diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
index aa07b81687ff..6dafb8d6cfc2 100644
--- a/lib/matplotlib/backend_bases.py
+++ b/lib/matplotlib/backend_bases.py
@@ -2657,6 +2657,14 @@ def mouse_move(self, event):
                             if data_str is not None:
                                 s = s + ' ' + data_str
 
+                if self.mode == 'zoom rect' and self._xypress and not event.inaxes.have_units():
+                    lastx, lasty, a, ind, view = self._xypress[0]
+                    trans = event.inaxes.transData.inverted()
+                    last_xdata, last_ydata = trans.transform_point((lastx, lasty))
+                    dx = event.inaxes.format_xdata(event.xdata - last_xdata)
+                    dy = event.inaxes.format_ydata(event.ydata - last_ydata)
+                    s += ' (\N{GREEK CAPITAL LETTER DELTA}x={}\t\N{GREEK CAPITAL LETTER DELTA}y={})'.format(dx, dy)
+
                 if len(self.mode):
                     self.set_message('%s, %s' % (self.mode, s))
                 else: