diff --git a/large_image/tilesource/base.py b/large_image/tilesource/base.py
index e4529d276..77a746eb5 100644
--- a/large_image/tilesource/base.py
+++ b/large_image/tilesource/base.py
@@ -1548,6 +1548,22 @@ def getInternalMetadata(self, **kwargs):
         """
         return None
 
+    def _xyzInRange(self, x, y, z):
+        """
+        Check if a tile at x, y, z is in range based on self.levels,
+        self.tileWidth, self.tileHeight, self.sizeX, and self.sizeY,  Raise an
+        exception if not.
+        """
+        if z < 0 or z >= self.levels:
+            raise exceptions.TileSourceException('z layer does not exist')
+        scale = 2 ** (self.levels - 1 - z)
+        offsetx = x * self.tileWidth * scale
+        if not (0 <= offsetx < self.sizeX):
+            raise exceptions.TileSourceException('x is outside layer')
+        offsety = y * self.tileHeight * scale
+        if not (0 <= offsety < self.sizeY):
+            raise exceptions.TileSourceException('y is outside layer')
+
     @methodcache()
     def getTile(self, x, y, z, pilImageAllowed=False, numpyAllowed=False,
                 sparseFallback=False, frame=None):
diff --git a/sources/gdal/large_image_source_gdal/__init__.py b/sources/gdal/large_image_source_gdal/__init__.py
index 1112db8b7..5f1342498 100644
--- a/sources/gdal/large_image_source_gdal/__init__.py
+++ b/sources/gdal/large_image_source_gdal/__init__.py
@@ -645,17 +645,12 @@ def _bandNumber(self, band, exc=True):
     @methodcache()
     def getTile(self, x, y, z, pilImageAllowed=False, numpyAllowed=False, **kwargs):
         if not self.projection:
-            if z < 0 or z >= self.levels:
-                raise TileSourceException('z layer does not exist')
+            self._xyzInRange(x, y, z)
             factor = int(2 ** (self.levels - 1 - z))
             x0 = int(x * factor * self.tileWidth)
             y0 = int(y * factor * self.tileHeight)
             x1 = int(min(x0 + factor * self.tileWidth, self.sourceSizeX))
             y1 = int(min(y0 + factor * self.tileHeight, self.sourceSizeY))
-            if x < 0 or x0 >= self.sizeX:
-                raise TileSourceException('x is outside layer')
-            if y < 0 or y0 >= self.sizeY:
-                raise TileSourceException('y is outside layer')
             w = int(max(1, round((x1 - x0) / factor)))
             h = int(max(1, round((y1 - y0) / factor)))
             with self._getDatasetLock:
diff --git a/sources/nd2/large_image_source_nd2/__init__.py b/sources/nd2/large_image_source_nd2/__init__.py
index 1aa81d7f9..5f0146fd1 100644
--- a/sources/nd2/large_image_source_nd2/__init__.py
+++ b/sources/nd2/large_image_source_nd2/__init__.py
@@ -307,17 +307,12 @@ def getInternalMetadata(self, **kwargs):
 
     @methodcache()
     def getTile(self, x, y, z, pilImageAllowed=False, numpyAllowed=False, **kwargs):
-        if z < 0 or z >= self.levels:
-            raise TileSourceException('z layer does not exist')
+        self._xyzInRange(x, y, z)
         step = int(2 ** (self.levels - 1 - z))
         x0 = x * step * self.tileWidth
         x1 = min((x + 1) * step * self.tileWidth, self.sizeX)
         y0 = y * step * self.tileHeight
         y1 = min((y + 1) * step * self.tileHeight, self.sizeY)
-        if x < 0 or x0 >= self.sizeX:
-            raise TileSourceException('x is outside layer')
-        if y < 0 or y0 >= self.sizeY:
-            raise TileSourceException('y is outside layer')
         frame = kwargs.get('frame')
         frame = int(frame) if frame else 0
         if frame < 0 or frame >= len(self._nd2):
diff --git a/sources/openjpeg/large_image_source_openjpeg/__init__.py b/sources/openjpeg/large_image_source_openjpeg/__init__.py
index b4b3eeb9c..0f7c54894 100644
--- a/sources/openjpeg/large_image_source_openjpeg/__init__.py
+++ b/sources/openjpeg/large_image_source_openjpeg/__init__.py
@@ -228,17 +228,12 @@ def getInternalMetadata(self, **kwargs):
 
