diff --git a/autoload/airline.vim b/autoload/airline.vim
index 549c2a9..208fa2c 100644
--- a/autoload/airline.vim
+++ b/autoload/airline.vim
@@ -196,6 +196,7 @@ function! airline#check_mode(winnr)
   if get(w:, 'airline_lastmode', '') != mode_string
     call airline#highlighter#highlight_modified_inactive(context.bufnr)
     call airline#highlighter#highlight(l:mode, context.bufnr)
+    silent doautocmd User AirlineModeChanged
     let w:airline_lastmode = mode_string
   endif
 
diff --git a/autoload/airline/extensions/wordcount.vim b/autoload/airline/extensions/wordcount.vim
index 0a8988c..7486929 100644
--- a/autoload/airline/extensions/wordcount.vim
+++ b/autoload/airline/extensions/wordcount.vim
@@ -1,43 +1,114 @@
 " MIT License. Copyright (c) 2013-2018 Bailey Ling et al.
-" vim: et ts=2 sts=2 sw=2
+" vim: et ts=2 sts=2 sw=2 fdm=marker
 
 scriptencoding utf-8
 
-let s:formatter = get(g:, 'airline#extensions#wordcount#formatter', 'default')
-let g:airline#extensions#wordcount#filetypes = get(g:, 'airline#extensions#wordcount#filetypes',
-      \ '\vhelp|markdown|rst|org|text|asciidoc|tex|mail')
+" get wordcount {{{1
+if exists('*wordcount')
+  function! s:get_wordcount(visual_mode_active)
+    let query = a:visual_mode_active ? 'visual_words' : 'words'
+    return string(wordcount()[query])
+  endfunction
+else
+  function! s:get_wordcount(visual_mode_active)
+    " index to retrieve from whitespace-separated output of g_CTRL-G
+    " 11 : words, 5 : visual words (in visual mode)
+    let idx = a:visual_mode_active ? 5 : 11
 
-function! s:wordcount_update()
-  if empty(bufname(''))
-    return
-  endif
-  if match(&ft, get(g:, 'airline#extensions#wordcount#filetypes')) > -1
-    let l:mode = mode()
-    if l:mode ==# 'v' || l:mode ==# 'V' || l:mode ==# 's' || l:mode ==# 'S'
-      let b:airline_wordcount = airline#extensions#wordcount#formatters#{s:formatter}#format()
-      let b:airline_change_tick = b:changedtick
-    else
-      if get(b:, 'airline_wordcount_cache', '') is# '' ||
-            \ b:airline_wordcount_cache isnot# get(b:, 'airline_wordcount', '') ||
-            \ get(b:, 'airline_change_tick', 0) != b:changedtick || 
-            \ get(b:, 'airline_winwidth', 0) != winwidth(0)
-        " cache data
-        let b:airline_wordcount = airline#extensions#wordcount#formatters#{s:formatter}#format()
-        let b:airline_wordcount_cache = b:airline_wordcount
-        let b:airline_change_tick = b:changedtick
-        let b:airline_winwidth = winwidth(0)
-      endif
+    let save_status = v:statusmsg
+    execute "silent normal! g\<cn-g>"
+    let stat = v:statusmsg
+    let v:statusmsg = save_status
+
+    let parts = split(stat)
+    if len(parts) > idx
+      return parts[idx]
     endif
+  endfunction
+endif
+
+" format {{{1
+let s:formatter = get(g:, 'airline#extensions#wordcount#formatter', 'default')
+
+" wrapper function for compatibility; redefined below for old-style formatters
+function! s:format_wordcount(wordcount)
+  return airline#extensions#wordcount#formatters#{s:formatter}#to_string(a:wordcount)
+endfunction
+
+" check user-defined formatter exists with appropriate functions, otherwise
+" fall back to default
+if s:formatter !=# 'default'
+  execute 'runtime! autoload/airline/extensions/wordcount/formatters/'.s:formatter
+  if !exists('*airline#extensions#wordcount#formatters#{s:formatter}#to_string')
+    if !exists('*airline#extensions#wordcount#formatters#{s:formatter}#format')
+      let s:formatter = 'default'
+    else
+      " redefine for backwords compatibility
+      function! s:format_wordcount(_)
+        if mode() ==? 'v'
+          return b:airline_wordcount
+        else
+          return airline#extensions#wordcount#formatters#{s:formatter}#format()
+        endif
+      endfunction
+    endif
+  endif
+endif
+
+" update {{{1
+let s:wordcount_cache = 0  " cache wordcount for performance when force_update=0
+function! s:update_wordcount(force_update)
+  let wordcount = s:get_wordcount(0)
+  if wordcount != s:wordcount_cache || a:force_update
+    let s:wordcount_cache = wordcount
+    let b:airline_wordcount =  s:format_wordcount(wordcount)
   endif
 endfunction
 
