diff --git a/rc/bashrc b/rc/bashrc
index 0bfd3a63..d4709c67 100644
--- a/rc/bashrc
+++ b/rc/bashrc
@@ -534,8 +534,10 @@ alias reset-xfce4="rm -rf ~/.config/xfce4"
 alias reset-matepanel="mate-panel --reset"
 
 # Show date in ISO 8601 format
-alias isodate='date "+%Y-%m-%d %H:%M:%S%z"'
-alias isodateu='date -u "+%Y-%m-%d %H:%M:%S%z"'
+alias isodate='date -Is'
+alias isodateu='date -uIs'
+alias isodatea='date "+%Y-%m-%dT%H:%M:%S%z"'
+alias isodateua='date -u "+%Y-%m-%dT%H:%M:%S%z"'
 
 # Show information on PEM file.
 alias peminfo="openssl x509 -text -in"
diff --git a/rc/zshrc b/rc/zshrc
index 2b85d47e..dfa14528 100644
--- a/rc/zshrc
+++ b/rc/zshrc
@@ -509,8 +509,10 @@ alias reset-xfce4="rm -rf ~/.config/xfce4"
 alias reset-matepanel="mate-panel --reset"
 
 # Show date in ISO 8601 format
-alias isodate='date "+%Y-%m-%d %H:%M:%S%z"'
-alias isodateu='date -u "+%Y-%m-%d %H:%M:%S%z"'
+alias isodate='date -Is'
+alias isodateu='date -uIs'
+alias isodatea='date "+%Y-%m-%dT%H:%M:%S%z"'
+alias isodateua='date -u "+%Y-%m-%dT%H:%M:%S%z"'
 
 # Show information on PEM file.
 alias peminfo="openssl x509 -text -in"