diff --git a/include/fmt/chrono.h b/include/fmt/chrono.h
index 177e79b6b1be..03fac9a76498 100644
--- a/include/fmt/chrono.h
+++ b/include/fmt/chrono.h
@@ -1091,7 +1091,7 @@ void write_floating_seconds(memory_buffer& buf, Duration duration,
       num_fractional_digits = 6;
   }
 
-  format_to(std::back_inserter(buf), runtime("{:.{}f}"),
+  format_to(std::back_inserter(buf), FMT_STRING("{:.{}f}"),
             std::fmod(val * static_cast<rep>(Duration::period::num) /
                           static_cast<rep>(Duration::period::den),
                       static_cast<rep>(60)),