diff --git a/private_dot_config/zsh/dot_zshrc b/private_dot_config/zsh/dot_zshrc
index 37ca165..2f6c8c5 100644
--- a/private_dot_config/zsh/dot_zshrc
+++ b/private_dot_config/zsh/dot_zshrc
@@ -118,7 +118,11 @@ PROMPT_PAD="."
 PROMPT_EXTRA_WIDTH=73
 
 precmd() {
+  if [ -z ${STARTCMD_TS+x} ]; then
+    STARTCMD_TS=$(date +%s%N)
+  fi
   local prompt_ln="${#${${PWD}/${HOME}/~}}" # len of path where $HOME is susbtiued by ~ (and is counted as 1)
+  
   if (($COLUMNS > PROMPT_EXTRA_WIDTH + prompt_ln)); then
     local exec_ts=$(($(date +%s%N) - STARTCMD_TS))
     local seconds=$(echo "scale=9; $exec_ts / 1000000000" | bc)