buf + size(); }
 };
 
 } // namespace constexpr_to_string