diff --git a/install b/install
index a3a36ba..963d441 100755
--- a/install
+++ b/install
@@ -115,14 +115,14 @@ __fsel() {
 }
 
 __fsel_tmux() {
-  local height lines
+  local height
   height=${FZF_TMUX_HEIGHT:-40%}
-  lines=${LINES:-40}
   if [[ $height =~ %$ ]]; then
-    height=${height:0:${#height}-1}
-    height=$(( height * lines / 100 ))
+    height="-p ${height%\%}"
+  else
+    height="-l $height"
   fi
-  tmux split-window -l $height "tmux send-keys -t $TMUX_PANE \"\$($__fsel)\""
+  tmux split-window $height "tmux send-keys -t $TMUX_PANE \"\$($__fsel)\""
 }
 
 __fcd() {
@@ -189,14 +189,14 @@ EOF
 
 if [ -n "$TMUX_PANE" -a ${FZF_TMUX:-1} -ne 0 -a ${LINES:-40} -gt 15 ]; then
   fzf-file-widget() {
-    local height lines
+    local height
     height=${FZF_TMUX_HEIGHT:-40%}
-    lines=${LINES:-40}
     if [[ $height =~ %$ ]]; then
-      height=${height:0:${#height}-1}
-      height=$(( height * lines / 100 ))
+      height="-p ${height%\%}"
+    else
+      height="-l $height"
     fi
-    tmux split-window -l $height "tmux send-keys -t $TMUX_PANE \"\$($__fsel)\""
+    tmux split-window $height "tmux send-keys -t $TMUX_PANE \"\$($__fsel)\""
   }
 else
   fzf-file-widget() {
diff --git a/plugin/fzf.vim b/plugin/fzf.vim
index c75e9af..faf8e57 100644
--- a/plugin/fzf.vim
+++ b/plugin/fzf.vim
@@ -115,20 +115,16 @@ function! s:execute_tmux(dict, command, temps)
     let command = a:command
   endif
 
-  if type(a:dict.tmux) == 1
-    if a:dict.tmux =~ '%$'
-      let height = &lines * str2nr(a:dict.tmux[0:-2]) / 100
-    else
-      let height = str2nr(a:dict.tmux)
-    endif
+  if type(a:dict.tmux) == 1 && a:dict.tmux =~ '%$'
+    let height = '-p '.a:dict.tmux[0:-2]
   else
-    let height = a:dict.tmux
+    let height = '-l '.a:dict.tmux
   endif
 
   let s:pane = substitute(
     \ system(
       \ printf(
-        \ 'tmux split-window -l %d -P -F "#{pane_id}" %s',
+        \ 'tmux split-window %s -P -F "#{pane_id}" %s',
         \ height, s:shellesc(command))), '\n', '', 'g')
   let s:dict = a:dict
   let s:temps = a:temps