diff --git a/include/wx/private/webrequest.h b/include/wx/private/webrequest.h
index 3f3bca6158..4a515daa02 100644
--- a/include/wx/private/webrequest.h
+++ b/include/wx/private/webrequest.h
@@ -18,6 +18,9 @@
 
 WX_DECLARE_STRING_HASH_MAP(wxString, wxWebRequestHeaderMap);
 
+// Default buffer size when a fixed-size buffer must be used.
+const int wxWEBREQUEST_BUFFER_SIZE = 64 * 1024;
+
 // ----------------------------------------------------------------------------
 // wxWebAuthChallengeImpl
 // ----------------------------------------------------------------------------
diff --git a/src/common/webrequest.cpp b/src/common/webrequest.cpp
index 5de8f13949..7193786731 100644
--- a/src/common/webrequest.cpp
+++ b/src/common/webrequest.cpp
@@ -509,7 +509,7 @@ wxWebAuthChallenge::SetCredentials(const wxWebCredentials& cred)
 
 wxWebResponseImpl::wxWebResponseImpl(wxWebRequestImpl& request) :
     m_request(request),
-    m_readSize(8 * 1024)
+    m_readSize(wxWEBREQUEST_BUFFER_SIZE)
 {
 }
 
diff --git a/src/msw/webrequest_winhttp.cpp b/src/msw/webrequest_winhttp.cpp
index a097f5d144..75ec43edb2 100644
--- a/src/msw/webrequest_winhttp.cpp
+++ b/src/msw/webrequest_winhttp.cpp
@@ -194,7 +194,7 @@ wxWebRequestWinHTTP::HandleCallback(DWORD dwInternetStatus,
 
 void wxWebRequestWinHTTP::WriteData()
 {
-    int dataWriteSize = 8 * 1024;
+    int dataWriteSize = wxWEBREQUEST_BUFFER_SIZE;
     if ( m_dataWritten + dataWriteSize > m_dataSize )
         dataWriteSize = m_dataSize - m_dataWritten;
     if ( !dataWriteSize )