diff --git a/src/WebResponses.cpp b/src/WebResponses.cpp
index a22e991aa..b252de112 100644
--- a/src/WebResponses.cpp
+++ b/src/WebResponses.cpp
@@ -130,6 +130,7 @@ String AsyncWebServerResponse::_assembleHead(uint8_t version){
       addHeader("Transfer-Encoding","chunked");
   }
   String out = String();
+  out.reserve(95 * _headers.length()); 
   int bufSize = 300;
   char buf[bufSize];