Dual Boot Planning Tool

Disk Partition Size Calculator

Estimate safe partition sizes for Windows and Linux before installation.

Input your disk details

All values are in GB. Use real values from Disk Management for best accuracy.

Total disk size

Current Windows used space

Space to keep for Windows

Windows total: 240 GB (140 + 100)

System RAM size

Linux usage profile

This gives you a practical starting point. You can fine-tune during installation.

Windows (keep)

Linux root (/)

Linux swap

Linux home (/home)

Unallocated/free

Windows Root Swap Home Free

Keep at least 20 to 30 GB free on Windows for updates and recovery.
Back up important files before resizing partitions.
If dual boot is your first time, start with automatic installer options where possible.