diff --git a/include/boost/charconv/detail/fast_float/float_common.hpp b/include/boost/charconv/detail/fast_float/float_common.hpp
index 0b9d3aee..627f97f7 100644
--- a/include/boost/charconv/detail/fast_float/float_common.hpp
+++ b/include/boost/charconv/detail/fast_float/float_common.hpp
@@ -315,7 +315,7 @@ struct binary_format_lookup_tables<double, U> {
 
   // Largest integer value v so that (5**index * v) <= 1<<53.
   // 0x10000000000000 == 1 << 53
-  static constexpr std::uint64_t max_mantissa[] = {
+  static constexpr uint64_t max_mantissa[] = {
     UINT64_C(0x10000000000000),
     UINT64_C(0x10000000000000) / UINT64_C(5),
     UINT64_C(0x10000000000000) / (UINT64_C(5) * UINT64_C(5)),