diff --git a/exampleSite/config.toml b/exampleSite/config.toml
index 78ffb75..43cd18b 100644
--- a/exampleSite/config.toml
+++ b/exampleSite/config.toml
@@ -19,8 +19,8 @@ hasCJKLanguage = true
         Profiles, backgrounds, favorite things etc.
     """
     publicationYear = "2019"
-    listPageDateFormat = "January, 2006" # See https://gohugo.io/functions/format/
-    singlePageDateFormat = "January 2, 2006"
+    # listPageDateFormat = "January, 2006" # See https://gohugo.io/functions/format/
+    # singlePageDateFormat = "January 2, 2006"
     # custom_css = ["/css/custom.css"]
     # custom_js = ["/js/custom.js"]
 
diff --git a/layouts/_default/list.html b/layouts/_default/list.html
index fb53e88..f98242d 100644
--- a/layouts/_default/list.html
+++ b/layouts/_default/list.html
@@ -9,7 +9,8 @@
   <div id="searchResults"></div>
   <!-- contents -->
   <div id="contentsList">
-    {{ range $index, $value := .Pages.GroupByDate .Site.Params.listPageDateFormat }}
+    {{ $listPageDateFormat := .Site.Params.listPageDateFormat | default "January, 2006"}}
+    {{ range $index, $value := .Pages.GroupByDate $listPageDateFormat }}
     {{ if (ne $index 0) }}
     <hr class="separator">
     {{ end }}
diff --git a/layouts/_default/single.html b/layouts/_default/single.html
index 8e89719..ea6919a 100644
--- a/layouts/_default/single.html
+++ b/layouts/_default/single.html
@@ -2,7 +2,8 @@
   <h1>{{ .Title }}</h1>
   {{ partial "header.html" . }}
   <!-- date -->
-  <p class="date">{{ .Date.Format .Site.Params.singlePageDateFormat }}</p>
+  {{ $singlePageDateFormat := .Site.Params.singlePageDateFormat | default "January 2, 2006"}}
+  <p class="date">{{ .Date.Format $singlePageDateFormat }}</p>
   <!-- content -->
   <div id="contentBody">
     {{ .Content }}