diff --git a/include/spdlog/details/pattern_formatter.h b/include/spdlog/details/pattern_formatter.h
index 9de1a6cc..672cae25 100644
--- a/include/spdlog/details/pattern_formatter.h
+++ b/include/spdlog/details/pattern_formatter.h
@@ -98,8 +98,8 @@ private:
     const padding_info &padinfo_;
     fmt::memory_buffer &dest_;
     size_t total_pad_;
-    string_view_t spaces_ = "                                                                "
-                            "                                                                ";
+    string_view_t spaces_ {"                                                                "
+                           "                                                                ", 128};
 };
 
 class flag_formatter