diff --git a/opendm/tiles/gdal2tiles.py b/opendm/tiles/gdal2tiles.py
index 081c335a5..bd9225c66 100644
--- a/opendm/tiles/gdal2tiles.py
+++ b/opendm/tiles/gdal2tiles.py
@@ -209,7 +209,6 @@ def __init__(self, tileSize=256):
         self.initialResolution = 2 * math.pi * 6378137 / self.tileSize
         # 156543.03392804062 for tileSize 256 pixels
         self.originShift = 2 * math.pi * 6378137 / 2.0
-        # 20037508.342789244
 
     def LatLonToMeters(self, lat, lon):
         "Converts given lat/lon in WGS84 Datum to XY in Spherical Mercator EPSG:3857"
@@ -223,10 +222,11 @@ def LatLonToMeters(self, lat, lon):
     def MetersToLatLon(self, mx, my):
         "Converts XY point from Spherical Mercator EPSG:3857 to lat/lon in WGS84 Datum"
 
-        lon = (mx / self.originShift) * 180.0
-        lat = (my / self.originShift) * 180.0
-
-        lat = 180 / math.pi * (2 * math.atan(math.exp(lat * math.pi / 180.0)) - math.pi / 2.0)
+        inv_originShift = 180.0 / self.originShift
+        lon = mx * inv_originShift
+        lat = my * inv_originShift
+        pi = math.pi
+        lat = 180.0 / pi * (2.0 * math.atan(math.exp(lat * pi / 180.0)) - pi / 2.0)
         return lat, lon
 
     def PixelsToMeters(self, px, py, zoom):
@@ -356,15 +356,17 @@ class GlobalGeodetic(object):
 
     def __init__(self, tmscompatible, tileSize=256):
         self.tileSize = tileSize
+        # Precompute inverse, since division for each call may be expensive if tileSize changes.
+        inv_tileSize = 1.0 / self.tileSize
         if tmscompatible is not None:
             # Defaults the resolution factor to 0.703125 (2 tiles @ level 0)
             # Adhers to OSGeo TMS spec
             # http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification#global-geodetic
-            self.resFact = 180.0 / self.tileSize
+            self.resFact = 180.0 * inv_tileSize
         else:
             # Defaults the resolution factor to 1.40625 (1 tile @ level 0)
             # Adheres OpenLayers, MapProxy, etc default resolution for WMTS
-            self.resFact = 360.0 / self.tileSize
+            self.resFact = 360.0 * inv_tileSize
 
     def LonLatToPixels(self, lon, lat, zoom):
         "Converts lon/lat to pixel coordinates in given zoom of the EPSG:4326 pyramid"
@@ -403,17 +405,22 @@ def ZoomForPixelSize(self, pixelSize):
                     return 0    # We don't want to scale up
 
     def TileBounds(self, tx, ty, zoom):
-        "Returns bounds of the given tile"
-        res = self.resFact / 2**zoom
-        return (
-            tx*self.tileSize*res - 180,
-            ty*self.tileSize*res - 90,
-            (tx+1)*self.tileSize*res - 180,
-            (ty+1)*self.tileSize*res - 90
-        )
+        """Returns bounds of the given tile"""
+        # Use bitshift for integer powers of two for performance
+        # This avoids repeated computation of the same value
+        if isinstance(zoom, int) and 0 <= zoom <= 30:
+            res = self.resFact / (1 << zoom)
+        else:
+            res = self.resFact / 2**zoom
+        tile_factor = self.tileSize * res
+        tx0 = tx * tile_factor - 180
+        ty0 = ty * tile_factor - 90
+        tx1 = (tx + 1) * tile_factor - 180
+        ty1 = (ty + 1) * tile_factor - 90
+        return (tx0, ty0, tx1, ty1)
 
     def TileLatLonBounds(self, tx, ty, zoom):
-        "Returns bounds of the given tile in the SWNE form"
+        """Returns bounds of the given tile in the SWNE form"""
         b = self.TileBounds(tx, ty, zoom)
         return (b[1], b[0], b[3], b[2])