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IP Subnet Calculator

Calculate IPv4 and IPv6 subnet information including network address, usable host range, broadcast address, subnet mask, wildcard mask, CIDR notation, and more. Also lists all possible subnets for a given prefix.

IPv4IPv6CIDRSubnet MaskNetwork AddressHost Range
How to use this calculator
Select a Network Class and Subnet mask, then enter an IP address. Click Calculate to see full subnet details and all possible networks for that prefix. For IPv6, select a Prefix Length and enter an IPv6 address.

IPv4 Subnet Calculator

IPv4 Subnet Calculator

Enter IP address and subnet mask

IPv6 Subnet Calculator

IPv6 Subnet Calculator

Enter IPv6 address and prefix length

About IP Subnetting

A subnet is a logical subdivision of an IP network. Subnetting divides a large network into smaller, more manageable segments, improving performance and security. The process is governed by a subnet mask (IPv4) or prefix length (IPv6), which determines which portion of an IP address identifies the network and which identifies the host.

CIDR (Classless Inter-Domain Routing) notation expresses both the IP address and its associated routing prefix — 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).

IPv4 addresses are 32-bit numbers divided into four octets. IPv6 addresses are 128-bit numbers, providing a vastly larger address space (approximately 3.4 × 10³⁸ addresses) to accommodate the growing number of internet-connected devices.

IPv4 Subnet Reference Table

Prefix SizeNetwork MaskUsable Hosts / Subnet
/1128.0.0.02,147,483,646
/2192.0.0.01,073,741,822
/3224.0.0.0536,870,910
/4240.0.0.0268,435,454
/5248.0.0.0134,217,726
/6252.0.0.067,108,862
/7254.0.0.033,554,430
Class A
/8255.0.0.016,777,214
/9255.128.0.08,388,606
/10255.192.0.04,194,302
/11255.224.0.02,097,150
/12255.240.0.01,048,574
/13255.248.0.0524,286
/14255.252.0.0262,142
/15255.254.0.0131,070
Class B
/16255.255.0.065,534
/17255.255.128.032,766
/18255.255.192.016,382
/19255.255.224.08,190
/20255.255.240.04,094
/21255.255.248.02,046
/22255.255.252.01,022
/23255.255.254.0510
Class C
/24255.255.255.0254
/25255.255.255.128126
/26255.255.255.19262
/27255.255.255.22430
/28255.255.255.24014
/29255.255.255.2486
/30255.255.255.2522
/31255.255.255.2540
/32255.255.255.2550
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Quick Reference

  • • /24 = 254 usable hosts (Class C)
  • • /16 = 65,534 usable hosts (Class B)
  • • /8 = 16,777,214 usable hosts (Class A)
  • • /32 = single host (no subnet)
  • • /30 = 2 usable hosts (point-to-point)
  • • Private: 10.x, 172.16–31.x, 192.168.x
  • • Loopback: 127.0.0.1

Common Subnets

/24255.255.255.0254 hosts
/25255.255.255.128126 hosts
/26255.255.255.19262 hosts
/27255.255.255.22430 hosts
/28255.255.255.24014 hosts
/29255.255.255.2486 hosts
/30255.255.255.2522 hosts

Frequently Asked Questions

Subnetting divides a large IP network into smaller, more manageable subnetworks. Benefits include: improved security (isolating network segments), reduced broadcast traffic, more efficient IP address allocation, and easier network management and troubleshooting.