IP Subnet Calculator

Calculate network address, broadcast, usable hosts, and wildcard mask from IP and CIDR notation.

By Konstantin Iakovlev · Updated April 2026 · Source: IETF

Usable Hosts

254

/24 network

Subnet Details

Network Address192.168.1.0
Broadcast Address192.168.1.255
Subnet Mask255.255.255.0
Wildcard Mask0.0.0.255
First Usable Host192.168.1.1
Last Usable Host192.168.1.254
Usable Hosts254
CIDR Notation192.168.1.0/24

Binary Subnet Mask

Mask11111111.11111111.11111111.00000000

Common Subnets Reference

/8255.0.0.0 (16,777,214 hosts)
/16255.255.0.0 (65,534 hosts)
/24255.255.255.0 (254 hosts)
/25255.255.255.128 (126 hosts)
/26255.255.255.192 (62 hosts)
/27255.255.255.224 (30 hosts)
/28255.255.255.240 (14 hosts)
/30255.255.255.252 (2 hosts)

Subnet calculations are based on IPv4 addressing. Usable host count excludes the network address and broadcast address for subnets larger than /30.

Use the IP Subnet Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

Splitting a large IP range into smaller subnets is how administrators keep a network organized, contained, and secure. With IPv4 space running thin and an estimated 29.3 billion connected devices expected by 2026, deliberate subnet planning has a direct effect on performance and on how cleanly traffic is segmented.

Boundaries here come from CIDR (Classless Inter-Domain Routing) notation paired with subnet masks, which together fix the network range, the usable host range, and the broadcast address. The mask works through bitwise operations, marking which bits of an address belong to the network and which are left for hosts.

Two addresses in every subnet are off-limits to hosts: the first is the network address and the last is the broadcast address. Overlooking that pair is a frequent slip, and because it trims two usable addresses from each subnet, leaving it out of your host count will overstate how many devices you can actually assign.

Subnetting a Class C Network for a Small Office with 50 Devices

  1. 1 Start with the network 192.168.1.0/24 and determine you need subnets for different departments, requiring at least 14 host addresses per subnet.
  2. 2 Calculate the required subnet mask: since you need 14 hosts, you need 4 host bits (2^4 = 16 addresses, minus 2 reserved = 14 usable), leaving 28 network bits (/28).
  3. 3 The subnet mask becomes 255.255.255.240, creating 16 possible subnets (2^4) with 14 usable host addresses each.
  4. 4 First subnet: 192.168.1.0/28 with usable host range 192.168.1.1 to 192.168.1.14, providing adequate addressing for your 50-device office across multiple subnets.

Source: IETF · Last updated: April 2026

Frequently Asked Questions

What is a subnet mask and what does it do?
A subnet mask divides an IP address into network and host portions. It determines which part of an IP identifies the network and which identifies individual devices. For example, 255.255.255.0 (/24) means the first 24 bits are the network and the last 8 bits are for hosts.
How many usable hosts does a /24 subnet have?
A /24 subnet (255.255.255.0) has 256 total addresses but only 254 usable host addresses. One address is reserved for the network address and one for the broadcast address.
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation uses a slash followed by the number of network bits. /24 means 24 network bits and 8 host bits (256 addresses). /16 means 65,536 addresses. Each additional bit halves the number of addresses.