Yes, the CCC License allows you to install and use Carbon Copy Cloner on any computer that you own or control for personal, noncommercial use. If you're using CCC commercially or institutionally, check out our Corporate or Education Licensing options.
A CCC 4 license will also be accepted by CCC 3.5.7. If you have multiple Macs in your household and some do not meet the requirements for CCC 4, you can use the same license on all of your Macs with CCC 3.5.7 and CCC 4. You can download all available versions of CCC at any time from our download page. Misplaced your license? Request the registration key from within CCC or via our website.
To learn more about how to use the license on multiple Macs, please see How do I use CCC on multiple Macs in my household?