IP Subnet Calculator

LOCAL · Browser-Only

Calculate IP subnet details, network ranges, and CIDR notation

IP Address

Prefix Length

Subnet Mask

Show binary

Network Address

192.168.1.0

Broadcast Address

192.168.1.255

Subnet Mask

255.255.255.0

Wildcard Mask

0.0.0.255

CIDR Notation

192.168.1.0/24

Usable Host Range

192.168.1.1 - 192.168.1.254

First Usable Host

192.168.1.1

Last Usable Host

192.168.1.254

Total Addresses

256

Usable Hosts

254

IP Class

C

IP (Hex)

0xC0A80164

IP (Binary)

11000000.10101000.00000001.01100100

Split into two /25 subnets

Dividing 192.168.1.0/24 one prefix deeper.

Common Subnet Masks

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What is IP Subnet Calculator?

Free online IP subnet calculator to calculate IP subnet information from any IP address and subnet mask or CIDR notation.

Get detailed results including network address, broadcast address, first and last usable host, total number of hosts, wildcard mask, and binary representations. Convert CIDR to a subnet mask, find how many hosts a /24 or /26 holds, or work out the IP range for a given prefix. Useful for VLSM planning, splitting a network into smaller subnets, and sizing a block to a host count. Supports IPv4 and CIDR notation input. All calculations run in your browser - fast, private, and free. No signup required.

How to Use IP Subnet Calculator

1Enter an IP address and subnet mask, or use CIDR notation (e.g., 192.168.1.0/24)
2View the calculated network address, broadcast address, and usable host range
3Check the total number of hosts, wildcard mask, and binary representations
4Adjust the subnet mask or CIDR prefix to plan your network address allocation

Frequently Asked Questions

What is a subnet?

A subnet (subnetwork) is a logical subdivision of an IP network. Subnetting divides a larger network into smaller, more manageable segments. Each subnet has its own range of IP addresses, a network address, and a broadcast address. Subnetting improves network performance, security, and address management.

What is CIDR notation?

CIDR (Classless Inter-Domain Routing) notation combines an IP address with a prefix length separated by a slash. For example, 192.168.1.0/24 means the first 24 bits are the network portion, leaving 8 bits for host addresses (254 usable hosts). CIDR replaced the older classful addressing system.

How do I determine the right subnet mask?

Choose a subnet mask based on how many hosts you need. A /24 gives 254 hosts, /25 gives 126, /26 gives 62, and so on. Enter different CIDR values in the calculator to see the number of available hosts and find the best fit for your network requirements.

What is the difference between network and broadcast addresses?

The network address is the first address in a subnet (all host bits set to 0) and identifies the subnet itself. The broadcast address is the last address (all host bits set to 1) and is used to send data to all hosts on the subnet. Neither can be assigned to individual hosts.

How many usable hosts are in a /24 versus a /26?

A /24 has 256 total addresses with 254 usable hosts, because the network and broadcast addresses are reserved. A /26 has 64 total addresses with 62 usable hosts. The formula is 2 to the power of the host bits, minus 2 for the network and broadcast addresses.

How do I convert CIDR to a subnet mask?

Enter the IP with the CIDR prefix, for example 10.0.0.0/22, and the calculator shows the equivalent dotted-decimal subnet mask (255.255.252.0 for a /22) along with the wildcard mask. The prefix length is simply the count of leading 1 bits in the mask.

What CIDR block fits a specific number of hosts?

Pick the smallest prefix whose usable host count meets your need. For 50 hosts you need at least a /26 (62 usable). For 10 hosts a /28 (14 usable) works. Try a few prefixes in the calculator and read the usable host total to find the tightest fit.

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Keep reading: Docker Cheat Sheet and ipv4 subnets reference. Doing this in code instead? See the JSON and data endpoints.

What is IP Subnet Calculator?

Free online IP subnet calculator to calculate IP subnet information from any IP address and subnet mask or CIDR notation.

How to Use IP Subnet Calculator

1Enter an IP address and subnet mask, or use CIDR notation (e.g., 192.168.1.0/24)