diff --git a/src/ol/sphere/sphere.js b/src/ol/sphere/sphere.js
index a3b4799efc..96a7b68c2b 100644
--- a/src/ol/sphere/sphere.js
+++ b/src/ol/sphere/sphere.js
@@ -15,6 +15,17 @@ goog.require('goog.math');
 
 
 /**
+ * @classdesc
+ * Class to create objects that can be used with {@link
+ * ol.geom.Polygon.circular}.
+ *
+ * For example to create a sphere whose radius is equal to the semi-major
+ * axis of the WGS84 ellipsoid:
+ *
+ * ```js
+ * var wgs84Sphere= new ol.Sphere(6378137);
+ * ```
+ *
  * @constructor
  * @param {number} radius Radius.
  * @api