You can install Quicken (either the Windows or Mac version) on up to three computers in the same household, as described in their respective Quicken End User License Agreements.
You do not have to purchase additional copies of Quicken to install it on the second and third computer.
If you purchased a CD, you can use that same Quicken CD to install Quicken on up to three computers in your household. The installation will work just as the first installation did.
If you purchased a download, you can log in to your Quicken.com account from up to three different computers and download Quicken. The steps for this can be found here.
Note: we don't recommend sharing or attempting to sync Quicken data files between computers, as this may lead to data file damage. Our Quicken Mobile App will allow you to view your synced Quicken accounts from several different mobile devices, if you choose.
If you need assistance locating your download, or if you are attempting to install from a CD and do not have access to a CD/DVD drive, you can contact Quicken Support.
For help installing Quicken, review these FAQs:
How to Install Quicken for Windows
Getting Started with Quicken for Mac 2017