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Digital, Internet & Technology

IPv4 Subnet Calculator

Calculate an IPv4 subnet’s network and broadcast addresses, usable host range, host count, masks and address type from an IP and prefix.

Your inputs

Results

Network (CIDR)

192.168.1.128/26

Network address
192.168.1.128
Broadcast address
192.168.1.191
Usable host range
192.168.1.129 – 192.168.1.190
Usable hosts
62
Total addresses
64
Subnet mask
255.255.255.192
Wildcard mask
0.0.0.63
Historical class
C
Address type
Private (RFC 1918)
Address in binary
11000000.10101000.00000001.10000010

✓Exact calculation — rounded only for display

Notes for this result

  • Computed entirely in your browser; no address is sent anywhere.

What this calculator does

Subnetting divides an address space into smaller networks. Enter an address with a /prefix to see every key value.

Formula and method

Network = IP AND mask; Broadcast = network OR wildcard; Usable hosts = 2^(32 − prefix) − 2 (except /31 and /32)

Worked example

Calculated by this tool with its default inputs:

Inputs

  • IP address (optionally with /prefix): 192.168.1.130/26
  • Prefix length (if not given above): 24

Results

  • Network (CIDR): 192.168.1.128/26
  • Network address: 192.168.1.128
  • Broadcast address: 192.168.1.191
  • Usable host range: 192.168.1.129 – 192.168.1.190
  • Usable hosts: 62
  • Total addresses: 64

How to read the results

Address type shows private, public or special-purpose ranges.

Assumptions and limitations

  • Calculated entirely in your browser — addresses and values are never sent to a server.
  • Leading zeros (e.g. 192.168.01.1) are rejected because some systems read them as octal.

Questions

Why are there two fewer usable hosts?

The network and broadcast addresses cannot be assigned to hosts, except on /31 point-to-point links.

Sources

Methodology and verification

Result type
Exact mathematical calculation (rounded only for display)
Formula version
1.0
Automated verification
7 reference and validation test cases, checked against independently computed values. The site cannot be built if any of them fail.
Editorial review
Awaiting human editorial review. The explanation was drafted with AI assistance; the formula and examples are verified by the automated tests above.

Privacy

Everything you enter is calculated in this browser and is not sent to Numerith or anyone else. Inputs are added to a share link only if you choose to include them. Privacy policy