diff --git a/docs/reference/cluster/stats.asciidoc b/docs/reference/cluster/stats.asciidoc
index 26b3553c3c17f..0dd73219cd1cf 100644
--- a/docs/reference/cluster/stats.asciidoc
+++ b/docs/reference/cluster/stats.asciidoc
@@ -227,6 +227,10 @@ space of deleted Lucene documents when a segment is merged.
 `total_size_in_bytes`::
 (integer)
 Total size in bytes across all primary shards assigned to selected nodes.
+
+`total_size`::
+(string)
+Total size across all primary shards assigned to selected nodes, as a human-readable string.
 =====
 
 `store`::
@@ -1600,6 +1604,7 @@ The API returns the following response:
          "count": 10,
          "deleted": 0,
          "total_size_in_bytes": 8833
+         "total_size": "8.6kb"
       },
       "store": {
          "size": "16.2kb",
diff --git a/rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/cluster.stats/10_basic.yml b/rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/cluster.stats/10_basic.yml
index 283125832254e..9e9461186fc2f 100644
--- a/rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/cluster.stats/10_basic.yml
+++ b/rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/cluster.stats/10_basic.yml
@@ -33,13 +33,13 @@
 ---
 "cluster stats with human flag returns docs as human readable size":
   - requires:
+      test_runner_features: [capabilities]
       capabilities:
         - method: GET
           path: /_cluster/stats
           capabilities:
             - "human-readable-total-docs-size"
-      test_runner_feature: [capabilities]
-      reason: Capability required to run test
+      reason: "Capability required to run test"
 
   - do:
       index:
@@ -53,8 +53,8 @@
       cluster.stats:
         human: true
 
-  - is_true: indices.docs.total_size_in_bytes
-  - is_true: indices.docs.total_size
+  - exists: indices.docs.total_size_in_bytes
+  - exists: indices.docs.total_size
 
 ---
 "get cluster stats returns cluster_uuid at the top level":
diff --git a/x-pack/plugin/monitoring/src/test/java/org/elasticsearch/xpack/monitoring/collector/indices/IndicesStatsMonitoringDocTests.java b/x-pack/plugin/monitoring/src/test/java/org/elasticsearch/xpack/monitoring/collector/indices/IndicesStatsMonitoringDocTests.java
index c6f02637a8bde..0d1a0374d4fc3 100644
--- a/x-pack/plugin/monitoring/src/test/java/org/elasticsearch/xpack/monitoring/collector/indices/IndicesStatsMonitoringDocTests.java
+++ b/x-pack/plugin/monitoring/src/test/java/org/elasticsearch/xpack/monitoring/collector/indices/IndicesStatsMonitoringDocTests.java
@@ -180,7 +180,7 @@ public void testToXContent() throws IOException {
 
     private CommonStats mockCommonStats() {
         final CommonStats commonStats = new CommonStats(CommonStatsFlags.ALL);
-        commonStats.getDocs().add(new DocsStats(1L, 0L, randomNonNegativeLong()));
+        commonStats.getDocs().add(new DocsStats(1L, 0L, randomNonNegativeLong() >> 8)); // >> 8 to avoid overflow - we add these things up
         commonStats.getStore().add(new StoreStats(2L, 0L, 0L));
 
         final IndexingStats.Stats indexingStats = new IndexingStats.Stats(3L, 4L, 0L, 0L, 0L, 0L, 0L, 0L, true, 5L, 0, 0);