diff --git a/include/fast_float/constexpr_feature_detect.h b/include/fast_float/constexpr_feature_detect.h
index 20a998e..a26355f 100644
--- a/include/fast_float/constexpr_feature_detect.h
+++ b/include/fast_float/constexpr_feature_detect.h
@@ -79,7 +79,7 @@
 #define FASTFLOAT_IS_CONSTEXPR 1
 #define FASTFLOAT_HAS_IS_CONSTANT_EVALUATED 1
 #else
-#define FASTFLOAT_CONSTEVAL FASTFLOAT_CONSTEXPR14
+#define FASTFLOAT_CONSTEVAL constexpr
 #define FASTFLOAT_CONSTEXPR20
 #define FASTFLOAT_IS_CONSTEXPR 0
 #define FASTFLOAT_HAS_IS_CONSTANT_EVALUATED 0