CIDR Tools & Command Generator
Check CIDR membership, split a block, convert range↔CIDR, and generate curl/dig/PowerShell/ip commands for your input. All in your browser.
What these CIDR tools do
Three quick utilities that run entirely in your browser — nothing is sent to the server, so IPv6 input works even though our server is IPv4-only.
- CIDR membership — checks whether an IP falls inside a CIDR block (e.g. is
10.1.2.3inside10.1.0.0/16?). Useful for firewall rules, allowlists and log analysis. - Split CIDR — divides a block into equal smaller subnets at a new prefix length (e.g.
192.168.0.0/24into four/26s). Handy for VPC and VLAN planning. - Command generator — turns an IP or domain you type into ready-to-run
dig,nslookup,curl,Resolve-DnsName,Test-NetConnection,pingand RDAP commands for Linux/macOS and Windows.
For full network/broadcast/host math, use the Subnet Calculator. To convert between notations, see the IP Converter. Background: subnetting and CIDR basics.
Frequently asked questions
Does this tool support IPv6?
Yes. Membership and splitting both accept IPv6 (e.g. 2001:db8::/32). Because all calculation happens in your browser with BigInt arithmetic, there is no dependency on the server's IPv4-only network.
How many subnets can I split into?
The tool caps output at 1024 subnets to keep the page responsive. Choose a new prefix that is at most 10 bits longer than the original (e.g. /16 → /26) to stay within the limit.
Are the generated commands safe to run?
They are standard read-only diagnostic commands (DNS lookups, a HEAD request, a ping). Review any command before running it, and note that some networks rate-limit or block ICMP ping.