diff --git a/autoload/easy_align.vim b/autoload/easy_align.vim
index d5a2576..0cc3147 100644
--- a/autoload/easy_align.vim
+++ b/autoload/easy_align.vim
@@ -67,9 +67,9 @@ let s:shorthand = {
 \ 'mode_sequence': 'm',  'ignores':          'ig', 'filter':          'f'
 \ }
 
-if exists("*strwidth")
+if exists("*strdisplaywidth")
   function! s:strwidth(str)
-    return strwidth(a:str) + len(matchstr(a:str, '^\t*')) * (&tabstop - 1)
+    return strdisplaywidth(a:str)
   endfunction
 else
   function! s:strwidth(str)
diff --git a/test/fixed.vader b/test/fixed.vader
index 01145c9..538bf2b 100644
--- a/test/fixed.vader
+++ b/test/fixed.vader
@@ -117,4 +117,26 @@ Expect:
   		n2gv = {}
   		n2vt = {}
 
+Given (Tab-indented code (#20)):
+  class MyUnitTest(unittest.TestCase):
+  	def test_base(self):
+  	# 	n2f= {}
+  	## 	n2v= {}
+  	# 	f2v = {}
+  	## 	n2gv  = {}
+  	# 	n2vt   = {}
+
+Execute:
+  set tabstop=12
+  %EasyAlign=
+
+Expect:
+  class MyUnitTest(unittest.TestCase):
+  	def test_base(self):
+  	# 	n2f  = {}
+  	## 	n2v  = {}
+  	# 	f2v  = {}
+  	## 	n2gv = {}
+  	# 	n2vt = {}
+
 Include: include/teardown.vader