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IP Subnet Calculator

IP Subnet Calculator works from the inputs you provide and returns network, subnet mask, broadcast, total addresses, usable hosts, first host, last host. Use the calculation panel to explore a scenario, then check the formula and limitations before applying the result.

Free to useBrowser-based calculationFormula & example ↓

Your inputs

Minimum: 0 · Maximum: 32 · Whole numbers

Your results

Enter your values and calculate to see the result.

Formula and calculation method

Address count = 2^(32−prefix). Network = address AND mask. Broadcast = network + count − 1.

/31 includes both point-to-point addresses; /32 identifies one host. IPv6 is not supported.

How to use ip subnet calculator

  1. Set IPv4 address. The example below uses 192.168.1.10.
  2. Set CIDR prefix. The example below uses 24.
  3. Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.

Worked example

Example inputs
IPv4 address
192.168.1.10
CIDR prefix
24
Network
192.168.1.0/24
Subnet mask
255.255.255.0
Broadcast
192.168.1.255
Total addresses
256
Usable hosts
254
First host
192.168.1.1
Last host
192.168.1.254

Factors affecting your result

/31 includes both point-to-point addresses; /32 identifies one host. IPv6 is not supported.

Changing ipv4 address changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.

Frequently asked questions

How does the ip subnet calculator work?

Address count = 2^(32−prefix). Network = address AND mask. Broadcast = network + count − 1.

What inputs does IP Subnet Calculator need?

Enter ipv4 address, cidr prefix. Choose values that correspond to the same situation and measurement convention.

How should I interpret the ip subnet calculator result?

/31 includes both point-to-point addresses; /32 identifies one host. IPv6 is not supported.

Are my ip subnet calculator inputs uploaded?

No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.

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