This online application is free and designed to convert KML to KMZ file format. The KMZ format requires less space than KML. This format is a good choice for transferring geo data over the Internet. However, for geoprocessing tasks, KMZ is suboptimal because it takes time to unzip.
Conversion App is a free application provided by Aspose.Gis
KML (Keyhole Markup Language) contains geospatial information in XML notation. KML can be opened in Geographic Information System (GIS) applications provided they support it. Many applications have started providing support for KML format after it has been adopted as international standard.