IP Subnet Calculator

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

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

An IP Subnet Calculator helps network administrators divide IP address ranges into smaller, manageable subnets for efficient network organization. With IPv4 addresses becoming increasingly scarce and the projected 29.3 billion connected devices by 2026, proper subnet planning is crucial for optimal network performance and security.

The calculator uses CIDR (Classless Inter-Domain Routing) notation and subnet masks to determine network boundaries, host ranges, and broadcast addresses. It applies bitwise operations where the subnet mask defines which bits represent the network portion versus the host portion of an IP address.

Remember that the first IP in each subnet is the network address and the last is the broadcast address, both unusable for hosts. A common mistake is forgetting to account for these reserved addresses when calculating available host IPs, which reduces your usable addresses by 2 per subnet.

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.