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IPv4 Calculator

Compute subnet, mask, broadcast and usable hosts.

What Is a IPv4 Calculator?

The IPv4 Calculator computes the subnet information for any IPv4 address and prefix length. It shows the subnet mask, wildcard mask, network address, broadcast address, first and last usable hosts, and the total and usable host counts. This free online security tool is useful for IPv4 subnet calculator, IPv4 calculator, subnet mask calculator. Common use cases include network planning, subnetting, network address calculation, broadcast addresses, and usable host ranges. It is designed for quick browser-based analysis and development workflows. Security checks are signals rather than guarantees, so production systems should also be validated against current standards and their specific threat model.

How to Use This IPv4 Calculator

  1. 1
    Enter the network informationProvide the IP address, prefix length, or CIDR block.
  2. 2
    Set the prefixChoose the subnet size that matches your network design.
  3. 3
    Calculate the rangeRun the calculator to derive network and host information.
  4. 4
    Review reserved addressesFor IPv4, check network and broadcast addresses and the resulting usable host range.
  5. 5
    Apply the resultUse the calculated ranges for routing, VLANs, firewall rules, or network documentation.

Frequently Asked Questions

The broadcast address is the last address in a subnet, used to send packets to all hosts on that subnet at once. It cannot be assigned to a single host.
Usable hosts are the addresses between the network address and the broadcast address. For a /24 subnet there are 254 usable addresses (256 minus 2).
The wildcard mask is the inverse of the subnet mask and is used in access-control lists and routing to match a range of addresses.

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