IP Range Lookup
Enter an IPv4 address with CIDR notation to calculate its network range, subnet mask and usable hosts.
What is an IP range lookup?
An IP range lookup calculates the network boundaries represented by an IPv4 address and CIDR prefix. It shows how a CIDR block is divided into network, broadcast and host addresses and helps explain exactly which IPv4 addresses belong to the same subnet.
CIDR notation combines an IP address with a prefix such as /24, /28 or /32. The prefix specifies how many bits identify the network portion of the address, while the remaining bits determine the size of the address range.
How to use IP Range Lookup
- Enter an IPv4 address with a CIDR prefix, such as 192.168.1.10/24.
- Run the range calculation.
- Review the normalized network, broadcast address, subnet mask, usable host range and total address count.
Understanding CIDR and IP range results
The network address represents the beginning of the subnet, while the broadcast address normally represents its final address. The subnet mask expresses the same network boundary in dotted-decimal form.
Traditional IPv4 subnets reserve the network and broadcast addresses, so usable host counts are generally smaller than the total address count. Point-to-point /31 networks are treated according to RFC 3021, while a /32 represents one individual IPv4 address.
Common uses for IP range calculations
- Determine whether two IPv4 addresses belong to the same subnet.
- Calculate usable hosts when designing a network.
- Verify CIDR blocks used in firewall or access-control rules.
- Understand network and broadcast addresses.
- Check address ranges before configuring routers, VPNs or servers.