IPv6 Subnet Calculator

Enter an IPv6 address or prefix (e.g. 2001:db8::/48 or 2001:db8::1/64) to see the network, range, and address count with both compressed and fully expanded forms.

IPv6 Input

IPv6 address or prefix

Examples: 2001:db8::/32, 2001:db8:abcd:1::1/64, 2001:db8:: (assumes /64)

Subnet Summary

Hextet View — blue = networkgreen = interface

Representations

Compressed Network

Expanded Network

First Address

Last Address

Prefix Quick Reference

Prefix	Addresses	Addresses (2^n)	Common Use

How IPv6 Subnetting Works

IPv6 uses 128-bit addresses, written as eight 16-bit blocks in hexadecimal, separated by colons. A prefix length such as /64 indicates how many of those 128 bits belong to the network portion; the remaining bits identify individual interfaces.

Typical Prefix Lengths

/48: Commonly allocated to sites or customers. Contains 65,536 /64 subnets.
/56: Often used for smaller sites or residential customers. Contains 256 /64s.
/64: Standard LAN subnet size, required for SLAAC (stateless address autoconfiguration).
/128: Single interface address, similar to an IPv4 /32 host route.

Zero Compression

IPv6 allows a run of consecutive all-zero blocks to be compressed with :: once per address (for example, 2001:db8:0:0:0:0:0:1 becomes 2001:db8::1). This calculator shows both the canonical compressed form and the fully expanded form.