Disk Partition Calculator - Get Partition Size in MB

Disk Partition Size Calculator for Windows. Enter disk size and get partition size suggestions for NTFS and FAT32. Get whole-number partition sizes in GB and MB.



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Note: This tool provides *suggested* sizes for planning purposes only. Actual usable disk space will be slightly less due to formatting overhead (MB/GB conversion) and system reserved space.

Windows Disk Partition Guide (Simple & Beginner Friendly)

Partition Size Examples (Based on Total Disk Size)

Total Disk Size Ideal C: Ideal D: Ideal E: Notes
256 GB 120 GB 70 GB 60 GB Light use
512 GB 150 GB 150 GB 200 GB Balanced
1 TB 200 GB 300 GB 500 GB Best for most
2 TB 250 GB 500 GB 1 TB Power users

Recommended C: drive size: 150–200 GB (250 GB+ for heavy users).

What Is Disk Partitioning?

Disk partitioning means dividing your hard disk into separate sections like C:, D:, and E:. It helps keep your operating system, software, and personal files organized.

How to Make a Disk Partition (Windows 10 & Windows 11)

Step 1 – Open Disk Management

Right-click the Start Menu and select Disk Management.

Step 2 – Shrink Your Main Drive (Usually C:)

Right-click the C: drive, click Shrink Volume, enter the amount of space you want to shrink, and click Shrink.

Step 3 – Create a New Partition

Find the Unallocated Space, right-click it, select New Simple Volume, choose the drive letter, format as NTFS, and complete the setup.

How Many Partitions Are Best?

For most users, three to four partitions are ideal:

This setup keeps your system fast and organized.

Minimum Space for Windows C Drive

Recommended sizes for Windows 10 and Windows 11:

How Much Space to Actually Give Each Partition

General guidance drawn from how Windows 10/11 setup and storage actually behave — not hard limits, but sensible defaults.

Give the Windows (C:) partition at least 120 GB, ideally 150–200 GB

Windows 11 setup requires a minimum of ~64 GB free, but updates, drivers, temp files, hibernation, and a growing pagefile eat into that fast. 100 GB is survivable; anything under that leads to constant "low disk space" warnings within a year.

Don't split a small SSD (under ~250 GB) into more than two partitions

Every partition needs its own free-space buffer for the drive to stay fast and for TRIM to work well. On a small drive, splitting three or four ways just means every partition runs low at once.

Give the Windows (C:) partition at least 120 GB, ideally 150–200 GB

Windows 11 setup requires a minimum of ~64 GB free, but updates, drivers, temp files, hibernation, and a growing pagefile eat into that fast. 100 GB is survivable; anything under that leads to constant "low disk space" warnings within a year.

Leave the EFI, MSR, and Recovery partitions alone

Windows creates these automatically during setup — a ~260–300 MB EFI system partition, a 16 MB Microsoft Reserved partition, and a 500 MB–2 GB recovery partition. They're not shown in "This PC" on purpose. Resizing or deleting them can break booting or Windows Update, and their size is exactly why usable space differs PC to PC.

Keep roughly 10–15% of every partition free

SSDs slow down and Windows Update can fail when a volume gets nearly full. Size partitions for what you'll store plus headroom, not for the exact total you have today.

Two partitions covers most people: C: for Windows and apps, D: for files

Keeping personal files on a separate partition means you can reinstall Windows on C: without touching your data. Add a third partition only if you have a distinct, large category — a game library, a media archive, or a backup target.

Built as a planning aid. Always confirm free space and back up important files before resizing a real partition in Disk Management.

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