diff --git a/configs/default.config b/configs/default.config
index 19c541d..a123692 100644
--- a/configs/default.config
+++ b/configs/default.config
@@ -38,7 +38,7 @@ node_ram=4096
 # For a 32GB machine we'll get 10 VMs altogether
 # 1 x 4GB juju, 1 x 8GB controler, 8 x 4GB compute
 # The juju VM is not included in the count
-node_count=$(( `cat /proc/meminfo | grep -i memtotal | awk '{print $2}'` * 11 / 10 / 1024 / $node_ram + 1 ))
+node_count=$(( (( `cat /proc/meminfo | grep -i memtotal | awk '{print $2}'` - ( ${control_count} * ${control_ram} * 1024 )) * 11 / 10) / 1024 / ${node_ram} + (4*8/10) ))
 
 # Disks to create on each VM
 disks=()