💾

Drive Partition Calculator

Calculate the exact Megabytes (MB) required to get a perfectly round Gigabyte (GB) partition in Windows.

⬇️

How to Create a Perfect Drive Partition?

If you've ever tried to create a 100GB partition in Windows Disk Management by simply typing "100,000 MB", you probably ended up with an annoying 97.6 GB drive. Our Drive Partition Calculator fixes this math for you.

  1. Enter your desired size: Type the exact Gigabytes (GB) you want your new drive letter (like D: or E:) to show.
  2. Calculate the offset: Windows reads storage in Gibibytes (GiB) where 1 GB = 1024 MB. Click calculate to get the exact conversion.
  3. Copy the MB value: Copy the generated Megabyte (MB) value.
  4. Use Disk Management: Paste this exact number into the "Enter the amount of space to shrink in MB" field in the Windows Disk Management tool.

Frequently Asked Questions (FAQ)

Why do I need a calculator for a hard drive partition?

Windows operating systems calculate storage size using the binary system, meaning 1 Gigabyte (GB) equals exactly 1024 Megabytes (MB). Hard drive manufacturers use the decimal system (1 GB = 1000 MB). To force Windows to display a nice, round number (like 50GB or 100GB), you must multiply your target GB by 1024.

How do I get exactly a 100GB partition?

To get a perfectly round 100GB partition in Windows, you cannot enter 100,000 MB. You must enter exactly 102400 MB. Simply type "100" into our calculator above, and we will do the math for you.

Does this work for SSDs, HDDs, and NVMe drives?

Yes! Regardless of whether you are partitioning an old mechanical Hard Disk Drive (HDD), a SATA Solid State Drive (SSD), or a blazing-fast NVMe M.2 drive, Windows Disk Management uses the exact same mathematical formula.