How Much Free Space Should Be on C Drive
I bought a new PC, and it only got a 1TB C drive on the disk. I plan to create a D drive to store my personal files and some apps. How much free space should be on the C drive so that it won’t harm system performance and speed? Appreciate for any answers!
Best Answered by
Oliver· Answered on May 07, 2026
Generally, it is best to leave 10–20% free space on your C drive to ensure optimal performance. However, various factors such as computer usage habits, hardware health conditions, and software quantity can affect its performance.
If you plan to install plenty of applications on your PC, the C drive may need more free space. In addition, operations like video editing, 3D modeling, etc., generate a large number of cache files. So you need more free space to avoid C drive running out of space and causing trouble on your PC.
I recommend you download a practical disk manager tool - EaseUS Partition Master Free, to monitor the condition of the disks and partitions on your PC.
It provides multiple features for checking disk usage and managing your drives. It can help you extend the C drive in different ways so that you don't need to worry, even if it is almost full. You can use it to split the C drive and specify the space size of the C drive and D drive. The following page contains more details.
Further Reading: How to Split C Drive in Windows 11/10/8/7