+let s:visual_active = 0  " Boolean: for when to get visual wordcount
+function airline#extensions#wordcount#get()
+  if s:visual_active
+    return s:format_wordcount(s:get_wordcount(1))
+  else
+    if b:airline_changedtick != b:changedtick
+      call s:update_wordcount(0)
+      let b:airline_changedtick = b:changedtick
+    endif
+    return b:airline_wordcount
+  endif
+endfunction
+
+" airline functions {{{1
+" default filetypes:
+let s:filetypes = ['help', 'markdown', 'rst', 'org', 'text', 'asciidoc', 'tex', 'mail']
 function! airline#extensions#wordcount#apply(...)
-  if match(&ft, get(g:, 'airline#extensions#wordcount#filetypes')) > -1
-    call airline#extensions#prepend_to_section('z', '%{get(b:, "airline_wordcount", "")}')
+  let filetypes = get(g:, 'airline#extensions#wordcount#filetypes', s:filetypes)
+
+  " Check if filetype needs testing
+  if did_filetype() || filetypes isnot s:filetypes
+    let s:filetypes = filetypes
+
+    " Select test based on type of "filetypes": new=list, old=string
+    if type(filetypes) == v:t_list
+          \ ? index(filetypes, &filetype) > -1 || index(filetypes, 'all') > -1
+          \ : match(&filetype, filetypes) > -1
+      let b:airline_changedtick = -1
+      call s:update_wordcount(1) " force update: ensures initial worcount exists
+    elseif exists('b:airline_wordcount') " cleanup when filetype is removed
+      unlet b:airline_wordcount
+    endif
+  endif
+
+  if exists('b:airline_wordcount')
+    call airline#extensions#prepend_to_section(
+          \ 'z', '%{airline#extensions#wordcount#get()}')
   endif
 endfunction
 
 function! airline#extensions#wordcount#init(ext)
+  augroup airline_wordcount
+    autocmd! User AirlineModeChanged nested
+          \ let s:visual_active = (mode() ==? 'v' || mode() ==? 's')
+  augroup END
   call a:ext.add_statusline_func('airline#extensions#wordcount#apply')
-  autocmd BufReadPost,CursorMoved,CursorMovedI * call s:wordcount_update()
 endfunction
diff --git a/autoload/airline/extensions/wordcount/formatters/default.vim b/autoload/airline/extensions/wordcount/formatters/default.vim
index d7b5fae..a2b3935 100644
--- a/autoload/airline/extensions/wordcount/formatters/default.vim
+++ b/autoload/airline/extensions/wordcount/formatters/default.vim
@@ -3,64 +3,39 @@
 
 scriptencoding utf-8
 
-function! airline#extensions#wordcount#formatters#default#format()
-  let fmt = get(g:, 'airline#extensions#wordcount#formatter#default#fmt', '%s words')
-  let fmt_short = get(g:, 'airline#extensions#wordcount#formatter#default#fmt_short', fmt == '%s words' ? '%sW' : fmt)
-  let words = string(s:wordcount())
-  if empty(words)
+function s:update_fmt(...)
+  let s:fmt = get(g:, 'airline#extensions#wordcount#formatter#default#fmt', '%s words')
+  let s:fmt_short = get(g:, 'airline#extensions#wordcount#formatter#default#fmt_short', s:fmt == '%s words' ? '%sW' : s:fmt)
+endfunction
+
+" Reload format when statusline is rebuilt
+call s:update_fmt()
+call airline#add_statusline_funcref(function('s:update_fmt'))
+
+if match(get(v:, 'lang', ''), '\v\cC|en') > -1
+  let s:decimal_group = ','
+elseif match(get(v:, 'lang', ''), '\v\cde|dk|fr|pt') > -1
+  let s:decimal_group = '.'
+else
+  let s:decimal_group = ''
+endif
+
+function! airline#extensions#wordcount#formatters#default#to_string(wordcount)
+  if empty(a:wordcount)
     return
   endif
-  let result = g:airline_symbols.space . g:airline_right_alt_sep . g:airline_symbols.space
+
   if winwidth(0) >= 80
-    let separator = s:get_decimal_group()
-    if words > 999 && !empty(separator)
+    if a:wordcount > 999
       " Format number according to locale, e.g. German: 1.245 or English: 1,245
-      let words = substitute(words, '\d\@<=\(\(\d\{3\}\)\+\)$', separator.'&', 'g')
-    endif
-    let result = printf(fmt, words). result
-  else
-    let result = printf(fmt_short, words). result
-  endif
-  return result
-endfunction
-
-function! s:wordcount()
-  if exists("*wordcount")
-    let l:mode = mode()
-    if l:mode ==# 'v' || l:mode ==# 'V' || l:mode ==# 's' || l:mode ==# 'S'
-      let l:visual_words = wordcount()['visual_words']
-      if l:visual_words != ''
-        return l:visual_words
-      else
-        return 0
-      endif
+      let wordcount = substitute(a:wordcount, '\d\@<=\(\(\d\{3\}\)\+\)$', s:decimal_group.'&', 'g')
     else
-      return wordcount()['words']
+      let wordcount = a:wordcount
     endif
-  elseif mode() =~? 's'
-    return
+    let str = printf(s:fmt, wordcount)
   else
-    let old_status = v:statusmsg
-    let position = getpos(".")
-    exe "silent normal! g\<c-g>"
-    let stat = v:statusmsg
-    call setpos('.', position)
-    let v:statusmsg = old_status
-
-    let parts = split(stat)
-    if len(parts) > 11
-      return str2nr(parts[11])
-    else
-      return
-    endif
+    let str = printf(s:fmt_short, a:wordcount)
   endif
+  return str . g:airline_symbols.space . g:airline_right_alt_sep . g:airline_symbols.space
 endfunction
 
-function! s:get_decimal_group()
-  if match(get(v:, 'lang', ''), '\v\cC|en') > -1
-    return ','
-  elseif match(get(v:, 'lang', ''), '\v\cde|dk|fr|pt') > -1
-    return '.'
-  endif
-  return ''
-endfunction