diff --git a/mercurial/ui.py b/mercurial/ui.py
--- a/mercurial/ui.py
+++ b/mercurial/ui.py
@@ -380,7 +380,7 @@ class ui(object):
 
         if total:
             pct = 100.0 * pos / total
-            self.debug('%s:%s %s/%s%s (%4.2g%%)\n'
+            self.debug('%s:%s %s/%s%s (%4.2f%%)\n'
                      % (topic, item, pos, total, unit, pct))
         else:
             self.debug('%s:%s %s%s\n' % (topic, item, pos, unit))
diff --git a/tests/test-relink.out b/tests/test-relink.out
--- a/tests/test-relink.out
+++ b/tests/test-relink.out
@@ -17,7 +17,7 @@ not linkable: 00changelog.i
 not linkable: 00manifest.i
 not linkable: data/b.i
 pruned down to 2 probably relinkable files
-relink: data/a.i 1/2  files (  50%)
+relink: data/a.i 1/2  files (50.00%)
 not linkable: data/dummy.i
 relinked 1 files (136 bytes reclaimed)
 % check hardlinks