Network

Subnet Calculator

Calculate network, broadcast, host range, and mask details from CIDR.

Last validated: 2026-02-14

Subnet Calculator derives network address, broadcast, host range, and mask details from CIDR input. It is useful for address planning, firewall rule scoping, and onboarding new segments. The tool reduces manual binary math errors when carving networks. Use it as a fast validation step before provisioning.

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Input Pattern

Enter values in the left panel, keep units explicit, run the calculation, then copy or share the result. Invalid fields are highlighted immediately.

Subnet Input

Result

Network: 192.168.10.0/24

Subnet mask: 255.255.255.0

Wildcard: 0.0.0.255

Broadcast: 192.168.10.255

First host: 192.168.10.1

Last host: 192.168.10.254

Usable hosts: 254

How to use this tool

Enter a CIDR block such as `10.20.0.0/24`.
Run the calculator to view network boundaries and host range.
Confirm values match your intended segmentation before deployment.

Worked Example

Auto-generated from the tool's current default or entered inputs.

Example Inputs

Cidr: 192.168.10.25/24
Ip: 192.168.10.25
Prefix: 24
Subnet mask: 255.255.255.0
Wildcard mask: 0.0.0.255
Network: 192.168.10.0
Broadcast: 192.168.10.255
First host: 192.168.10.1

Expected Outputs

Prefix: 24
Host count: 254

Interpretation

Prefix is 24. Use this as a decision input, not as a standalone conclusion.
Host count is 254. Use this as a decision input, not as a standalone conclusion.
Confirm unit consistency and operational constraints before applying this result in production or field conditions.

Scenario Compare (A vs B)

Use this to compare two input sets and quantify change in key outputs.

Scenario A

Cidr

Prefix

Subnet mask

Wildcard mask

Network

Broadcast

First host

Scenario B

Cidr

Prefix

Subnet mask

Wildcard mask

Network

Broadcast

First host

Formula References

IPv4/IPv6 addressing rules and common protocol arithmetic.
DNS/WHOIS/network calls depend on external resolvers and current network state.

Assumptions

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