diff --git a/hublib/ui/numvalue.py b/hublib/ui/numvalue.py
index 0867d48..ee875bf 100644
--- a/hublib/ui/numvalue.py
+++ b/hublib/ui/numvalue.py
@@ -173,7 +173,8 @@ def cb(self, _):
                     self.dd.value = self.default
                 return
 
-            val = '{:~}'.format(val)
+            if self.units is not None:
+                val = '{:~}'.format(val)
             if val != self.oldval:
                 self.no_cb = True
                 self.dd.value = val
diff --git a/tests/test_number.py b/tests/test_number.py
index 815d030..28b4377 100644
--- a/tests/test_number.py
+++ b/tests/test_number.py
@@ -82,10 +82,19 @@ def test_val_unitless(self):
         assert x.value == 5
         assert x.str == '5'
 
+        # simulate pressing enter
+        x.cb('')
+        assert x.value == 5
+        assert x.str == '5'
+
         x.value = 4.4
         assert x.value == 4.4
         assert x.str == '4.4'
 
+        x.cb('')
+        assert x.value == 4.4
+        assert x.str == '4.4'
+
         # try some bad values
         with pytest.raises(ValueError):
             x.value = '4 m'