diff --git a/cluster/aws/config-default.sh b/cluster/aws/config-default.sh
index 610f656f9cb..79037c59de2 100644
--- a/cluster/aws/config-default.sh
+++ b/cluster/aws/config-default.sh
@@ -15,10 +15,33 @@
 # limitations under the License.
 
 ZONE=${KUBE_AWS_ZONE:-us-west-2a}
-MASTER_SIZE=${MASTER_SIZE:-t2.micro}
-MINION_SIZE=${MINION_SIZE:-t2.micro}
+MASTER_SIZE=${MASTER_SIZE:-}
+MINION_SIZE=${MINION_SIZE:-}
 NUM_MINIONS=${NUM_MINIONS:-4}
 
+# Dynamically set node sizes so that Heapster has enough space to run
+if [[ -z ${MINION_SIZE} ]]; then
+  if (( ${NUM_MINIONS} < 50 )); then
+    MINION_SIZE="t2.micro"
+  elif (( ${NUM_MINIONS} < 150 )); then
+    MINION_SIZE="t2.small"
+  else
+    MINION_SIZE="t2.medium"
+  fi
+fi
+
+# Dynamically set the master size by the number of nodes, these are guesses
+# TODO: gather some data
+if [[ -z ${MASTER_SIZE} ]]; then
+  if (( ${NUM_MINIONS} < 50 )); then
+    MASTER_SIZE="t2.micro"
+  elif (( ${NUM_MINIONS} < 150 )); then
+    MASTER_SIZE="t2.small"
+  else
+    MASTER_SIZE="t2.medium"
+  fi
+fi
+
 # Optional: Set AWS_S3_BUCKET to the name of an S3 bucket to use for uploading binaries
 # (otherwise a unique bucket name will be generated for you)
 #  AWS_S3_BUCKET=kubernetes-artifacts
diff --git a/cluster/aws/config-test.sh b/cluster/aws/config-test.sh
index fc9d93e8c5e..63e8519bd1e 100755
--- a/cluster/aws/config-test.sh
+++ b/cluster/aws/config-test.sh
@@ -15,10 +15,35 @@
 # limitations under the License.
 
 ZONE=${KUBE_AWS_ZONE:-us-west-2a}
-MASTER_SIZE=${MASTER_SIZE:-t2.micro}
-MINION_SIZE=${MINION_SIZE:-t2.micro}
+
+MASTER_SIZE=${MASTER_SIZE:-}
+MINION_SIZE=${MINION_SIZE:-}
 NUM_MINIONS=${NUM_MINIONS:-2}
 
+# Dynamically set node sizes so that Heapster has enough space to run
+if [[ -z ${MINION_SIZE} ]]; then
+  if (( ${NUM_MINIONS} < 50 )); then
+    MINION_SIZE="t2.micro"
+  elif (( ${NUM_MINIONS} < 150 )); then
+    MINION_SIZE="t2.small"
+  else
+    MINION_SIZE="t2.medium"
+  fi
+fi
+
+# Dynamically set the master size by the number of nodes, these are guesses
+# TODO: gather some data
+if [[ -z ${MASTER_SIZE} ]]; then
+  if (( ${NUM_MINIONS} < 50 )); then
+    MASTER_SIZE="t2.micro"
+  elif (( ${NUM_MINIONS} < 150 )); then
+    MASTER_SIZE="t2.small"
+  else
+    MASTER_SIZE="t2.medium"
+  fi
+fi
+
+
 # Because regions are globally named, we want to create in a single region; default to us-east-1
 AWS_S3_REGION=${AWS_S3_REGION:-us-east-1}
 
diff --git a/cluster/aws/options.md b/cluster/aws/options.md
index 31a3b3ca6c2..9db6e60af01 100644
--- a/cluster/aws/options.md
+++ b/cluster/aws/options.md
@@ -29,7 +29,7 @@ AWS_S3_REGION is useful for people that want to control their data location, bec
 
 **MASTER_SIZE**, **MINION_SIZE**
 
-The instance type to use for creating the master/minion.  Defaults to t2.micro.
+The instance type to use for creating the master/minion.  Defaults to auto-sizing based on the number of nodes (see below).
 
 For production usage, we recommend bigger instances, for example:
 
@@ -38,6 +38,10 @@ export MASTER_SIZE=c4.large
 export MINION_SIZE=r3.large
 ```
 
+If you don't specify master and minion sizes, the scripts will attempt to guess the correct size of the master and worker nodes based on `${NUM_MINIONS}`.
+In particular for clusters less than 50 nodes it will 
+use a `t2.micro` for clusters between 50 and 150 nodes it will use a `t2.small` and for clusters with greater than 150 nodes it will use a `t2.medium`.
+
 Please note: `kube-up` utilizes ephemeral storage available on instances for docker storage. EBS-only instance types do not
 support ephemeral storage and will default to docker storage on the root disk which is usually only 8GB.
 EBS-only instance types include `t2`, `c4`, and `m4`.
diff --git a/docs/getting-started-guides/aws.md b/docs/getting-started-guides/aws.md
index 72a6bb8d13c..41d844047ed 100644
--- a/docs/getting-started-guides/aws.md
+++ b/docs/getting-started-guides/aws.md
@@ -91,6 +91,9 @@ export INSTANCE_PREFIX=k8s
 ...
 ```
 
+The scripts will attempt to guess the correct size of the master and worker nodes based on `${NUM_MINIONS}`, in particular for clusters less than 50 nodes it will
+use a `t2.micro` for clusters between 50 and 150 nodes it will use a `t2.small` and for clusters with greater than 150 nodes it will use a `t2.medium`.
+
 It will also try to create or reuse a keypair called "kubernetes", and IAM profiles called "kubernetes-master" and "kubernetes-minion".
 If these already exist, make sure you want them to be used here.