IPv4 Subnet Calculator (CIDR)
Calculate network address, broadcast, usable host range, subnet mask, wildcard mask and host count from any IPv4 address and CIDR prefix.
Runs on your device
Result
Results appear here as you type.
What it does
Enter an address with a prefix (10.0.5.17/22) or a dotted mask. Results follow RFC 950 and RFC 3021, so /31 and /32 are handled as point to point and single host networks.
How to use it
- Enter an IP with /prefix or a subnet mask.
- Read the network details.
- Copy the range for firewall rules or router configuration.
Example
10.0.5.17/22 is in network 10.0.4.0 with hosts 10.0.4.1 to 10.0.7.254. Select Try an example above to see it.
When it helps
- Networking coursework and CCNA practice.
- Cloud VPC and firewall planning.
- Router and DHCP configuration.
Questions
Why are two addresses not usable?
The network and broadcast addresses are reserved in traditional subnets. /31 links use both addresses.
Does it support IPv6?
Not yet; IPv4 only.
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