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Subnet Calculator

Calculate network address, mask, broadcast, host range, and usable host count.

Inputs

Defaults are prefilled so the result is visible immediately.

IP address

CIDR prefix

Results

Results update as the calculator inputs change.

Network address

192.168.1.0/24

Subnet mask

255.255.255.0

Broadcast

192.168.1.255

First usable

192.168.1.1

Last usable

192.168.1.254

Usable hosts

254

Formula and Assumptions

Subnet mask is derived from CIDR prefix; network = IP AND mask; broadcast = network OR inverse mask.

/31 and /32 networks are shown without subtracting traditional network and broadcast host addresses.

Results are for IPv4 subnetting.

Reference Upgrade

Built from the Calculator.net model, with added context.

Live validation and instant result updates instead of a submit-only workflow.

Multiple decision metrics are shown together, not only the primary answer.

Formula notes and assumptions are visible on the page so the math is easier to audit.

Reference Model

Modeled after the input style and primary output on Calculator.net's Subnet Calculator.

The page keeps the math in one place and exposes the assumptions beside the result.

Default inputs: ipAddress=192.168.1.42, cidr=24