CIDR Calculator
Work out the network address, broadcast address, subnet mask, wildcard mask, and usable host range for any IPv4 CIDR block in a single step.
How to use
- Enter the block in CIDR notation.
- Read the network, broadcast, and mask rows.
- Note the usable host count for capacity planning.
A CIDR block such as 192.168.1.0/24 is described by a network address and a prefix length. This calculator expands that into the mask, broadcast, and host range you need when configuring a router, a firewall, or a cloud network.
Enter a CIDR block above.
Questions about cidr calculator
- What is the wildcard mask?
- The inverse of the subnet mask. It is what routing protocols use to match any address inside the block.
- How many hosts can I use?
- Total addresses minus the network and broadcast addresses. A 24 block gives 254 usable hosts.
- Why is there no broadcast address on a 31 or 32?
- Those sizes have no room for a network and broadcast address. RFC 3021 uses a 31 as a point-to-point link, and a 32 is a single host route.
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