Calculate available capacity across multiple mount points sharing an underlying volume.
When a single disk is carved into separate mount points (either as distinct partitions or LVM logical volumes), each mount point's capacity is a fixed share of the underlying device — unlike directories on a shared filesystem, exceeding one mount point's allocation doesn't borrow from another. This calculator distributes total disk capacity across the standard Linux mount points (/boot, /, /home, /var, /tmp) by percentage share so you can plan partition sizes before running fdisk, parted or lvcreate.
Per-mount capacity
mount_capacity = total_capacity × allocation_percent
/var holds logs, package caches and spool files that can grow unexpectedly (e.g. a runaway log). Isolating it on its own partition means a full /var can't consume all free space on / and crash the root filesystem or prevent login.
/boot typically only needs 500MB-1GB even on modern systems, since it holds kernel images, initramfs and bootloader files. Percentage-based sizing works for planning, but /boot is usually better set to a fixed size regardless of total disk capacity.
No — swap space is a distinct partition type (or swap file) that isn't mounted into the directory tree, so it's sized separately. Use the Swap Size Calculator or Swap Partition Calculator for that allocation.