diff --git a/README.md b/README.md
index 7e6e0c3..9fae795 100644
--- a/README.md
+++ b/README.md
@@ -35,6 +35,20 @@ Haml & HTML:
 <time datetime="PT3H30M" title="3 hours 30 minutes">about 4 hours</time>
 ```
 
+### helper `time_tag_interval`
+
+The same with `time_tag` but made for time intervals
+
+```haml
+= time_tag_interval Time.parse("14 March 1879"), Time.parse("18 April 1955"), :format => '%d %h %Y'
+= time_tag_interval Time.parse("14 March 1989"), 150.hours, :format => :short
+```
+
+```html
+<time datetime="1879-03-14T00:00:00+07:30/1955-04-18T00:00:00+07:30">14 Mar 1879 - 14 Mar 1879</time>
+<time datetime="1989-05-06T00:00:00+08:00/P6DT6H">06 May 00:00 in 6d 6h</time>
+```
+
 ### ActiveRecord::Base#html\_schema\_type
 
 ```ruby
diff --git a/lib/green_monkey/ext/view_helper.rb b/lib/green_monkey/ext/view_helper.rb
index 78abf12..7c69b3f 100644
--- a/lib/green_monkey/ext/view_helper.rb
+++ b/lib/green_monkey/ext/view_helper.rb
@@ -10,21 +10,51 @@ module ViewHelper
     # = time_tag post.created_at
     # = time_tag post.created_at, format: "%d %h %Y %R%p"
     # = time_tag post.created_at, itemprop: "datePublished"
-    def time_tag(date_or_time, *args)
+    def time_tag(time, *args)
       options  = args.extract_options!
       format   = options.delete(:format) || :long
+      datetime = time_to_iso8601(time)
       
-      if date_or_time.acts_like?(:time)
+      
+      if time.acts_like?(:time)
         title = nil
-        content  = args.first || I18n.l(date_or_time, format: format)
-        datetime = date_or_time.iso8601(10)
-      elsif date_or_time.kind_of?(Numeric)
-        title = ChronicDuration.output(date_or_time, :format => format)
-        content = distance_of_time_in_words(date_or_time)
-        datetime = ChronicDuration.output(date_or_time, :format => :iso8601)
+        content  = args.first || I18n.l(time, format: format)
+      elsif time.kind_of?(Numeric)
+        title = ChronicDuration.output(time, :format => format)
+        content = args.first || distance_of_time_in_words(time)
       end
       
       content_tag(:time, content, options.reverse_merge(datetime: datetime, title: title))
     end
+    
+    def time_tag_interval(from, to, *args)
+      options  = args.extract_options!
+      format   = options.delete(:format) || :long
+      
+      datetime = [from, to].map(&method(:time_to_iso8601)).join("/")
+      content  = args.first || [from, to].map do |time|
+        if time.acts_like?(:time)
+          I18n.l(from, format: format)
+        else
+          ChronicDuration.output(time, :format => format)
+        end
+      end
+      
+      if to.acts_like?(:time)
+        content = content.join(" - ")
+      else
+        content = content.join(" in ")
+      end
+      
+      content_tag(:time, content, options.reverse_merge(datetime: datetime))
+    end
+    
+    def time_to_iso8601(time)
+      if time.acts_like?(:time)
+        time.iso8601
+      elsif time.kind_of?(Numeric)
+        ChronicDuration.output(time, :format => :iso8601)
+      end
+    end
   end
 end
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diff --git a/spec/haml_spec.rb b/spec/haml_spec.rb
index a80aa46..4ad4ace 100644
--- a/spec/haml_spec.rb
+++ b/spec/haml_spec.rb
@@ -34,22 +34,6 @@ def render_haml(template, options = {})
     render_haml("%b[:title] Dada").should =~ /itemprop=.?title/
   end
   
-  it "should run time_tag with time" do
-    time = Time.now
-    str = render_haml("= time_tag(time)", time: time)
-    
-    str.should =~ /<time.+datetime=.?#{Regexp.escape time.iso8601(10)}/
-  end
-  
-  it "should run time_tag with duration" do
-    str = render_haml("= time_tag(time)", time: 3.hours + 30.minutes)
-    str.should =~ /datetime=.PT3H30M/
-  end
-  
-  it "should run time_tag with time interval" do
-    # TODO
-  end
-  
   it "should generate valid microdata layout" do
     post = Post.create(title: "Post 1", body: "Some text")
     tpl = Pathname.new(__FILE__).dirname.join("post.haml")
@@ -66,4 +50,36 @@ def render_haml(template, options = {})
     doc.items[0].id.should == post.id.to_s
     doc.items[0].type.should == post.html_schema_type.itemtype.source
   end
+  
+  describe 'time_tag' do
+    it "should produce itemprop if specified" do
+      str = render_haml("= time_tag(Time.now, itemprop: 'time')")
+      str.should =~ /itemprop="time"/
+    end
+    
+    it "should run with time" do
+      time = Time.now
+      str = render_haml("= time_tag(time)", time: time)
+
+      str.should =~ /<time.+datetime=.?#{Regexp.escape time.iso8601}/
+    end
+
+    it "should run with duration" do
+      str = render_haml("= time_tag(time)", time: 3.hours + 30.minutes)
+      str.should =~ /datetime=.PT3H30M/
+    end
+
+    it "should run with time interval of 2 dates" do
+      time = [Time.parse("14 March 1879"), Time.parse("18 April 1955")]
+
+      str = render_haml("= time_tag_interval(*time, :format => '%d %h %Y')", time: time)
+      str.should =~ /<time.+datetime=.?#{Regexp.escape time[0].iso8601}\/#{Regexp.escape time[1].iso8601}/
+    end
+
+    it "should run with date and duration" do
+      time = [Time.parse("6 May 1989"), 150.hours]
+      str = render_haml("= time_tag_interval(*time, :format => :short)", time: time)
+      str.should =~ /<time.+datetime=.?#{Regexp.escape time[0].iso8601}\/P6DT6H/
+    end
+  end
 end
\ No newline at end of file