IPv4 Subnet Calculator

Updated · by the 19216811ip team

On this page
  1. How to use the subnet calculator
  2. What the results mean
  3. Home network example
  4. CIDR to subnet mask cheat sheet
  5. Private IP ranges
  6. Frequently asked questions

Type an IPv4 address and choose a prefix length (CIDR) or subnet mask. The calculator shows the network and broadcast address, the usable host range and how many devices fit.

IP address192.168.1.1
Network address192.168.1.0/24
Subnet mask255.255.255.0
Wildcard mask0.0.0.255
Broadcast address192.168.1.255
First usable host192.168.1.1
Last usable host192.168.1.254
Usable hosts254
Total addresses256
IP classC
Address typePrivate (RFC 1918)
Binary mask11111111.11111111.11111111.00000000

How to use the subnet calculator

  1. Enter any IPv4 address, such as your router’s 192.168.1.1.
  2. Pick the prefix. Home networks almost always use /24 (255.255.255.0).
  3. Read the results. They update as you type.

What the results mean

  • Network address — the first address in the subnet. It identifies the network and is not given to a device.
  • Broadcast address — the last address. Messages sent here reach every device on the subnet.
  • Usable host range — addresses you can give to routers, phones, printers and so on.
  • Subnet mask — marks which part of the address is the network (the 255s) and which part is the host.
  • Wildcard mask — the mask inverted, used in router access lists and OSPF.

Home network example

A router at 192.168.1.1 with mask 255.255.255.0 (/24) owns 192.168.1.0 – 192.168.1.255. Devices can use 192.168.1.1 – 192.168.1.254, so up to 254 of them fit. The router usually gives them addresses from a smaller pool, such as 192.168.1.100 – 192.168.1.199.

CIDR to subnet mask cheat sheet

CIDRSubnet maskWildcardUsable hosts
/32255.255.255.2550.0.0.01
/31255.255.255.2540.0.0.12
/30255.255.255.2520.0.0.32
/29255.255.255.2480.0.0.76
/28255.255.255.2400.0.0.1514
/27255.255.255.2240.0.0.3130
/26255.255.255.1920.0.0.6362
/25255.255.255.1280.0.0.127126
/24255.255.255.00.0.0.255254
/23255.255.254.00.0.1.255510
/22255.255.252.00.0.3.2551,022
/21255.255.248.00.0.7.2552,046
/20255.255.240.00.0.15.2554,094
/19255.255.224.00.0.31.2558,190
/18255.255.192.00.0.63.25516,382
/17255.255.128.00.0.127.25532,766
/16255.255.0.00.0.255.25565,534
/12255.240.0.00.15.255.2551,048,574
/8255.0.0.00.255.255.25516,777,214

Private IP ranges

RangeCIDRTypical use
10.0.0.0 – 10.255.255.25510.0.0.0/8Large networks, Xfinity 10.0.0.1
172.16.0.0 – 172.31.255.255172.16.0.0/12Offices, Docker, VPNs
192.168.0.0 – 192.168.255.255192.168.0.0/16Home routers (192.168.1.1, 192.168.0.1)

Frequently asked questions

What subnet mask does my home network use?

Almost every home router uses 255.255.255.0, which is /24. It allows 254 devices.

How many hosts are in a /24?

A /24 has 256 addresses. Two are reserved (network and broadcast), so 254 are usable.

What is the difference between /24 and 255.255.255.0?

Nothing. They are two ways of writing the same mask: /24 means the first 24 bits are the network part.

Why do /31 and /32 show no broadcast?

/32 is a single address. /31 is used for point-to-point links (RFC 3021), where both addresses are usable.