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IPv4 Subnet Calculator

Enter an IP with a CIDR prefix or a subnet mask to see its network, broadcast, host range, and host count. You can also split the network into smaller subnets.

$ ipcalc
Try:192.168.1.10/2410.0.0.0/8172.16.5.4/20203.0.113.9/29
IPv6 calculator →
private IP (RFC 1918)10.21.192.0/18
network10.21.192.0/18
broadcast10.21.255.255
first host10.21.192.1
last host10.21.255.254
subnet mask255.255.192.0
wildcard0.0.63.255
addresses16,384
usable hosts16,382
classA
ipcalc 10.21.192.0/18
address00001010.00010101.11000000.00000000
subnet mask11111111.11111111.11000000.00000000
network00001010.00010101.11000000.00000000
broadcast00001010.00010101.11111111.11111111
green = network part, grey = host part
hex0x0a15c000
decimal169197568
reverse dns0.192.21.10.in-addr.arpa
ipv4-mapped::ffff:a15:c000

/18 split into /24 · 64 subnets

close ×
#networkhost rangebroadcast
110.21.192.0/2410.21.192.1 – 10.21.192.25410.21.192.255
210.21.193.0/2410.21.193.1 – 10.21.193.25410.21.193.255
310.21.194.0/2410.21.194.1 – 10.21.194.25410.21.194.255
410.21.195.0/2410.21.195.1 – 10.21.195.25410.21.195.255
510.21.196.0/2410.21.196.1 – 10.21.196.25410.21.196.255
610.21.197.0/2410.21.197.1 – 10.21.197.25410.21.197.255
710.21.198.0/2410.21.198.1 – 10.21.198.25410.21.198.255
810.21.199.0/2410.21.199.1 – 10.21.199.25410.21.199.255
910.21.200.0/2410.21.200.1 – 10.21.200.25410.21.200.255
1010.21.201.0/2410.21.201.1 – 10.21.201.25410.21.201.255
1110.21.202.0/2410.21.202.1 – 10.21.202.25410.21.202.255
1210.21.203.0/2410.21.203.1 – 10.21.203.25410.21.203.255
1310.21.204.0/2410.21.204.1 – 10.21.204.25410.21.204.255
1410.21.205.0/2410.21.205.1 – 10.21.205.25410.21.205.255
1510.21.206.0/2410.21.206.1 – 10.21.206.25410.21.206.255
1610.21.207.0/2410.21.207.1 – 10.21.207.25410.21.207.255
1710.21.208.0/2410.21.208.1 – 10.21.208.25410.21.208.255
1810.21.209.0/2410.21.209.1 – 10.21.209.25410.21.209.255
1910.21.210.0/2410.21.210.1 – 10.21.210.25410.21.210.255
2010.21.211.0/2410.21.211.1 – 10.21.211.25410.21.211.255
2110.21.212.0/2410.21.212.1 – 10.21.212.25410.21.212.255
2210.21.213.0/2410.21.213.1 – 10.21.213.25410.21.213.255
2310.21.214.0/2410.21.214.1 – 10.21.214.25410.21.214.255
2410.21.215.0/2410.21.215.1 – 10.21.215.25410.21.215.255
2510.21.216.0/2410.21.216.1 – 10.21.216.25410.21.216.255
2610.21.217.0/2410.21.217.1 – 10.21.217.25410.21.217.255
2710.21.218.0/2410.21.218.1 – 10.21.218.25410.21.218.255
2810.21.219.0/2410.21.219.1 – 10.21.219.25410.21.219.255
2910.21.220.0/2410.21.220.1 – 10.21.220.25410.21.220.255
3010.21.221.0/2410.21.221.1 – 10.21.221.25410.21.221.255
3110.21.222.0/2410.21.222.1 – 10.21.222.25410.21.222.255
3210.21.223.0/2410.21.223.1 – 10.21.223.25410.21.223.255
3310.21.224.0/2410.21.224.1 – 10.21.224.25410.21.224.255
3410.21.225.0/2410.21.225.1 – 10.21.225.25410.21.225.255
3510.21.226.0/2410.21.226.1 – 10.21.226.25410.21.226.255
3610.21.227.0/2410.21.227.1 – 10.21.227.25410.21.227.255
3710.21.228.0/2410.21.228.1 – 10.21.228.25410.21.228.255
3810.21.229.0/2410.21.229.1 – 10.21.229.25410.21.229.255
3910.21.230.0/2410.21.230.1 – 10.21.230.25410.21.230.255
4010.21.231.0/2410.21.231.1 – 10.21.231.25410.21.231.255
4110.21.232.0/2410.21.232.1 – 10.21.232.25410.21.232.255
4210.21.233.0/2410.21.233.1 – 10.21.233.25410.21.233.255
4310.21.234.0/2410.21.234.1 – 10.21.234.25410.21.234.255
4410.21.235.0/2410.21.235.1 – 10.21.235.25410.21.235.255
4510.21.236.0/2410.21.236.1 – 10.21.236.25410.21.236.255
4610.21.237.0/2410.21.237.1 – 10.21.237.25410.21.237.255
4710.21.238.0/2410.21.238.1 – 10.21.238.25410.21.238.255
4810.21.239.0/2410.21.239.1 – 10.21.239.25410.21.239.255
4910.21.240.0/2410.21.240.1 – 10.21.240.25410.21.240.255
5010.21.241.0/2410.21.241.1 – 10.21.241.25410.21.241.255
5110.21.242.0/2410.21.242.1 – 10.21.242.25410.21.242.255
5210.21.243.0/2410.21.243.1 – 10.21.243.25410.21.243.255
5310.21.244.0/2410.21.244.1 – 10.21.244.25410.21.244.255
5410.21.245.0/2410.21.245.1 – 10.21.245.25410.21.245.255
5510.21.246.0/2410.21.246.1 – 10.21.246.25410.21.246.255
5610.21.247.0/2410.21.247.1 – 10.21.247.25410.21.247.255
5710.21.248.0/2410.21.248.1 – 10.21.248.25410.21.248.255
5810.21.249.0/2410.21.249.1 – 10.21.249.25410.21.249.255
5910.21.250.0/2410.21.250.1 – 10.21.250.25410.21.250.255
6010.21.251.0/2410.21.251.1 – 10.21.251.25410.21.251.255
6110.21.252.0/2410.21.252.1 – 10.21.252.25410.21.252.255
6210.21.253.0/2410.21.253.1 – 10.21.253.25410.21.253.255
6310.21.254.0/2410.21.254.1 – 10.21.254.25410.21.254.255
6410.21.255.0/2410.21.255.1 – 10.21.255.25410.21.255.255
01 / table

