IP Subnet Calculator

IPv4 Subnet Calculator

Enter an IP address with CIDR prefix or subnet mask. Optionally enter a second subnet mask to calculate subnets.

IP Address / CIDR

Enter IP address and select prefix length (e.g. 192.168.1.0 / 24)

Or Subnet Mask

Alternative to CIDR — overrides prefix if filled

Network Class Filter

Second Mask (Subnetting, optional)

For subnet splitting — must be larger than first mask

IPv6 Subnet Calculator

Calculate IPv6 subnet information including network address, host range, and address count.

IPv6 Address

Full or compressed IPv6 address (e.g. 2001:0db8:85a3::8a2e:0370:7334)

Prefix Length

REF

IPv4 Subnet Reference Table

Complete reference of all IPv4 prefix lengths with their subnet masks, wildcard masks, and usable host counts.

Prefix	Subnet Mask	Wildcard Mask	Usable Hosts	Class