diff --git a/IPython/core/magics/execution.py b/IPython/core/magics/execution.py
index f3688f4..12f62b2 100644
--- a/IPython/core/magics/execution.py
+++ b/IPython/core/magics/execution.py
@@ -1592,17 +1592,17 @@ def _format_time(timespan, precision=3):
                 break
         return " ".join(time)
 
-    
-    # Unfortunately the unicode 'micro' symbol can cause problems in
-    # certain terminals.  
+
+    # Unfortunately characters outside of range(128) can cause problems in
+    # certain terminals.
     # See bug: https://bugs.launchpad.net/ipython/+bug/348466
     # Try to prevent crashes by being more secure than it needs to
     # E.g. eclipse is able to print a µ, but has no sys.stdout.encoding set.
-    units = [u"s", u"ms",u'us',"ns"] # the save value   
+    units = [u"s", u"ms",u'us',"ns"] # the safe value
     if hasattr(sys.stdout, 'encoding') and sys.stdout.encoding:
         try:
-            u'\xb5'.encode(sys.stdout.encoding)
-            units = [u"s", u"ms",u'\xb5s',"ns"]
+            u'μ'.encode(sys.stdout.encoding)
+            units = [u"s", u"ms",u'μs',"ns"]
         except:
             pass
     scaling = [1, 1e3, 1e6, 1e9]
diff --git a/IPython/core/tests/test_magic.py b/IPython/core/tests/test_magic.py
index da998fa..c2cad41 100644
--- a/IPython/core/tests/test_magic.py
+++ b/IPython/core/tests/test_magic.py
@@ -529,6 +529,12 @@ def test_time_local_ns():
     assert ip.user_ns["myvar"] == 1
     del ip.user_ns["myvar"]
 
+def test_time_microseconds_display():
+    """Ensure ASCII is used when necessary"""
+    with mock.patch('sys.stdout', io.TextIOWrapper(StringIO(), encoding='utf-8')):
+        assert execution._format_time(0.000001) == '1 \u03bcs'
+    with mock.patch('sys.stdout', io.TextIOWrapper(StringIO(), encoding='ascii')):
+        assert execution._format_time(0.000001) == '1 us'
 
 # Test %%capture magic. Added to test issue #13926
 def test_capture():