     @methodcache()
     def getTile(self, x, y, z, pilImageAllowed=False, numpyAllowed=False, **kwargs):
-        if z < 0 or z >= self.levels:
-            raise TileSourceException('z layer does not exist')
+        self._xyzInRange(x, y, z)
         step = int(2 ** (self.levels - 1 - z))
         x0 = x * step * self.tileWidth
         x1 = min((x + 1) * step * self.tileWidth, self.sizeX)
         y0 = y * step * self.tileHeight
         y1 = min((y + 1) * step * self.tileHeight, self.sizeY)
-        if x < 0 or x0 >= self.sizeX:
-            raise TileSourceException('x is outside layer')
-        if y < 0 or y0 >= self.sizeY:
-            raise TileSourceException('y is outside layer')
         scale = None
         if z < self._minlevel:
             scale = int(2 ** (self._minlevel - z))
diff --git a/sources/openslide/large_image_source_openslide/__init__.py b/sources/openslide/large_image_source_openslide/__init__.py
index 7d82c9767..e61f37367 100644
--- a/sources/openslide/large_image_source_openslide/__init__.py
+++ b/sources/openslide/large_image_source_openslide/__init__.py
@@ -259,8 +259,7 @@ def getInternalMetadata(self, **kwargs):
 
     @methodcache()
     def getTile(self, x, y, z, pilImageAllowed=False, numpyAllowed=False, **kwargs):
-        if z < 0:
-            raise TileSourceException('z layer does not exist')
+        self._xyzInRange(x, y, z)
         try:
             svslevel = self._svslevels[z]
         except IndexError:
@@ -271,11 +270,7 @@ def getTile(self, x, y, z, pilImageAllowed=False, numpyAllowed=False, **kwargs):
         # scaled by the tile size and by the z level.
         scale = 2 ** (self.levels - 1 - z)
         offsetx = x * self.tileWidth * scale
-        if not (0 <= offsetx < self.sizeX):
-            raise TileSourceException('x is outside layer')
         offsety = y * self.tileHeight * scale
-        if not (0 <= offsety < self.sizeY):
-            raise TileSourceException('y is outside layer')
         # We ask to read an area that will cover the tile at the z level.  The
         # scale we computed in the __init__ process for this svs level tells
         # how much larger a region we need to read.
diff --git a/sources/tiff/large_image_source_tiff/__init__.py b/sources/tiff/large_image_source_tiff/__init__.py
index d9bf16bc6..a61c37cd9 100644
--- a/sources/tiff/large_image_source_tiff/__init__.py
+++ b/sources/tiff/large_image_source_tiff/__init__.py
@@ -275,15 +275,7 @@ def getInternalMetadata(self, **kwargs):
     @methodcache()
     def getTile(self, x, y, z, pilImageAllowed=False, numpyAllowed=False,
                 sparseFallback=False, **kwargs):
-        if z < 0:
-            raise TileSourceException('z layer does not exist')
-        scale = 2 ** (self.levels - 1 - z)
-        offsetx = x * self.tileWidth * scale
-        if not (0 <= offsetx < self.sizeX):
-            raise TileSourceException('x is outside layer')
-        offsety = y * self.tileHeight * scale
-        if not (0 <= offsety < self.sizeY):
-            raise TileSourceException('y is outside layer')
+        self._xyzInRange(x, y, z)
         try:
             allowStyle = True
             if self._tiffDirectories[z] is None: