diff --git a/progressbar/utils.py b/progressbar/utils.py
index 1df42635..0f8f0de1 100644
--- a/progressbar/utils.py
+++ b/progressbar/utils.py
@@ -36,7 +36,7 @@ def scale_1024(x, n_prefixes):
     >>> scale_1024(2048, 3)
     (2.0, 1)
     '''
-    if x == 0:
+    if x <= 0:
         power = 0
     else:
         power = min(int(math.log(x, 2) / 10), n_prefixes - 1)