diff --git a/src/mplfinance/_panels.py b/src/mplfinance/_panels.py
index cf4d8956..7d8524a2 100644
--- a/src/mplfinance/_panels.py
+++ b/src/mplfinance/_panels.py
@@ -22,16 +22,16 @@ def _build_panels( figure, config ):
     ------
     The following items are used from `config`:
 
-    num_panels   : integer (0-9) or None
+    num_panels   : integer (0-31) or None
         number of panels to create
 
     addplot      : dict or None
         value for the `addplot=` kwarg passed into `mplfinance.plot()`
 
-    volume_panel : integer (0-9) or None
+    volume_panel : integer (0-31) or None
         panel id (0-number_of_panels)
 
-    main_panel   : integer (0-9) or None
+    main_panel   : integer (0-31) or None
         panel id (0-number_of_panels)
 
     panel_ratios : sequence or None
@@ -68,7 +68,7 @@ def _build_panels( figure, config ):
     panel_ratios = config['panel_ratios']
 
     if not _valid_panel_id(main_panel):
-        raise ValueError('main_panel id must be integer 0 to 9, but is '+str(main_panel))
+        raise ValueError('main_panel id must be integer 0 to 31, but is '+str(main_panel))
 
     if num_panels is None:  # then infer the number of panels:
         pset = {0} # start with a set including only panel zero
@@ -85,12 +85,12 @@ def _build_panels( figure, config ):
                 if panel in backwards_panel_compatibility:
                     panel = backwards_panel_compatibility[panel]
                 if not _valid_panel_id(panel):
-                    raise ValueError('addplot panel must be integer 0 to 9, but is "'+str(panel)+'"')
+                    raise ValueError('addplot panel must be integer 0 to 31, but is "'+str(panel)+'"')
                 pset.add(panel)
 
         if volume is True:
             if not _valid_panel_id(volume_panel):
-                raise ValueError('volume_panel must be integer 0 to 9, but is "'+str(volume_panel)+'"')
+                raise ValueError('volume_panel must be integer 0 to 31, but is "'+str(volume_panel)+'"')
             pset.add(volume_panel)
 
         pset.add(main_panel)