diff --git a/src/adw-length-unit.c b/src/adw-length-unit.c
index d7d356360d0fd450bc256f05ab97e71dde4a44f6..136e720c623bf7d9a36978172706f1e64a4b7690 100644
--- a/src/adw-length-unit.c
+++ b/src/adw-length-unit.c
@@ -36,6 +36,9 @@ get_dpi (GtkSettings *settings)
 
   g_object_get (settings, "gtk-xft-dpi", &xft_dpi, NULL);
 
+  if (xft_dpi == 0)
+    xft_dpi = 96 * PANGO_SCALE;
+
   return xft_dpi / PANGO_SCALE;
 }
 
diff --git a/src/adw-tab-button.c b/src/adw-tab-button.c
index de54074e61dfd7e24f3bb77ca0e413fc41e9f8bd..b736400579db54c311ac5e5078bc1fd3d808820c 100644
--- a/src/adw-tab-button.c
+++ b/src/adw-tab-button.c
@@ -112,6 +112,9 @@ update_label_scale (AdwTabButton *self,
 
   g_object_get (settings, "gtk-xft-dpi", &xft_dpi, NULL);
 
+  if (xft_dpi == 0)
+    xft_dpi = 96 * PANGO_SCALE;
+
   attrs = pango_attr_list_new ();
 
   scale_attribute = pango_attr_scale_new (XFT_DPI_MULTIPLIER / (double) xft_dpi);