Use this calculator for fast subnetting checks, host-range lookups, and mask conversion without leaving the page.
Inputs
This topic also has a deeper guide and a printable reference pack, so you can move from the live answer into the method, assumptions, and worked examples without leaving the topic cluster.
A fuller printable subnetting pack covering CIDR, subnet masks, wildcard masks, host counts, and network boundaries with binary-first explanations and quick lookup logic.
A worked-examples pack for decoding prefixes, finding ranges, and planning practical IPv4 subnets from real host requirements rather than memorised tables alone.
These are the main values the calculator uses. Keep the units consistent and, where relevant, match the assumptions explained in the related guide.
Use any host address inside the subnet you want to inspect.
Enter the prefix length from 0 to 32 so the subnet boundary is clear.
Use this page when you need to check subnet boundaries, host ranges, or mask details for an IPv4 address and prefix.
The main result is the network address. Supporting values show the broadcast address, the first and last usable hosts, and the usable host count.
For 192.168.1.42/24, the network is 192.168.1.0 and the broadcast address is 192.168.1.255.
That makes the usable host range 192.168.1.1 to 192.168.1.254.
This calculator covers IPv4 only. It does not validate routing design, reserved-address policy, DHCP scope planning, or broader network architecture decisions.
No. This page is intentionally limited to IPv4 subnetting.
They show the usable range inside the subnet, which is often what you need when assigning devices or checking whether an address belongs to a network.
Use the CIDR from Subnet Mask Calculator to work out cidr from subnet mask for networking, storage, or systems planning.
Use the Subnet Mask from CIDR Calculator to work out subnet mask from cidr for networking, storage, or systems planning.
Use the Wildcard Mask from CIDR Calculator to work out wildcard mask from cidr for networking, storage, or systems planning.
Use the Subnet Host Count Calculator to work out subnet host count for networking, storage, or systems planning.