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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)10.20.0.0/16
network10.20.0.0/16
broadcast10.20.255.255
first host10.20.0.1
last host10.20.255.254
subnet mask255.255.0.0
wildcard0.0.255.255
addresses65,536
usable hosts65,534
classA
ipcalc 10.20.0.0/16
address00001010.00010100.00000000.00000000
subnet mask11111111.11111111.00000000.00000000
network00001010.00010100.00000000.00000000
broadcast00001010.00010100.11111111.11111111
green = network part, grey = host part
hex0x0a140000
decimal169082880
reverse dns0.0.20.10.in-addr.arpa
ipv4-mapped::ffff:a14:0

/16 split into /21 · 32 subnets

close ×
#networkhost rangebroadcast
110.20.0.0/2110.20.0.1 – 10.20.7.25410.20.7.255
210.20.8.0/2110.20.8.1 – 10.20.15.25410.20.15.255
310.20.16.0/2110.20.16.1 – 10.20.23.25410.20.23.255
410.20.24.0/2110.20.24.1 – 10.20.31.25410.20.31.255
510.20.32.0/2110.20.32.1 – 10.20.39.25410.20.39.255
610.20.40.0/2110.20.40.1 – 10.20.47.25410.20.47.255
710.20.48.0/2110.20.48.1 – 10.20.55.25410.20.55.255
810.20.56.0/2110.20.56.1 – 10.20.63.25410.20.63.255
910.20.64.0/2110.20.64.1 – 10.20.71.25410.20.71.255
1010.20.72.0/2110.20.72.1 – 10.20.79.25410.20.79.255
1110.20.80.0/2110.20.80.1 – 10.20.87.25410.20.87.255
1210.20.88.0/2110.20.88.1 – 10.20.95.25410.20.95.255
1310.20.96.0/2110.20.96.1 – 10.20.103.25410.20.103.255
1410.20.104.0/2110.20.104.1 – 10.20.111.25410.20.111.255
1510.20.112.0/2110.20.112.1 – 10.20.119.25410.20.119.255
1610.20.120.0/2110.20.120.1 – 10.20.127.25410.20.127.255
1710.20.128.0/2110.20.128.1 – 10.20.135.25410.20.135.255
1810.20.136.0/2110.20.136.1 – 10.20.143.25410.20.143.255
1910.20.144.0/2110.20.144.1 – 10.20.151.25410.20.151.255
2010.20.152.0/2110.20.152.1 – 10.20.159.25410.20.159.255
2110.20.160.0/2110.20.160.1 – 10.20.167.25410.20.167.255
2210.20.168.0/2110.20.168.1 – 10.20.175.25410.20.175.255
2310.20.176.0/2110.20.176.1 – 10.20.183.25410.20.183.255
2410.20.184.0/2110.20.184.1 – 10.20.191.25410.20.191.255
2510.20.192.0/2110.20.192.1 – 10.20.199.25410.20.199.255
2610.20.200.0/2110.20.200.1 – 10.20.207.25410.20.207.255
2710.20.208.0/2110.20.208.1 – 10.20.215.25410.20.215.255
2810.20.216.0/2110.20.216.1 – 10.20.223.25410.20.223.255
2910.20.224.0/2110.20.224.1 – 10.20.231.25410.20.231.255
3010.20.232.0/2110.20.232.1 – 10.20.239.25410.20.239.255
3110.20.240.0/2110.20.240.1 – 10.20.247.25410.20.247.255
3210.20.248.0/2110.20.248.1 – 10.20.255.25410.20.255.255
01 / table

IPv4 CIDR prefix table.

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

prefixsubnet maskaddresseshostsin your /16
/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-
/16255.255.0.065,53665,5341
/17255.255.128.032,76832,7662 split →
/18255.255.192.016,38416,3824 split →
/19255.255.224.08,1928,1908 split →
/20255.255.240.04,0964,09416 split →
/21255.255.248.02,0482,04632 split →
/22255.255.252.01,0241,02264 split →
/23255.255.254.0512510128 split →
/24255.255.255.0256254256 split →
/25255.255.255.128128126512 split →
/26255.255.255.19264621,024 split →
/27255.255.255.22432302,048 split →
/28255.255.255.24016144,096 split →
/29255.255.255.248868,192 split →
/30255.255.255.2524216,384 split →
/31255.255.255.2542232,768 split →
/32255.255.255.2551165,536 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 →