diff --git a/common/metrics/defs.go b/common/metrics/defs.go
index 11da0c184b8..16a2bd13660 100644
--- a/common/metrics/defs.go
+++ b/common/metrics/defs.go
@@ -2930,6 +2930,8 @@ const (
 	ShardDistributorAssignLoopSuccess
 	ShardDistributorAssignLoopFail
 
+	ShardDistributorActiveShards
+
 	ShardDistributorStoreExecutorNotFound
 	ShardDistributorStoreFailuresPerNamespace
 	ShardDistributorStoreRequestsPerNamespace
@@ -3702,6 +3704,8 @@ var MetricDefs = map[ServiceIdx]map[MetricIdx]metricDefinition{
 		ShardDistributorAssignLoopSuccess:               {metricName: "shard_distrubutor_shard_assign_success", metricType: Counter},
 		ShardDistributorAssignLoopFail:                  {metricName: "shard_distrubutor_shard_assign_fail", metricType: Counter},
 
+		ShardDistributorActiveShards: {metricName: "shard_distributor_active_shards", metricType: Gauge},
+
 		ShardDistributorStoreExecutorNotFound:             {metricName: "shard_distributor_store_executor_not_found", metricType: Counter},
 		ShardDistributorStoreFailuresPerNamespace:         {metricName: "shard_distributor_store_failures_per_namespace", metricType: Counter},
 		ShardDistributorStoreRequestsPerNamespace:         {metricName: "shard_distributor_store_requests_per_namespace", metricType: Counter},
diff --git a/common/metrics/tags.go b/common/metrics/tags.go
index 9ee9e0aecb5..071e5680dd7 100644
--- a/common/metrics/tags.go
+++ b/common/metrics/tags.go
@@ -347,6 +347,10 @@ func NamespaceTag(namespace string) Tag {
 	return metricWithUnknown("namespace", namespace)
 }
 
+func NamespaceTypeTag(namespaceType string) Tag {
+	return metricWithUnknown("namespace_type", namespaceType)
+}
+
 func TaskCategoryTag(category string) Tag {
 	return metricWithUnknown("task_category", category)
 }
diff --git a/service/sharddistributor/leader/process/processor.go b/service/sharddistributor/leader/process/processor.go
index 60421952ec0..f6befdfa0f1 100644
--- a/service/sharddistributor/leader/process/processor.go
+++ b/service/sharddistributor/leader/process/processor.go
@@ -325,6 +325,15 @@ func (p *namespaceProcessor) rebalanceShardsImpl(ctx context.Context, metricsLoo
 		return fmt.Errorf("assign shards: %w", err)
 	}
 
+	totalActiveShards := 0
+	for _, assignedState := range namespaceState.ShardAssignments {
+		totalActiveShards += len(assignedState.AssignedShards)
+	}
+	metricsLoopScope.Tagged(
+		metrics.NamespaceTag(p.namespaceCfg.Name),
+		metrics.NamespaceTypeTag(p.namespaceCfg.Type),
+	).UpdateGauge(metrics.ShardDistributorActiveShards, float64(totalActiveShards))
+
 	return nil
 }