diff --git a/conky_dashboard.lua b/conky_dashboard.lua
index 05eb0a6..90a0093 100644
--- a/conky_dashboard.lua
+++ b/conky_dashboard.lua
@@ -519,7 +519,7 @@ function conky_clock_rings()
         str=conky_parse(str)
         
         value=tonumber(str)
-        pct=value/pt['max']
+        pct=(value or 0)/pt['max']
         
         draw_ring(cr,pct,pt)
     end