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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)10.20.128.0/18
network10.20.128.0/18
broadcast10.20.191.255
first host10.20.128.1
last host10.20.191.254
subnet mask255.255.192.0
wildcard0.0.63.255
addresses16,384
usable hosts16,382
classA
ipcalc 10.20.128.0/18
address00001010.00010100.10000000.00000000
subnet mask11111111.11111111.11000000.00000000
network00001010.00010100.10000000.00000000
broadcast00001010.00010100.10111111.11111111
green = network part, grey = host part
hex0x0a148000
decimal169115648
reverse dns0.128.20.10.in-addr.arpa
ipv4-mapped::ffff:a14:8000

/18 split into /23 · 32 subnets

close ×
#networkhost rangebroadcast
110.20.128.0/2310.20.128.1 – 10.20.129.25410.20.129.255
210.20.130.0/2310.20.130.1 – 10.20.131.25410.20.131.255
310.20.132.0/2310.20.132.1 – 10.20.133.25410.20.133.255
410.20.134.0/2310.20.134.1 – 10.20.135.25410.20.135.255
510.20.136.0/2310.20.136.1 – 10.20.137.25410.20.137.255
610.20.138.0/2310.20.138.1 – 10.20.139.25410.20.139.255
710.20.140.0/2310.20.140.1 – 10.20.141.25410.20.141.255
810.20.142.0/2310.20.142.1 – 10.20.143.25410.20.143.255
910.20.144.0/2310.20.144.1 – 10.20.145.25410.20.145.255
1010.20.146.0/2310.20.146.1 – 10.20.147.25410.20.147.255
1110.20.148.0/2310.20.148.1 – 10.20.149.25410.20.149.255
1210.20.150.0/2310.20.150.1 – 10.20.151.25410.20.151.255
1310.20.152.0/2310.20.152.1 – 10.20.153.25410.20.153.255
1410.20.154.0/2310.20.154.1 – 10.20.155.25410.20.155.255
1510.20.156.0/2310.20.156.1 – 10.20.157.25410.20.157.255
1610.20.158.0/2310.20.158.1 – 10.20.159.25410.20.159.255
1710.20.160.0/2310.20.160.1 – 10.20.161.25410.20.161.255
1810.20.162.0/2310.20.162.1 – 10.20.163.25410.20.163.255
1910.20.164.0/2310.20.164.1 – 10.20.165.25410.20.165.255
2010.20.166.0/2310.20.166.1 – 10.20.167.25410.20.167.255
2110.20.168.0/2310.20.168.1 – 10.20.169.25410.20.169.255
2210.20.170.0/2310.20.170.1 – 10.20.171.25410.20.171.255
2310.20.172.0/2310.20.172.1 – 10.20.173.25410.20.173.255
2410.20.174.0/2310.20.174.1 – 10.20.175.25410.20.175.255
2510.20.176.0/2310.20.176.1 – 10.20.177.25410.20.177.255
2610.20.178.0/2310.20.178.1 – 10.20.179.25410.20.179.255
2710.20.180.0/2310.20.180.1 – 10.20.181.25410.20.181.255
2810.20.182.0/2310.20.182.1 – 10.20.183.25410.20.183.255
2910.20.184.0/2310.20.184.1 – 10.20.185.25410.20.185.255
3010.20.186.0/2310.20.186.1 – 10.20.187.25410.20.187.255
3110.20.188.0/2310.20.188.1 – 10.20.189.25410.20.189.255
3210.20.190.0/2310.20.190.1 – 10.20.191.25410.20.191.255
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 →