diff --git a/api/src/org/apache/cloudstack/api/command/admin/offering/CreateDiskOfferingCmd.java b/api/src/org/apache/cloudstack/api/command/admin/offering/CreateDiskOfferingCmd.java
index 7c28fd7e994..747da053be6 100644
--- a/api/src/org/apache/cloudstack/api/command/admin/offering/CreateDiskOfferingCmd.java
+++ b/api/src/org/apache/cloudstack/api/command/admin/offering/CreateDiskOfferingCmd.java
@@ -43,7 +43,7 @@ public class CreateDiskOfferingCmd extends BaseCmd {
     //////////////// API parameters /////////////////////
     /////////////////////////////////////////////////////
 
-    @Parameter(name = ApiConstants.DISK_SIZE, type = CommandType.LONG, required = false, description = "size of the disk offering in GB")
+    @Parameter(name = ApiConstants.DISK_SIZE, type = CommandType.LONG, required = false, description = "size of the disk offering in GB (1GB = 1,073,741,824 bytes)")
     private Long diskSize;
 
     @Parameter(name = ApiConstants.DISPLAY_TEXT, type = CommandType.STRING, required = true, description = "alternate display text of the disk offering", length = 4096)