diff --git a/README.md b/README.md
index d8ee436..a0c718a 100644
--- a/README.md
+++ b/README.md
@@ -82,7 +82,7 @@ $ git clone https://github.com/borgbase/ansible-role-borgbackup.git roles/ansibl
 - `borgmatic_cron_checks_day`: Day when cron job for infrequent checks will run. Defaults to `{{ 28 | random }}`
 - `borgmatic_cron_checks_hour`: Hour when cron job for infrequent checks will run. Defaults to `{{ range(7, 24) | random }}`
 - `borgmatic_cron_checks_minute`: Minute when cron job for infrequent checks will run. Defaults to  `{{ 59 | random }}`
-- `borg_archive_name_format`: The format for the archive name, e.g. `{hostname}-{now:%Y-%m-%dT%H:%M:%S.%f}`. Defaults to `{hostname}-{now}`
+- `borg_archive_name_format`: The format for the archive name, e.g. `{hostname}-{now:%Y-%m-%dT%H:%M:%S.%f}`. Defaults to `{hostname}-{now:%Y-%m-%d-%H%M%S}`
 - `borg_prune_prefix`: The prefix used to select archives to prune. Defaults to `{hostname}-`
 - `borg_check_prefix`: The prefix used to select archives to check for consistency. Defaults to `{hostname}-`
 
diff --git a/defaults/main.yml b/defaults/main.yml
index 55ac7da..d790e59 100755
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -44,6 +44,6 @@ borgmatic_cron_checks_day: "{{ range(1, 28) | random(seed=inventory_hostname) }}
 borgmatic_cron_checks_hour: "{{ range(9, 24) | random(seed=inventory_hostname) }}"
 borgmatic_cron_checks_minute: "{{ 59 | random(seed=inventory_hostname) }}"
 # the following are optional and defined by the user as needed
-# borg_archive_name_format: '{hostname}-{now}'
+# borg_archive_name_format: '{hostname}-{now:%Y-%m-%d-%H%M%S}'
 # borg_prune_prefix: '{hostname}-'
 # borg_check_prefix: '{hostname}-'
diff --git a/templates/config.yaml.j2 b/templates/config.yaml.j2
index 5d5810f..261bcfc 100644
--- a/templates/config.yaml.j2
+++ b/templates/config.yaml.j2
@@ -97,7 +97,7 @@ storage:
 {% if borg_archive_name_format is defined %}
     archive_name_format: '{{ borg_archive_name_format | replace("'", "") }}'
 {% elif borg_prune_prefix is defined %}
-    archive_name_format: '{{ borg_prune_prefix | replace("'", "") }}-{now}'
+    archive_name_format: '{{ borg_prune_prefix | replace("'", "") }}-{now:%Y-%m-%d-%H%M%S}'
 {% else %}
     archive_name_format: '{hostname}-{now:%Y-%m-%d-%H%M%S}'
 {% endif %}