diff --git a/lib/jekyll-compose.rb b/lib/jekyll-compose.rb
index 7f2114d..dd41ca5 100644
--- a/lib/jekyll-compose.rb
+++ b/lib/jekyll-compose.rb
@@ -13,6 +13,8 @@ module Compose
     DEFAULT_TYPE = "md"
     DEFAULT_LAYOUT = "post"
     DEFAULT_LAYOUT_PAGE = "page"
+    DEFAULT_DATESTAMP_FORMAT = "%Y-%m-%d"
+    DEFAULT_TIMESTAMP_FORMAT = "%Y-%m-%d %H:%M %z"
   end
 end
 
diff --git a/lib/jekyll/commands/post.rb b/lib/jekyll/commands/post.rb
index 8817b05..18a88d2 100644
--- a/lib/jekyll/commands/post.rb
+++ b/lib/jekyll/commands/post.rb
@@ -56,11 +56,11 @@ def file_name
         end
 
         def _date_stamp
-          @params.date.strftime "%Y-%m-%d"
+          @params.date.strftime Jekyll::Compose::DEFAULT_DATESTAMP_FORMAT
         end
 
         def _time_stamp
-          @params.date.strftime("%Y-%m-%d %H:%M %z")
+          @params.date.strftime Jekyll::Compose::DEFAULT_TIMESTAMP_FORMAT
         end
 
         def content(custom_front_matter = {})
diff --git a/lib/jekyll/commands/publish.rb b/lib/jekyll/commands/publish.rb
index 796d690..2ddedff 100644
--- a/lib/jekyll/commands/publish.rb
+++ b/lib/jekyll/commands/publish.rb
@@ -55,7 +55,7 @@ def from
       end
 
       def to
-        date_stamp = params.date.strftime "%Y-%m-%d"
+        date_stamp = params.date.strftime Jekyll::Compose::DEFAULT_DATESTAMP_FORMAT
         "_posts/#{date_stamp}-#{params.name}"
       end
     end
diff --git a/spec/post_spec.rb b/spec/post_spec.rb
index 7e41db7..977be38 100644
--- a/spec/post_spec.rb
+++ b/spec/post_spec.rb
@@ -4,8 +4,8 @@
   let(:name) { "A test post" }
   let(:args) { [name] }
   let(:posts_dir) { Pathname.new source_dir("_posts") }
-  let(:datestamp) { Time.now.strftime("%Y-%m-%d") }
-  let(:timestamp) { Time.now.strftime("%Y-%m-%d %H:%M %z") }
+  let(:datestamp) { Time.now.strftime(Jekyll::Compose::DEFAULT_DATESTAMP_FORMAT) }
+  let(:timestamp) { Time.now.strftime(Jekyll::Compose::DEFAULT_TIMESTAMP_FORMAT) }
   let(:filename) { "#{datestamp}-a-test-post.md" }
   let(:path) { posts_dir.join(filename) }
 
@@ -68,7 +68,7 @@
 
   context "when the post already exists" do
     let(:name) { "An existing post" }
-    let(:filename) { "#{Time.now.strftime("%Y-%m-%d")}-an-existing-post.md" }
+    let(:filename) { "#{Time.now.strftime(Jekyll::Compose::DEFAULT_DATESTAMP_FORMAT)}-an-existing-post.md" }
 
     before(:each) do
       FileUtils.touch path
diff --git a/spec/publish_spec.rb b/spec/publish_spec.rb
index f49c9aa..1744db6 100644
--- a/spec/publish_spec.rb
+++ b/spec/publish_spec.rb
@@ -4,7 +4,7 @@
   let(:drafts_dir) { Pathname.new source_dir("_drafts") }
   let(:posts_dir)  { Pathname.new source_dir("_posts") }
   let(:draft_to_publish) { "a-test-post.md" }
-  let(:datestamp) { Time.now.strftime("%Y-%m-%d") }
+  let(:datestamp) { Time.now.strftime(Jekyll::Compose::DEFAULT_DATESTAMP_FORMAT) }
   let(:post_filename) { "#{datestamp}-#{draft_to_publish}" }
   let(:args) { ["_drafts/#{draft_to_publish}"] }