Subnet Calculator

Subnet Calculator helps you explore the stated math question. Start with the labelled inputs, then review the method, worked example and limitations before using a result.

Enter your values in the calculator fields to get an instant result.

Calculator guide

Subnet Calculator helps you explore the stated math question. Start with the labelled inputs, then review the method, worked example and limitations before using a result.

Formula or method

An IPv4 CIDR prefix selects the network bits. Network address = address AND mask; broadcast = network OR inverted mask. For ordinary subnets, usable hosts = 2^(32−prefix)−2.

How to use this calculator

  1. Enter the IPv4 address and prefix length.
  2. Review the network, broadcast and host range against the intended prefix.

Worked example

192.168.1.10/24 belongs to network 192.168.1.0, mask 255.255.255.0, and broadcast 192.168.1.255; the usual usable range is .1 through .254.

Understanding the result

Compare the output with the subnet calculator worked example using exactly the same inputs. A different assumption or rounding convention can produce a different displayed result; the output does not establish personal or professional suitability.

Limitations and assumptions

  • The tool uses conventional host counts. /31 point-to-point and /32 host-route behavior needs separate interpretation; it is not an IPv6 calculator.
  • The worked example demonstrates the stated assumptions, not a recommendation about your personal circumstances.

Frequently asked questions

Which inputs should I check first?

Follow the Subnet Calculator input instructions above. Check each measurement, date, selection or expression before comparing results.

Why might my result differ from another tool?

Compare the other tool's subnet calculator method, input units, rounding and assumptions. A matching title does not guarantee that both tools answer the same question.

Does a linked reference certify this result?

No. A reference can explain a formula or provide background for Subnet Calculator, but it does not endorse this website, validate personal inputs or establish professional suitability.

Sources

Educational and planning information only. Sources are attributed background or formula references, not endorsements. Verify consequential decisions with an appropriate qualified professional.