IPv4 subnet calculator

Related tools

• IPv4 subnet splitter Divide a parent IPv4 range into equal-sized child CIDR blocks.
• CIDR to IP range calculator Convert an IPv4 or IPv6 CIDR block to its first and last address, netmask, wildcard mask and address counts.
• Subnet mask and prefix length chart Look up the subnet mask, wildcard mask, address count and usable hosts for every IPv4 prefix length from /0 to /32, plus common IPv6 prefixes.
• CIDR overlap checker Compare IPv4 and IPv6 networks before assigning routes or planning a change.
• IP address lookup and blocklist check See your public IP address, then look up any IP address or domain: reverse DNS, forward-confirmed reverse DNS, network owner and ASN, and a check against a small set of public DNS blocklists.

Guides and articles

• Subnet mask, CIDR and prefix length guide
• IPv4 subnet calculator: plan a network range (article)