IPv4 CIDR prefix table.

Click a prefix longer than your network to split it into subnets.

prefixsubnet maskaddresseshostsin your /18
/00.0.0.04,294,967,2964,294,967,294-
/1128.0.0.02,147,483,6482,147,483,646-
/2192.0.0.01,073,741,8241,073,741,822-
/3224.0.0.0536,870,912536,870,910-
/4240.0.0.0268,435,456268,435,454-
/5248.0.0.0134,217,728134,217,726-
/6252.0.0.067,108,86467,108,862-
/7254.0.0.033,554,43233,554,430-
/8255.0.0.016,777,21616,777,214-
/9255.128.0.08,388,6088,388,606-
/10255.192.0.04,194,3044,194,302-
/11255.224.0.02,097,1522,097,150-
/12255.240.0.01,048,5761,048,574-
/13255.248.0.0524,288524,286-
/14255.252.0.0262,144262,142-
/15255.254.0.0131,072131,070-
/16255.255.0.065,53665,534-
/17255.255.128.032,76832,766-
/18255.255.192.016,38416,3821
/19255.255.224.08,1928,1902 split →
/20255.255.240.04,0964,0944 split →
/21255.255.248.02,0482,0468 split →
/22255.255.252.01,0241,02216 split →
/23255.255.254.051251032 split →
/24255.255.255.025625464 split →
/25255.255.255.128128126128 split →
/26255.255.255.1926462256 split →
/27255.255.255.2243230512 split →
/28255.255.255.24016141,024 split →
/29255.255.255.248862,048 split →
/30255.255.255.252424,096 split →
/31255.255.255.254228,192 split →
/32255.255.255.2551116,384 split →
02 / faq

About this calculator.

How do I use this subnet calculator?

▼

Type an IP address followed by a prefix, like 192.168.1.10/24, or by a subnet mask, like 192.168.1.10 255.255.255.0. Without a prefix it uses /24. Click a row in the table to split the network into smaller subnets.

Why are usable hosts always 2 fewer?

▼

The first address in a subnet is the network address and the last is the broadcast address, so neither can go to a device. The exceptions are /31 (point-to-point links, RFC 3021) and /32 (a single address), which use every address.

Can I use it from a terminal?

▼

Yes. curl 'ipku.in/en/tools/ipv4-subnet-calculator?q=192.168.1.10/24' returns the result as plain text.

Learn how to work it out →