diff --git a/pym/_emerge/resolver/output.py b/pym/_emerge/resolver/output.py
index 5f550be..aefc3f4 100644
--- a/pym/_emerge/resolver/output.py
+++ b/pym/_emerge/resolver/output.py
@@ -18,6 +18,7 @@
 from portage.dep import cpvequal, _repo_separator, _slot_separator
 from portage.eapi import _get_eapi_attrs
 from portage.exception import InvalidDependString, SignatureException
+from portage.localization import localized_size
 from portage.package.ebuild.config import _get_feature_flags
 from portage.package.ebuild._spawn_nofetch import spawn_nofetch
 from portage.output import ( blue, colorize, create_color_func,
@@ -30,7 +31,7 @@
 from _emerge.Blocker import Blocker
 from _emerge.create_world_atom import create_world_atom
 from _emerge.resolver.output_helpers import ( _DisplayConfig, _tree_display,
-	_PackageCounters, _create_use_string, _format_size, _calc_changelog, PkgInfo)
+	_PackageCounters, _create_use_string, _calc_changelog, PkgInfo)
 from _emerge.show_invalid_depstring_notice import show_invalid_depstring_notice
 
 if sys.hexversion >= 0x3000000:
@@ -330,7 +331,7 @@
 						self.myfetchlist.add(myfetchfile)
 				if pkg_info.ordered:
 					self.counters.totalsize += mysize
-			self.verboseadd += _format_size(mysize)
+			self.verboseadd += localized_size(mysize)
 
 		if self.quiet_repo_display:
 			# overlay verbose
diff --git a/pym/_emerge/resolver/output_helpers.py b/pym/_emerge/resolver/output_helpers.py
index 58b2694..e0ee3e0 100644
--- a/pym/_emerge/resolver/output_helpers.py
+++ b/pym/_emerge/resolver/output_helpers.py
@@ -1,4 +1,4 @@
-# Copyright 2010-2013 Gentoo Foundation
+# Copyright 2010-2014 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 """Contains private support functions for the Display class
@@ -17,6 +17,7 @@
 from portage import os
 from portage import _encodings, _unicode_encode
 from portage._sets.base import InternalPackageSet
+from portage.localization import localized_size
 from portage.output import (blue, bold, colorize, create_color_func,
 	green, red, teal, turquoise, yellow)
 bad = create_color_func("BAD")
@@ -158,7 +159,7 @@
 		myoutput.append(", ".join(details))
 		if total_installs != 0:
 			myoutput.append(")")
-		myoutput.append(", Size of downloads: %s" % _format_size(self.totalsize))
+		myoutput.append(", Size of downloads: %s" % localized_size(self.totalsize))
 		if self.restrict_fetch:
 			myoutput.append("\nFetch Restriction: %s package" % \
 				self.restrict_fetch)
@@ -234,21 +235,6 @@
 		self.pkg = depgraph._pkg
 
 
-# formats a size given in bytes nicely
-def _format_size(mysize):
-	if isinstance(mysize, basestring):
-		return mysize
-	if 0 != mysize % 1024:
-		# Always round up to the next kB so that it doesn't show 0 kB when
-		# some small file still needs to be fetched.
-		mysize += 1024 - mysize % 1024
-	mystr=str(mysize//1024)
-	mycount=len(mystr)
-	while (mycount > 3):
-		mycount-=3
-		mystr=mystr[:mycount]+","+mystr[mycount:]
-	return mystr+" kB"
-
 def _create_use_string(conf, name, cur_iuse, iuse_forced, cur_use,
 	old_iuse, old_use,
 	is_new, feature_flags, reinst_flags):
diff --git a/pym/_emerge/search.py b/pym/_emerge/search.py
index bd74fb7..4b0fd9f 100644
--- a/pym/_emerge/search.py
+++ b/pym/_emerge/search.py
@@ -1,4 +1,4 @@
-# Copyright 1999-2013 Gentoo Foundation
+# Copyright 1999-2014 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 from __future__ import print_function
@@ -7,6 +7,7 @@
 import portage
 from portage import os
 from portage.dbapi.porttree import _parse_uri_map
+from portage.localization import localized_size
 from portage.output import  bold, bold as white, darkgreen, green, red
 from portage.util import writemsg_stdout
 
@@ -348,12 +349,7 @@
 							break
 
 					if myebuild and file_size_str is None:
-						mystr = str(mysum[0] // 1024)
-						mycount = len(mystr)
-						while (mycount > 3):
-							mycount -= 3
-							mystr = mystr[:mycount] + "," + mystr[mycount:]
-						file_size_str = mystr + " kB"
+						file_size_str = localized_size(mysum[0])
 
 					if self.verbose:
 						if available:
diff --git a/pym/portage/localization.py b/pym/portage/localization.py
index b54835a..e4d87b6 100644
--- a/pym/portage/localization.py
+++ b/pym/portage/localization.py
@@ -2,6 +2,9 @@
 # Copyright 2004-2014 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
+import locale
+import math
+
 from portage import _unicode_decode
 
 # We define this to make the transition easier for us.
@@ -25,3 +28,12 @@
 	print(_("A: %(a)s -- B: %(b)s -- C: %(c)s") %
 	      {"a": a_value, "b": b_value, "c": c_value})
 
+def localized_size(num_bytes):
+	"""
+	Return pretty localized size string for num_bytes size
+	(given in bytes). The output will be in kibibytes.
+	"""
+
+	# always round up, so that small files don't end up as '0 KiB'
+	num_kib = math.ceil(num_bytes / 1024)
+	return locale.format('%d', num_kib, grouping=True) + ' KiB'