: Advanced versions take into account disk sector size (e.g., 512e or 4Kn) and cluster size to ensure the most accurate results. Recommended Free Tools (2026)

In this guide, we will break down why you need one, the mathematics behind disk sizing, and where to find the best free tools to get the job done right.

If you have ever tried to partition a hard drive, you know the frustration of "uneven" numbers. You enter 100 GB, but Windows shows 99.9 GB. This happens because of the way computers calculate binary data versus how we see decimal numbers.

Before you click that "download free" button, look for these three critical features:

Once you have your number, you can apply it using the built-in Windows tool: Search for Computer Management and run it as an administrator. Disk Management Right-click an unallocated region and select New Simple Volume