diff --git a/common/string_utils.cpp b/common/string_utils.cpp
index a60232e492..27593d4d4c 100644
--- a/common/string_utils.cpp
+++ b/common/string_utils.cpp
@@ -50,6 +50,8 @@ wxString ConvertToNewOverbarNotation( const wxString& aOldStr )
     if( aOldStr == "~" )
         return aOldStr;
 
+    newStr.reserve( aOldStr.length() );
+
     for( wxString::const_iterator chIt = aOldStr.begin(); chIt != aOldStr.end(); ++chIt )
     {
         if( *chIt == '~' )
@@ -327,6 +329,8 @@ wxString TitleCaps( const wxString& aString )
 
     wxStringSplit( aString, words, ' ' );
 
+    result.reserve( aString.length() );
+
     for( const wxString& word : words )
     {
         if( !result.IsEmpty() )
@@ -445,6 +449,8 @@ std::string EscapedUTF8( const wxString& aString )
 
     std::string ret;
 
+    ret.reserve( utf8.length() + 2 );
+
     ret += '"';
 
     for( std::string::const_iterator it = utf8.begin();  it!=utf8.end();  ++it )
@@ -476,6 +482,8 @@ wxString EscapeHTML( const wxString& aString )
 {
     wxString converted;
 
+    converted.reserve( aString.length() );
+
     for( wxUniChar c : aString )
     {
         if( c == '\"' )