diff --git a/configure.ac b/configure.ac
index 72e7bfb2..2b840ee9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -255,6 +255,7 @@ mu/Makefile
 mu/tests/Makefile
 lib/Makefile
 lib/doxyfile
+lib/utils/Makefile
 lib/parser/Makefile
 lib/tests/Makefile
 mu4e/Makefile
diff --git a/lib/Makefile.am b/lib/Makefile.am
index d36d9093..d80fbd88 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -18,7 +18,7 @@ include $(top_srcdir)/gtest.mk
 
 # enforce compiling guile (optionally) first,then this dir first
 # before decending into tests/
-SUBDIRS= parser . tests
+SUBDIRS= utils parser . tests
 
 if HAVE_JSON_GLIB
 json_srcs=					\
@@ -66,14 +66,10 @@ libmu_la_SOURCES=				\
 	mu-contacts.hh				\
 	mu-container.c				\
 	mu-container.h				\
-	mu-date.c				\
-	mu-date.h				\
 	mu-flags.h				\
 	mu-flags.c				\
 	mu-index.c				\
 	mu-index.h				\
-	mu-log.c				\
-	mu-log.h				\
 	mu-maildir.c				\
 	mu-maildir.h				\
 	mu-msg-crypto.c				\
@@ -103,12 +99,8 @@ libmu_la_SOURCES=				\
 	mu-script.h				\
 	mu-store.cc				\
 	mu-store.hh				\
-	mu-str.c				\
-	mu-str.h				\
 	mu-threader.c				\
-	mu-threader.h				\
-	mu-util.c				\
-	mu-util.h
+	mu-threader.h
 
 libmu_la_LIBADD=				\
 	$(XAPIAN_LIBS)				\
@@ -116,6 +108,7 @@ libmu_la_LIBADD=				\
 	$(GLIB_LIBS)				\
 	$(GUILE_LIBS)				\
 	$(JSON_GLIB_LIBS)			\
+	${builddir}/utils/libmu-utils.la	\
 	${builddir}/parser/libmuxparser.la
 
 libmu_la_LDFLAGS=				\
diff --git a/lib/utils/Makefile.am b/lib/utils/Makefile.am
new file mode 100644
index 00000000..20f6727d
--- /dev/null
+++ b/lib/utils/Makefile.am
@@ -0,0 +1,69 @@
+## Copyright (C) 2019 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software Foundation,
+## Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+include $(top_srcdir)/gtest.mk
+
+AM_CFLAGS=								\
+	$(WARN_CFLAGS)							\
+	$(GLIB_CFLAGS)							\
+	$(ASAN_CFLAGS)							\
+	-DMU_TESTMAILDIR=\"${abs_top_srcdir}/lib/tests/testdir\"	\
+	-DMU_TESTMAILDIR2=\"${abs_top_srcdir}/lib/tests/testdir2\"	\
+	-Wno-format-nonliteral						\
+	-Wno-switch-enum						\
+	-Wno-deprecated-declarations					\
+	-Wno-inline
+
+AM_CXXFLAGS=								\
+	$(WARN_CXXFLAGS)						\
+	$(GLIB_CFLAGS)							\
+	$(ASAN_CXXFLAGS)
+
+noinst_LTLIBRARIES=							\
+	libmu-utils.la
+
+libmu_utils_la_SOURCES=							\
+	mu-date.c							\
+	mu-date.h							\
+	mu-log.c							\
+	mu-log.h							\
+	mu-str.c							\
+	mu-str.h							\
+	mu-util.c							\
+	mu-util.h
+
+libmu_utils_la_LIBADD=							\
+	$(GLIB_LIBS)
+
+libmu_utils_la_LDFLAGS=							\
+	$(ASAN_LDFLAGS)
+
+noinst_PROGRAMS=							\
+	$(TEST_PROGS)
+
+TEST_PROGS+=								\
+	test-mu-util
+test_mu_util_SOURCES=							\
+	test-mu-util.c
+test_mu_util_LDADD=							\
+	libmu-utils.la
+
+TEST_PROGS+=								\
+	test-mu-str
+test_mu_str_SOURCES=							\
+	test-mu-str.c
+test_mu_str_LDADD=							\
+	libmu-utils.la
diff --git a/lib/mu-date.c b/lib/utils/mu-date.c
similarity index 100%
rename from lib/mu-date.c
rename to lib/utils/mu-date.c
diff --git a/lib/mu-date.h b/lib/utils/mu-date.h
similarity index 100%
rename from lib/mu-date.h
rename to lib/utils/mu-date.h
diff --git a/lib/mu-log.c b/lib/utils/mu-log.c
similarity index 100%
rename from lib/mu-log.c
rename to lib/utils/mu-log.c
diff --git a/lib/mu-log.h b/lib/utils/mu-log.h
similarity index 100%
rename from lib/mu-log.h
rename to lib/utils/mu-log.h
diff --git a/lib/mu-str.c b/lib/utils/mu-str.c
similarity index 98%
rename from lib/mu-str.c
rename to lib/utils/mu-str.c
index fdb58178..9d338771 100644
--- a/lib/mu-str.c
+++ b/lib/utils/mu-str.c
@@ -37,25 +37,14 @@
 const char*
 mu_str_size_s  (size_t s)
 {
-	static char buf[32];
-
-#ifdef HAVE_GLIB216
-	char *tmp;
+	static char	 buf[32];
+	char		*tmp;
 
 	tmp = g_format_size_for_display ((goffset)s);
 	strncpy (buf, tmp, sizeof(buf));
 	buf[sizeof(buf) -1] = '\0'; /* just in case */
 	g_free (tmp);
 
