diff --git a/app/assets/javascripts/discourse/models/composer.js b/app/assets/javascripts/discourse/models/composer.js
index a9dda18c5ac..8f6d2d3ca5d 100644
--- a/app/assets/javascripts/discourse/models/composer.js
+++ b/app/assets/javascripts/discourse/models/composer.js
@@ -179,12 +179,12 @@ Discourse.Composer = Discourse.Model.extend({
     }
 
     // reply is always required
-    if (this.get('replyLength') < Discourse.SiteSettings.min_post_length) return true;
+    if (this.get('missingReplyCharacters') > 0) return true;
 
     if (this.get('canCategorize') && !Discourse.SiteSettings.allow_uncategorized_topics && !this.get('categoryName')) return true;
 
     return false;
-  }.property('loading', 'editTitle', 'titleLength', 'targetUsernames', 'replyLength', 'categoryName'),
+  }.property('loading', 'editTitle', 'titleLength', 'targetUsernames', 'replyLength', 'categoryName', 'missingReplyCharacters'),
 
   titleLengthValid: function() {
     if (this.get('creatingPrivateMessage')) {
@@ -193,7 +193,7 @@ Discourse.Composer = Discourse.Model.extend({
       if (this.get('titleLength') < Discourse.SiteSettings.min_topic_title_length) return false;
     }
     return (this.get('titleLength') <= Discourse.SiteSettings.max_topic_title_length);
-  }.property('titleLength'),
+  }.property('creatingPrivateMessage', 'titleLength'),
 
   // The text for the save button
   saveText: function() {
@@ -531,12 +531,21 @@ Discourse.Composer = Discourse.Model.extend({
     @property missingTitleCharacters
   **/
   missingTitleCharacters: function() {
+    return this.get('minimumTitleLength') - this.get('titleLength');
+  }.property('minimumTitleLength', 'titleLength'),
+
+  /**
+    Minimum number of characters for a title to be valid.
+
+    @property minimumTitleLength
+  **/
+  minimumTitleLength: function() {
     if (this.get('creatingPrivateMessage')) {
-      return Discourse.SiteSettings.min_private_message_title_length - this.get('titleLength');
+      return Discourse.SiteSettings.min_private_message_title_length;
     } else {
-      return Discourse.SiteSettings.min_topic_title_length - this.get('titleLength');
+      return Discourse.SiteSettings.min_topic_title_length;
     }
-  }.property('titleLength'),
+  }.property('creatingPrivateMessage'),
 
 
   /**
@@ -545,8 +554,21 @@ Discourse.Composer = Discourse.Model.extend({
     @property missingReplyCharacters
   **/
   missingReplyCharacters: function() {
-    return Discourse.SiteSettings.min_post_length - this.get('replyLength');
-  }.property('replyLength'),
+    return this.get('minimumPostLength') - this.get('replyLength');
+  }.property('minimumPostLength', 'replyLength'),
+
+  /**
+    Minimum number of characters for a post body to be valid.
+
+    @property minimumPostLength
+  **/
+  minimumPostLength: function() {
+    if( this.get('creatingPrivateMessage') ) {
+      return Discourse.SiteSettings.min_private_message_post_length;
+    } else {
+      return Discourse.SiteSettings.min_post_length;
+    }
+  }.property('creatingPrivateMessage'),
 
   /**
     Computes the length of the title minus non-significant whitespaces
diff --git a/app/assets/javascripts/discourse/views/composer_view.js b/app/assets/javascripts/discourse/views/composer_view.js
index 009d3c18e43..c531dfa8591 100644
--- a/app/assets/javascripts/discourse/views/composer_view.js
+++ b/app/assets/javascripts/discourse/views/composer_view.js
@@ -368,20 +368,21 @@ Discourse.ComposerView = Discourse.View.extend({
   },
 
