diff --git a/src/strings.c b/src/strings.c
index bc88ce5..847d743 100644
--- a/src/strings.c
+++ b/src/strings.c
@@ -2143,27 +2143,22 @@
 		    }
 		    if (fmt_spec == 'S')
 		    {
-			size_t base_width = min_field_width;
-			size_t pad_cell = 0;
+			char_u	*p1;
+			size_t	i;
+			int	cell;
 
-			if (precision)
-			{
-			    char_u  *p1;
-			    size_t  i = 0;
-
-			    for (p1 = (char_u *)str_arg; *p1;
+			for (i = 0, p1 = (char_u *)str_arg; *p1;
 							  p1 += mb_ptr2len(p1))
-			    {
-				i += (size_t)mb_ptr2cells(p1);
-				if (i > precision)
-				    break;
-			    }
-			    pad_cell = min_field_width - precision;
-			    base_width = str_arg_l = precision =
-							p1 - (char_u *)str_arg;
+			{
+			    cell = mb_ptr2cells(p1);
+			    if (precision_specified && i + cell > precision)
+				break;
+			    i += cell;
 			}
+
+			str_arg_l = p1 - (char_u *)str_arg;
 			if (min_field_width != 0)
-			    min_field_width = base_width + pad_cell;
+			    min_field_width += str_arg_l - i;
 		    }
 		    break;
 
diff --git a/src/testdir/test_expr.vim b/src/testdir/test_expr.vim
index 9700974..323ce26 100644
--- a/src/testdir/test_expr.vim
+++ b/src/testdir/test_expr.vim
@@ -302,6 +302,66 @@
   call assert_equal('[あいうえお]', printf('[%10.10S]', 'あいうえお'))
   call assert_equal('[あいうえお]', printf('[%10.12S]', 'あいうえお'))
 
+  call assert_equal('あいう', printf('%S', 'あいう'))
+  call assert_equal('あいう', printf('%#S', 'あいう'))
+
+  call assert_equal('あb', printf('%2S', 'あb'))
+  call assert_equal('あb', printf('%.4S', 'あb'))
+  call assert_equal('あ', printf('%.2S', 'あb'))
+  call assert_equal(' あb', printf('%4S', 'あb'))
+  call assert_equal('0あb', printf('%04S', 'あb'))
+  call assert_equal('あb ', printf('%-4S', 'あb'))
+  call assert_equal('あ  ', printf('%-4.2S', 'あb'))
+
+  call assert_equal('aい', printf('%2S', 'aい'))
+  call assert_equal('aい', printf('%.4S', 'aい'))
+  call assert_equal('a', printf('%.2S', 'aい'))
+  call assert_equal(' aい', printf('%4S', 'aい'))
+  call assert_equal('0aい', printf('%04S', 'aい'))
+  call assert_equal('aい ', printf('%-4S', 'aい'))
+  call assert_equal('a   ', printf('%-4.2S', 'aい'))
+
+  call assert_equal('[あいう]', printf('[%05S]', 'あいう'))
+  call assert_equal('[あいう]', printf('[%06S]', 'あいう'))
+  call assert_equal('[0あいう]', printf('[%07S]', 'あいう'))
+
+  call assert_equal('[あiう]', printf('[%05S]', 'あiう'))
+  call assert_equal('[0あiう]', printf('[%06S]', 'あiう'))
+  call assert_equal('[00あiう]', printf('[%07S]', 'あiう'))
+
+  call assert_equal('[0あい]', printf('[%05.4S]', 'あいう'))
+  call assert_equal('[00あい]', printf('[%06.4S]', 'あいう'))
+  call assert_equal('[000あい]', printf('[%07.4S]', 'あいう'))
+
+  call assert_equal('[00あi]', printf('[%05.4S]', 'あiう'))
+  call assert_equal('[000あi]', printf('[%06.4S]', 'あiう'))
+  call assert_equal('[0000あi]', printf('[%07.4S]', 'あiう'))
+
+  call assert_equal('[0あい]', printf('[%05.5S]', 'あいう'))
+  call assert_equal('[00あい]', printf('[%06.5S]', 'あいう'))
+  call assert_equal('[000あい]', printf('[%07.5S]', 'あいう'))
+
+  call assert_equal('[あiう]', printf('[%05.5S]', 'あiう'))
+  call assert_equal('[0あiう]', printf('[%06.5S]', 'あiう'))
+  call assert_equal('[00あiう]', printf('[%07.5S]', 'あiう'))
+
+  call assert_equal('[0000000000]', printf('[%010.0S]', 'あいう'))
+  call assert_equal('[0000000000]', printf('[%010.1S]', 'あいう'))
+  call assert_equal('[00000000あ]', printf('[%010.2S]', 'あいう'))
+  call assert_equal('[00000000あ]', printf('[%010.3S]', 'あいう'))
+  call assert_equal('[000000あい]', printf('[%010.4S]', 'あいう'))
+  call assert_equal('[000000あい]', printf('[%010.5S]', 'あいう'))
+  call assert_equal('[0000あいう]', printf('[%010.6S]', 'あいう'))
+  call assert_equal('[0000あいう]', printf('[%010.7S]', 'あいう'))
+
+  call assert_equal('[0000000000]', printf('[%010.1S]', 'あiう'))
+  call assert_equal('[00000000あ]', printf('[%010.2S]', 'あiう'))
+  call assert_equal('[0000000あi]', printf('[%010.3S]', 'あiう'))
+  call assert_equal('[0000000あi]', printf('[%010.4S]', 'あiう'))
+  call assert_equal('[00000あiう]', printf('[%010.5S]', 'あiう'))
+  call assert_equal('[00000あiう]', printf('[%010.6S]', 'あiう'))
+  call assert_equal('[00000あiう]', printf('[%010.7S]', 'あiう'))
+
   call assert_equal('1%', printf('%d%%', 1))
 endfunc
 
diff --git a/src/version.c b/src/version.c
index 58a1856..b4e2464 100644
--- a/src/version.c
+++ b/src/version.c
@@ -758,6 +758,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3663,
+/**/
     3662,
 /**/
     3661,