-#else
-	if (s >= 1000 * 1000)
-		g_snprintf(buf, sizeof(buf), "%.1f MB",
-			   (double)s/(1000*1000));
-	else
-		g_snprintf(buf, sizeof(buf), "%.1f kB", (double)s/(1000));
-#endif /*HAVE_GLIB216*/
-
-
 	return buf;
 }
 
diff --git a/lib/mu-str.h b/lib/utils/mu-str.h
similarity index 100%
rename from lib/mu-str.h
rename to lib/utils/mu-str.h
diff --git a/lib/mu-util.c b/lib/utils/mu-util.c
similarity index 100%
rename from lib/mu-util.c
rename to lib/utils/mu-util.c
diff --git a/lib/mu-util.h b/lib/utils/mu-util.h
similarity index 100%
rename from lib/mu-util.h
rename to lib/utils/mu-util.h
diff --git a/lib/tests/test-mu-str.c b/lib/utils/test-mu-str.c
similarity index 90%
rename from lib/tests/test-mu-str.c
rename to lib/utils/test-mu-str.c
index cf3906c4..ecba8fbf 100644
--- a/lib/tests/test-mu-str.c
+++ b/lib/utils/test-mu-str.c
@@ -45,15 +45,13 @@ test_mu_str_size_01 (void)
 
 	lc = localeconv();
 
-	tmp2 = g_strdup_printf ("0%s0 kB", lc->decimal_point);
-	g_assert_cmpstr (mu_str_size_s (0),           ==,  tmp2);
+	g_assert_cmpstr (mu_str_size_s (0), ==, "0 bytes");
+
+	tmp2 = g_strdup_printf ("97%s7 KB", lc->decimal_point);
+	g_assert_cmpstr (mu_str_size_s (100000), ==, tmp2);
 	g_free (tmp2);
 
-	tmp2 = g_strdup_printf ("100%s0 kB", lc->decimal_point);
-	g_assert_cmpstr (mu_str_size_s (100000),      ==,  tmp2);
-	g_free (tmp2);
-
-	tmp2 = g_strdup_printf ("1%s1 MB", lc->decimal_point);
+	tmp2 = g_strdup_printf ("1%s0 MB", lc->decimal_point);
 	g_assert_cmpstr (mu_str_size_s (1100*1000), ==,  tmp2);
 	g_free (tmp2);
 }
@@ -271,28 +269,6 @@ test_mu_str_to_list_strip (void)
 }
 
 
-static void
-test_mu_str_subject_normalize (void)
-{
-	int i;
-
-	struct {
-		const char *src, *exp;
-	} tests[] = {
-		{ "test123", "test123" },
-		{ "Re:test123", "test123" },
-		{ "Re: Fwd: test123", "test123" },
-		{ "Re[3]: Fwd: test123", "test123" },
-		{ "operation: mindcrime", "operation: mindcrime" }, /*...*/
-		{ "", "" }
-	};
-
-	for (i = 0; i != G_N_ELEMENTS(tests); ++i)
-		g_assert_cmpstr (mu_str_subject_normalize (tests[i].src), ==,
-				 tests[i].exp);
-}
-
-
 static void
 test_mu_str_replace (void)
 {
@@ -383,9 +359,6 @@ main (int argc, char *argv[])
 	g_test_add_func ("/mu-str/mu-str-esc-to-list",
 			 test_mu_str_esc_to_list);
 
-	g_test_add_func ("/mu-str/mu_str_subject_normalize",
-			 test_mu_str_subject_normalize);
-
 	g_test_add_func ("/mu-str/mu_str_remove_ctrl_in_place",
 			 test_mu_str_remove_ctrl_in_place);
 
diff --git a/lib/tests/test-mu-util.c b/lib/utils/test-mu-util.c
similarity index 100%
rename from lib/tests/test-mu-util.c
rename to lib/utils/test-mu-util.c
diff --git a/mu/tests/test-mu-cmd.c b/mu/tests/test-mu-cmd.c
index 870236d0..3163c2a6 100644
--- a/mu/tests/test-mu-cmd.c
+++ b/mu/tests/test-mu-cmd.c
@@ -348,9 +348,9 @@ test_mu_extract_01 (void)
 	g_assert_cmpstr (output,
 			 ==,
 			 "MIME-parts in this message:\n"
-			 "  1 <none> text/plain [<none>] (0.0 kB)\n"
-			 "  2 sittingbull.jpg image/jpeg [inline] (23.9 kB)\n"
-			 "  3 custer.jpg image/jpeg [inline] (21.6 kB)\n");
+			 "  1 <none> text/plain [<none>] (27 bytes)\n"
+			 "  2 sittingbull.jpg image/jpeg [inline] (23.3 KB)\n"
+			 "  3 custer.jpg image/jpeg [inline] (21.1 KB)\n");
 
 	/* we expect zero lines of error output */
 	g_assert_cmpuint (newlines_in_output(erroutput),==,0);