diff --git a/app/javascript/mastodon/features/compose/containers/compose_form_container.js b/app/javascript/mastodon/features/compose/containers/compose_form_container.js
--- a/app/javascript/mastodon/features/compose/containers/compose_form_container.js
+++ b/app/javascript/mastodon/features/compose/containers/compose_form_container.js
@@ -32,5 +32,5 @@
   isInReply: state.getIn(['compose', 'in_reply_to']) !== null,
   lang: state.getIn(['compose', 'language']),
-  maxChars: state.getIn(['server', 'server', 'configuration', 'statuses', 'max_characters'], 500),
+  maxChars: state.getIn(['server', 'server', 'configuration', 'statuses', 'max_characters'], 5000),
 });

diff --git a/app/validators/status_length_validator.rb b/app/validators/status_length_validator.rb
--- a/app/validators/status_length_validator.rb
+++ b/app/validators/status_length_validator.rb
@@ -2,6 +2,6 @@

 class StatusLengthValidator < ActiveModel::Validator
-  MAX_CHARS = 500
+  MAX_CHARS = 5000
   URL_PLACEHOLDER_CHARS = 23
   URL_PLACEHOLDER = 'x' * 23