diff --git a/src/ol/source/vector.js b/src/ol/source/vector.js
index ee3c9ad205..e1e88b30cf 100644
--- a/src/ol/source/vector.js
+++ b/src/ol/source/vector.js
@@ -610,11 +610,13 @@ ol.source.Vector.prototype.getClosestFeatureToCoordinate = function(coordinate,
  *
  * This method is not available when the source is configured with
  * `useSpatialIndex` set to `false`.
+ * @param {ol.Extent=} opt_extent Destination extent. If provided, no new extent
+ *     will be created. Instead, that extent's coordinates will be overwritten.
  * @return {!ol.Extent} Extent.
  * @api
  */
-ol.source.Vector.prototype.getExtent = function() {
-  return this.featuresRtree_.getExtent();
+ol.source.Vector.prototype.getExtent = function(opt_extent) {
+  return this.featuresRtree_.getExtent(opt_extent);
 };
 
 
diff --git a/src/ol/structs/rbush.js b/src/ol/structs/rbush.js
index c49496e3a7..0828832452 100644
--- a/src/ol/structs/rbush.js
+++ b/src/ol/structs/rbush.js
@@ -213,5 +213,5 @@ ol.structs.RBush.prototype.clear = function() {
 ol.structs.RBush.prototype.getExtent = function(opt_extent) {
   // FIXME add getExtent() to rbush
   var data = this.rbush_.data;
-  return [data.minX, data.minY, data.maxX, data.maxY];
+  return ol.extent.createOrUpdate(data.minX, data.minY, data.maxX, data.maxY, opt_extent);
 };