diff --git a/i3pystatus/core/util.py b/i3pystatus/core/util.py
index d705b8d..614fd6d 100644
--- a/i3pystatus/core/util.py
+++ b/i3pystatus/core/util.py
@@ -365,18 +365,23 @@ def internet():
         return False
 
 
-def make_graph(values, upper_limit=100.0, style="blocks"):
+def make_graph(values, lower_limit=0.0, upper_limit=100.0, style="blocks"):
     """
     Draws a graph made of unicode characters.
 
     :param values: An array of values to graph.
-    :param upper_limit: Maximum value for the y axis.
+    :param lower_limit: Minimum value for the y axis (or None for dynamic).
+    :param upper_limit: Maximum value for the y axis (or None for dynamic).
     :param style: Drawing style ('blocks', 'braille-fill', 'braille-peak', or 'braille-snake').
     :returns: Bar as a string
     """
+
     values = [float(n) for n in values]
-    mn, mx = min(values), max(max(values), float(upper_limit))
+    mn, mx = min(values), max(values)
+    mn = mn if lower_limit == None else min(mn, float(lower_limit))
+    mx = mx if upper_limit == None else max(mx, float(upper_limit))
     extent = mx - mn
+
     if style == 'blocks':
         bar = u'_▁▂▃▄▅▆▇█'
         bar_count = len(bar) - 1
diff --git a/i3pystatus/cpu_usage_graph.py b/i3pystatus/cpu_usage_graph.py
index e648db1..4776348 100644
--- a/i3pystatus/cpu_usage_graph.py
+++ b/i3pystatus/cpu_usage_graph.py
@@ -46,7 +46,7 @@ class CpuUsageGraph(CpuUsage, ColorRangeModule):
         self.cpu_readings.insert(0, core_reading)
         self.cpu_readings = self.cpu_readings[:self.graph_width]
 
-        graph = make_graph(self.cpu_readings, 100.0, self.graph_style)
+        graph = make_graph(self.cpu_readings, 0.0, 100.0, self.graph_style)
         format_options.update({'cpu_graph': graph})
 
         color = self.get_gradient(core_reading, self.colors)
diff --git a/i3pystatus/network.py b/i3pystatus/network.py
index 303838d..afb9ddb 100644
--- a/i3pystatus/network.py
+++ b/i3pystatus/network.py
@@ -331,7 +331,7 @@ class Network(IntervalModule, ColorRangeModule):
         # Cycle array by inserting at the start and chopping off the last element
         self.kbs_arr.insert(0, kbs)
         self.kbs_arr = self.kbs_arr[:self.graph_width]
-        return make_graph(self.kbs_arr, self.upper_limit, self.graph_style)
+        return make_graph(self.kbs_arr, 0.0, self.upper_limit, self.graph_style)
 
     def run(self):
         format_values = dict(kbs="", network_graph="", bytes_sent="", bytes_recv="", packets_sent="", packets_recv="",