diff --git a/src/coordinates.F90 b/src/coordinates.F90
index c0c9da9..0d652de 100644
--- a/src/coordinates.F90
+++ b/src/coordinates.F90
@@ -76,10 +76,6 @@ module coordinates
   real, save :: zmax = 1.0d0
   real, save :: zlen = 1.0d0
 
-! the effective resolution of the full domain
-!
-  integer,dimension(3), save :: effres  = 1
-
 ! the block coordinates for all levels of refinement
 !
   real, dimension(:,:), allocatable, save :: ax  , ay  , az
@@ -313,10 +309,6 @@ module coordinates
       rm(2) = cm(2) * ff
       rm(3) = cm(3) * ff
 
-! the effective resolution
-!
-      effres(1:NDIMS) = rm(1:NDIMS)
-
 ! the top level block division
 !
       dm(1) = rm(1) / in
diff --git a/src/mesh.F90 b/src/mesh.F90
index 3d792e1..ec739bb 100644
--- a/src/mesh.F90
+++ b/src/mesh.F90
@@ -258,7 +258,7 @@ module mesh
 !
     use blocks         , only : ndims, block_meta, list_meta
     use blocks         , only : get_mblocks, get_nleafs
-    use coordinates    , only : ng, nd, im, jm, km, toplev, effres
+    use coordinates    , only : ng, nd, in, jn, kn, im, jm, km, ir, jr, kr, toplev
     use mpitools       , only : master, nprocs
 
 ! local variables are not implicit by default
@@ -273,7 +273,7 @@ module mesh
 ! local variables
 !
     integer(kind=4) :: l, n
-    real(kind=8)    :: cv, ef
+    real(kind=8)    :: cv, ef, ff
 
 ! local pointers
 !
@@ -340,11 +340,12 @@ module mesh
 
 ! prepare coverage and efficiency factors
 !
+          ff  = 2**(toplev - 1)
           fcv = 1.0d+00 / n
-          fef = 1.0d+00 * im / (effres(1) + nd)
-          fef =     fef * jm / (effres(2) + nd)
+          fef = 1.0d+00 * im / (ir * in * ff + nd)
+          fef =     fef * jm / (jr * jn * ff + nd)
 #if NDIMS == 3
-          fef =     fef * km / (effres(3) + nd)
+          fef =     fef * km / (kr * kn * ff + nd)
 #endif /* NDIMS == 3 */
 
 ! reset the first execution flag