What this tool does
BrowserLocal
- Network and broadcast address.
- Mask and wildcard.
- Subnet splitting.
Privacy
Local tools run in the browser. API modules query only public targets and block private networks.
IPv4 subnet calculator
Calculate CIDR information, mask, broadcast, host range and split an IPv4 network.
Quick guide
Understanding CIDR
The CIDR prefix tells how many bits belong to the network. A /24 usually gives 256 addresses, including network and broadcast addresses.
Why calculate a subnet
It helps plan VLANs, document networks, split an IP range, or verify a gateway and usable range.
Local by design
IPv4 calculation requires no server call: the address stays in your browser.
Frequently asked questions
What is the difference between mask and CIDR?
CIDR is short notation like /24; the mask is decimal notation like 255.255.255.0.
What is a broadcast address?
It is the address used to reach all hosts in an IPv4 subnet.
Does the tool support IPv6?
This page focuses on IPv4. IPv6 rules are different and deserve a separate tool.