diff --git a/Data/Octree.hs b/Data/Octree.hs
--- a/Data/Octree.hs
+++ b/Data/Octree.hs
@@ -6,6 +6,7 @@
                    insert,
                    nearest,
                    depth,
+                   size,
                    withinRange)
 where
 
diff --git a/Data/Octree/Internal.hs b/Data/Octree/Internal.hs
--- a/Data/Octree/Internal.hs
+++ b/Data/Octree/Internal.hs
@@ -6,7 +6,7 @@
                             octreeStep, octantDistance, splitBy', joinStep, splitStep, allOctants, octantDistance',
                             cmp,
                             pickClosest,
-                            depth
+                            depth, size
                             ) where
 
 import Data.Vector.V3
@@ -57,10 +57,6 @@
 -- | Enumerated type to indicate octants in 3D-space relative to given center.
 data ODir = SWD | SED | NWD | NED | SWU | SEU | NWU | NEU deriving (Eq, Ord, Enum, Show, Bounded)
 
-depth :: Octree a -> Int
-depth (Leaf l) = 0
-depth (Node _ a b c d e f g h) = Prelude.maximum . map (\n -> depth n + 1) $ [a, b, c, d, e, f, g, h]
-
 -- | Internal method that gives octant of a first vector relative to the second vector as a center.
 cmp :: Vector3 -> Vector3 -> ODir
 cmp ca cb = joinStep (cx, cy, cz)
@@ -297,4 +293,14 @@
                             octantDistances $ pt - split node   -- find octant distances
   where
     recurseOctant (octant, _d) = withinRange r pt . octreeStep node $ octant
+
+subnodes (Leaf _) = []
+subnodes node     = map (octreeStep node) allOctants
+
+depth :: Octree a -> Int
+depth (Leaf _) = 0
+depth node     = foldr max 0 . map (+1) . map depth . subnodes $ node
+
+size :: Octree a -> Int
+size =  length . toList
 
diff --git a/Octree.cabal b/Octree.cabal
--- a/Octree.cabal
+++ b/Octree.cabal
@@ -1,5 +1,5 @@
 name:                Octree
-version:             0.3
+version:             0.4
 stability:           beta
 homepage:            https://github.com/mgajda/octree
 package-url:         http://hackage.haskell.org/package/octree
diff --git a/tests/test_Octree.hs b/tests/test_Octree.hs
--- a/tests/test_Octree.hs
+++ b/tests/test_Octree.hs
@@ -103,4 +103,12 @@
 
 genericProperty_fmap f l = (sort . map (Control.Arrow.second f) $ l) == (sort . toList . fmap f . fromList $ l)
 
+prop_depth_empty = depth (Leaf []) == 0
+
+prop_depth_upper_bound l = depth ot <= max 0 (ceiling . logBase 2 . realToFrac $ size) -- worst splitting ratio possible when we take midpoint (and inputs are colinear)
+  where ot   = fromList l
+        size = length l
+
+prop_size l = size (fromList l) == length l
+
 main = $quickCheckAll