diff --git a/lib/matplotlib/artist.py b/lib/matplotlib/artist.py
index bf096888ea66..6971a67215bf 100644
--- a/lib/matplotlib/artist.py
+++ b/lib/matplotlib/artist.py
@@ -232,6 +232,9 @@ def stale(self, val):
     def get_window_extent(self, renderer):
         """
         Get the axes bounding box in display space.
+
+        The bounding box' width and height are nonnegative.
+
         Subclasses should override for inclusion in the bounding box
         "tight" calculation. Default is to return an empty bounding
         box at 0, 0.
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
index 9515e03e5d75..e15e061d5ff4 100644
--- a/lib/matplotlib/axes/_base.py
+++ b/lib/matplotlib/axes/_base.py
@@ -4334,9 +4334,9 @@ def get_tightbbox(self, renderer, call_axes_locator=True,
 
         for a in bbox_artists:
             bbox = a.get_tightbbox(renderer)
-            if (bbox is not None and
-                    (bbox.width != 0 or bbox.height != 0) and
-                    np.isfinite(bbox.width) and np.isfinite(bbox.height)):
+            if (bbox is not None
+                    and 0 < bbox.width < np.inf
+                    and 0 < bbox.height < np.inf):
                 bb.append(bbox)
 
         _bbox = mtransforms.Bbox.union(
diff --git a/lib/matplotlib/axis.py b/lib/matplotlib/axis.py
index e751176c8267..90f0dce3a405 100644
--- a/lib/matplotlib/axis.py
+++ b/lib/matplotlib/axis.py
@@ -1151,21 +1151,17 @@ def get_tightbbox(self, renderer):
         self._update_offset_text_position(ticklabelBoxes, ticklabelBoxes2)
         self.offsetText.set_text(self.major.formatter.get_offset())
 
-        bb = []
-
-        for a in [self.label, self.offsetText]:
-            bbox = a.get_window_extent(renderer)
-            if (np.isfinite(bbox.width) and np.isfinite(bbox.height) and
-                    a.get_visible()):
-                bb.append(bbox)
-        bb.extend(ticklabelBoxes)
-        bb.extend(ticklabelBoxes2)
-        bb = [b for b in bb if ((b.width != 0 or b.height != 0) and
-                                np.isfinite(b.width) and
-                                np.isfinite(b.height))]
-        if bb:
-            _bbox = mtransforms.Bbox.union(bb)
-            return _bbox
+        bboxes = [
+            *(a.get_window_extent(renderer)
+              for a in [self.label, self.offsetText]
+              if a.get_visible()),
+            *ticklabelBoxes,
+            *ticklabelBoxes2,
+        ]
+        bboxes = [b for b in bboxes
+                  if 0 < b.width < np.inf and 0 < b.height < np.inf]
+        if bboxes:
+            return mtransforms.Bbox.union(bboxes)
         else:
             return None