   titleValidation: function() {
-    var title = this.get('content.title'), reason;
-    var minLength = (this.get('content.creatingPrivateMessage') ? Discourse.SiteSettings.min_private_message_title_length : Discourse.SiteSettings.min_topic_title_length);
-    if( !title || title.length < 1 ){
+    var titleLength = this.get('content.titleLength'),
+        missingChars = this.get('content.missingTitleCharacters'),
+        reason;
+    if( titleLength < 1 ){
       reason = Em.String.i18n('composer.error.title_missing');
-    } else if( title.length < minLength ) {
-      reason = Em.String.i18n('composer.error.title_too_short', {min: minLength})
-    } else if( title.length > Discourse.SiteSettings.max_topic_title_length ) {
-      reason = Em.String.i18n('composer.error.title_too_long', {max: Discourse.SiteSettings.max_topic_title_length})
+    } else if( missingChars > 0 ) {
+      reason = Em.String.i18n('composer.error.title_too_short', {min: this.get('content.minimumTitleLength')});
+    } else if( titleLength > Discourse.SiteSettings.max_topic_title_length ) {
+      reason = Em.String.i18n('composer.error.title_too_long', {max: Discourse.SiteSettings.max_topic_title_length});
     }
 
     if( reason ) {
       return Discourse.InputValidation.create({ failed: true, reason: reason });
     }
-  }.property('content.title'),
+  }.property('content.titleLength', 'content.missingTitleCharacters', 'content.minimumTitleLength'),
 
   categoryValidation: function() {
     if( !Discourse.SiteSettings.allow_uncategorized_topics && !this.get('content.categoryName')) {
@@ -390,17 +391,19 @@ Discourse.ComposerView = Discourse.View.extend({
   }.property('content.categoryName'),
 
   replyValidation: function() {
-    var reply = this.get('content.reply'), reason;
-    if( !reply || reply.length < 1 ){
+    var replyLength = this.get('content.replyLength'),
+        missingChars = this.get('content.missingReplyCharacters'),
+        reason;
+    if( replyLength < 1 ){
       reason = Em.String.i18n('composer.error.post_missing');
-    } else if( reply.length < Discourse.SiteSettings.min_post_length ) {
-      reason = Em.String.i18n('composer.error.post_length', {min: Discourse.SiteSettings.min_post_length})
+    } else if( missingChars > 0 ) {
+      reason = Em.String.i18n('composer.error.post_length', {min: this.get('content.minimumPostLength')});
     }
 
     if( reason ) {
       return Discourse.InputValidation.create({ failed: true, reason: reason });
     }
-  }.property('content.reply')
+  }.property('content.reply', 'content.replyLength', 'content.missingReplyCharacters', 'content.minimumPostLength')
 });
 
 // not sure if this is the right way, keeping here for now, we could use a mixin perhaps
diff --git a/test/javascripts/fixtures/site_settings_fixtures.js b/test/javascripts/fixtures/site_settings_fixtures.js
index b6cb910767b..d107cb38772 100644
--- a/test/javascripts/fixtures/site_settings_fixtures.js
+++ b/test/javascripts/fixtures/site_settings_fixtures.js
@@ -1,2 +1,2 @@
 /*jshint maxlen:10000000 */
-Discourse.SiteSettings = {"title":"Discourse Meta","logo_url":"/assets/logo.png","logo_small_url":"/assets/logo-single.png","traditional_markdown_linebreaks":false,"top_menu":"latest|new|unread|read|favorited|categories","post_menu":"like|edit|flag|delete|share|bookmark|reply","share_links":"twitter|facebook|google+|email","track_external_right_clicks":false,"must_approve_users":false,"ga_tracking_code":"UA-33736483-2","ga_domain_name":"","enable_long_polling":true,"polling_interval":3000,"anon_polling_interval":30000,"min_post_length":20,"max_post_length":16000,"min_topic_title_length":15,"max_topic_title_length":255,"min_private_message_title_length":2,"allow_uncategorized_topics":true,"min_search_term_length":3,"flush_timings_secs":5,"supress_reply_directly_below":true,"email_domains_blacklist":"mailinator.com","email_domains_whitelist":null,"version_checks":true,"min_title_similar_length":10,"min_body_similar_length":15,"category_colors":"BF1E2E|F1592A|F7941D|9EB83B|3AB54A|12A89D|25AAE2|0E76BD|652D90|92278F|ED207B|8C6238|231F20|808281|B3B5B4|283890","max_upload_size_kb":1024,"category_featured_topics":6,"favicon_url":"/assets/favicon.ico","dynamic_favicon":false,"uncategorized_name":"uncategorized","uncategorized_color":"AB9364","uncategorized_text_color":"FFFFFF","invite_only":false,"login_required":false,"enable_local_logins":true,"enable_local_account_create":true,"enable_google_logins":true,"enable_yahoo_logins":true,"enable_twitter_logins":true,"enable_facebook_logins":true,"enable_cas_logins":false,"enable_github_logins":true,"enable_persona_logins":true,"educate_until_posts":2,"topic_views_heat_low":1000,"topic_views_heat_medium":2000,"topic_views_heat_high":5000};
\ No newline at end of file
+Discourse.SiteSettings = {"title":"Discourse Meta","logo_url":"/assets/logo.png","logo_small_url":"/assets/logo-single.png","traditional_markdown_linebreaks":false,"top_menu":"latest|new|unread|read|favorited|categories","post_menu":"like|edit|flag|delete|share|bookmark|reply","share_links":"twitter|facebook|google+|email","track_external_right_clicks":false,"must_approve_users":false,"ga_tracking_code":"UA-33736483-2","ga_domain_name":"","enable_long_polling":true,"polling_interval":3000,"anon_polling_interval":30000,"min_post_length":20,"max_post_length":16000,"min_topic_title_length":15,"max_topic_title_length":255,"min_private_message_title_length":2,"allow_uncategorized_topics":true,"min_search_term_length":3,"flush_timings_secs":5,"supress_reply_directly_below":true,"email_domains_blacklist":"mailinator.com","email_domains_whitelist":null,"version_checks":true,"min_title_similar_length":10,"min_body_similar_length":15,"category_colors":"BF1E2E|F1592A|F7941D|9EB83B|3AB54A|12A89D|25AAE2|0E76BD|652D90|92278F|ED207B|8C6238|231F20|808281|B3B5B4|283890","max_upload_size_kb":1024,"category_featured_topics":6,"favicon_url":"/assets/favicon.ico","dynamic_favicon":false,"uncategorized_name":"uncategorized","uncategorized_color":"AB9364","uncategorized_text_color":"FFFFFF","invite_only":false,"login_required":false,"enable_local_logins":true,"enable_local_account_create":true,"enable_google_logins":true,"enable_yahoo_logins":true,"enable_twitter_logins":true,"enable_facebook_logins":true,"enable_cas_logins":false,"enable_github_logins":true,"enable_persona_logins":true,"educate_until_posts":2,"topic_views_heat_low":1000,"topic_views_heat_medium":2000,"topic_views_heat_high":5000,"min_private_message_post_length":5};
\ No newline at end of file
diff --git a/test/javascripts/models/composer_test.js b/test/javascripts/models/composer_test.js
index 0987ecad704..4cf15fac0be 100644
--- a/test/javascripts/models/composer_test.js
+++ b/test/javascripts/models/composer_test.js
@@ -16,4 +16,25 @@ test('replyLength', function() {
   replyLength("1[quote=]not counted[/quote]2[quote=]at all[/quote]3", 3, "removes quotes");
   replyLength("1[quote=]not[quote=]counted[/quote]yay[/quote]2", 2, "handles nested quotes correctly");
 
-})
+});
+
+
+test('missingReplyCharacters', function() {
+  var missingReplyCharacters = function(val, isPM, expected, message) {
+    var composer = Discourse.Composer.create({ reply: val, creatingPrivateMessage: isPM });
+    equal(composer.get('missingReplyCharacters'), expected, message);
+  }
+
+  missingReplyCharacters('hi', false, Discourse.SiteSettings.min_post_length - 2, 'too short public post');
+  missingReplyCharacters('hi', true,  Discourse.SiteSettings.min_private_message_post_length - 2, 'too short private message');
+});
+
+test('missingTitleCharacters', function() {
+  var missingTitleCharacters = function(val, isPM, expected, message) {
+    var composer = Discourse.Composer.create({ title: val, creatingPrivateMessage: isPM });
+    equal(composer.get('missingTitleCharacters'), expected, message);
+  }
+
+  missingTitleCharacters('hi', false, Discourse.SiteSettings.min_topic_title_length - 2, 'too short post title');
+  missingTitleCharacters('z', true,  Discourse.SiteSettings.min_private_message_title_length - 1, 'too short pm title');
+});
\ No newline at end of file