diff --git a/doc/MODULE_MIGRATION.md b/doc/MODULE_MIGRATION.md
index b04ea1a..8e8e9bf 100644
--- a/doc/MODULE_MIGRATION.md
+++ b/doc/MODULE_MIGRATION.md
@@ -7,3 +7,4 @@
 - engine.input.register_callback is now core.input.register
 - update() only has a single parameter (self) (no widgets anymore)
 - bumblebee.util.format stuff moved into util.format (byte, aslist, asbool, etc.)
+- util.format.duration -> shorten -> compact, suffix -> unit
diff --git a/modules/core/battery.py b/modules/core/battery.py
index ffe39fe..68fcf5c 100644
--- a/modules/core/battery.py
+++ b/modules/core/battery.py
@@ -61,7 +61,7 @@ class Module(core.module.Module):
                 return ''
         except Exception:
             return ''
-        return util.format.duration(estimate*60, shorten=True, suffix=True) # estimate is in minutes
+        return util.format.duration(estimate*60, compact=True, unit=True) # estimate is in minutes
 
     def capacity(self, widget):
         widget.set('capacity', -1)
diff --git a/tests/util/test_format.py b/tests/util/test_format.py
index 95773b2..885bcb3 100644
--- a/tests/util/test_format.py
+++ b/tests/util/test_format.py
@@ -63,4 +63,17 @@ class format(unittest.TestCase):
         self.assertEqual('4.50GiB', byte(1024*1024*1024*4 + 1024*1024*512))
         self.assertEqual('2048.00GiB', byte(1024*1024*1024*1024*2))
 
+    def test_duration(self):
+        self.assertEqual('04:20:00', duration(4*60*60+20*60))
+        self.assertEqual('04:20:00h', duration(4*60*60+20*60, unit=True))
+        self.assertEqual('04:20h', duration(4*60*60+20*60, compact=True, unit=True))
+
+        self.assertEqual('20:00', duration(20*60))
+        self.assertEqual('20:00m', duration(20*60, unit=True))
+        self.assertEqual('20:00m', duration(20*60, compact=True, unit=True))
+
+        self.assertEqual('00:20', duration(20))
+        self.assertEqual('00:20m', duration(20, unit=True))
+        self.assertEqual('00:20m', duration(20, compact=True, unit=True))
+
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4
diff --git a/util/format.py b/util/format.py
index 141ef32..5ed29f6 100644
--- a/util/format.py
+++ b/util/format.py
@@ -30,19 +30,19 @@ def byte(val, fmt='{:.2f}'):
         val /= 1024.0
     return '{}GiB'.format(fmt).format(val*1024.0)
 
-def duration(duration, shorten=False, suffix=False):
+def duration(duration, compact=False, unit=False):
     duration = int(duration)
     minutes, seconds = divmod(duration, 60)
     hours, minutes = divmod(minutes, 60)
     suf = 'm'
     res = '{:02d}:{:02d}'.format(minutes, seconds)
     if hours > 0:
-        if shorten:
+        if compact:
             res = '{:02d}:{:02d}'.format(hours, minutes)
         else:
             res = '{:02d}:{}'.format(hours, res)
         suf = 'h'
 
-    return '{}{}'.format(res, suf if suffix else '')
+    return '{}{}'.format(res, suf if unit else '')
 
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4