[1] It had over 40 million records[2] from around 90 libraries as of 2019,[3] representing a wide range of materials across all subject areas.

Copac was freely available to all,[2] and was widely used, with users mainly coming from Higher Education institutions in the United Kingdom, but also worldwide.

[5] These interfaces could be used to provide links to items on Copac from external sites, such as those used on the Institute of Historical Research website.

[7] The service used records supplied by RLUK members, as well as an increasing range of specialist libraries with collections of national research interest.

A full list of contributors is available[8] including the National Trust for Places of Historic Interest or Natural Beauty, the Royal Botanic Gardens, Kew, the Middle Temple library and Institution of Mechanical Engineers (IMechE) Library.