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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)10.21.64.0/18
network10.21.64.0/18
broadcast10.21.127.255
first host10.21.64.1
last host10.21.127.254
subnet mask255.255.192.0
wildcard0.0.63.255
addresses16,384
usable hosts16,382
classA
ipcalc 10.21.64.0/18
address00001010.00010101.01000000.00000000
subnet mask11111111.11111111.11000000.00000000
network00001010.00010101.01000000.00000000
broadcast00001010.00010101.01111111.11111111
green = network part, grey = host part
hex0x0a154000
decimal169164800
reverse dns0.64.21.10.in-addr.arpa
ipv4-mapped::ffff:a15:4000

/18 split into /24 · 64 subnets

close ×
#networkhost rangebroadcast
110.21.64.0/2410.21.64.1 – 10.21.64.25410.21.64.255
210.21.65.0/2410.21.65.1 – 10.21.65.25410.21.65.255
310.21.66.0/2410.21.66.1 – 10.21.66.25410.21.66.255
410.21.67.0/2410.21.67.1 – 10.21.67.25410.21.67.255
510.21.68.0/2410.21.68.1 – 10.21.68.25410.21.68.255
610.21.69.0/2410.21.69.1 – 10.21.69.25410.21.69.255
710.21.70.0/2410.21.70.1 – 10.21.70.25410.21.70.255
810.21.71.0/2410.21.71.1 – 10.21.71.25410.21.71.255
910.21.72.0/2410.21.72.1 – 10.21.72.25410.21.72.255
1010.21.73.0/2410.21.73.1 – 10.21.73.25410.21.73.255
1110.21.74.0/2410.21.74.1 – 10.21.74.25410.21.74.255
1210.21.75.0/2410.21.75.1 – 10.21.75.25410.21.75.255
1310.21.76.0/2410.21.76.1 – 10.21.76.25410.21.76.255
1410.21.77.0/2410.21.77.1 – 10.21.77.25410.21.77.255
1510.21.78.0/2410.21.78.1 – 10.21.78.25410.21.78.255
1610.21.79.0/2410.21.79.1 – 10.21.79.25410.21.79.255
1710.21.80.0/2410.21.80.1 – 10.21.80.25410.21.80.255
1810.21.81.0/2410.21.81.1 – 10.21.81.25410.21.81.255
1910.21.82.0/2410.21.82.1 – 10.21.82.25410.21.82.255
2010.21.83.0/2410.21.83.1 – 10.21.83.25410.21.83.255
2110.21.84.0/2410.21.84.1 – 10.21.84.25410.21.84.255
2210.21.85.0/2410.21.85.1 – 10.21.85.25410.21.85.255
2310.21.86.0/2410.21.86.1 – 10.21.86.25410.21.86.255
2410.21.87.0/2410.21.87.1 – 10.21.87.25410.21.87.255
2510.21.88.0/2410.21.88.1 – 10.21.88.25410.21.88.255
2610.21.89.0/2410.21.89.1 – 10.21.89.25410.21.89.255
2710.21.90.0/2410.21.90.1 – 10.21.90.25410.21.90.255
2810.21.91.0/2410.21.91.1 – 10.21.91.25410.21.91.255
2910.21.92.0/2410.21.92.1 – 10.21.92.25410.21.92.255
3010.21.93.0/2410.21.93.1 – 10.21.93.25410.21.93.255
3110.21.94.0/2410.21.94.1 – 10.21.94.25410.21.94.255
3210.21.95.0/2410.21.95.1 – 10.21.95.25410.21.95.255
3310.21.96.0/2410.21.96.1 – 10.21.96.25410.21.96.255
3410.21.97.0/2410.21.97.1 – 10.21.97.25410.21.97.255
3510.21.98.0/2410.21.98.1 – 10.21.98.25410.21.98.255
3610.21.99.0/2410.21.99.1 – 10.21.99.25410.21.99.255
3710.21.100.0/2410.21.100.1 – 10.21.100.25410.21.100.255
3810.21.101.0/2410.21.101.1 – 10.21.101.25410.21.101.255
3910.21.102.0/2410.21.102.1 – 10.21.102.25410.21.102.255
4010.21.103.0/2410.21.103.1 – 10.21.103.25410.21.103.255
4110.21.104.0/2410.21.104.1 – 10.21.104.25410.21.104.255
4210.21.105.0/2410.21.105.1 – 10.21.105.25410.21.105.255
4310.21.106.0/2410.21.106.1 – 10.21.106.25410.21.106.255
4410.21.107.0/2410.21.107.1 – 10.21.107.25410.21.107.255
4510.21.108.0/2410.21.108.1 – 10.21.108.25410.21.108.255
4610.21.109.0/2410.21.109.1 – 10.21.109.25410.21.109.255
4710.21.110.0/2410.21.110.1 – 10.21.110.25410.21.110.255
4810.21.111.0/2410.21.111.1 – 10.21.111.25410.21.111.255
4910.21.112.0/2410.21.112.1 – 10.21.112.25410.21.112.255
5010.21.113.0/2410.21.113.1 – 10.21.113.25410.21.113.255
5110.21.114.0/2410.21.114.1 – 10.21.114.25410.21.114.255
5210.21.115.0/2410.21.115.1 – 10.21.115.25410.21.115.255
5310.21.116.0/2410.21.116.1 – 10.21.116.25410.21.116.255
5410.21.117.0/2410.21.117.1 – 10.21.117.25410.21.117.255
5510.21.118.0/2410.21.118.1 – 10.21.118.25410.21.118.255
5610.21.119.0/2410.21.119.1 – 10.21.119.25410.21.119.255
5710.21.120.0/2410.21.120.1 – 10.21.120.25410.21.120.255
5810.21.121.0/2410.21.121.1 – 10.21.121.25410.21.121.255
5910.21.122.0/2410.21.122.1 – 10.21.122.25410.21.122.255
6010.21.123.0/2410.21.123.1 – 10.21.123.25410.21.123.255
6110.21.124.0/2410.21.124.1 – 10.21.124.25410.21.124.255
6210.21.125.0/2410.21.125.1 – 10.21.125.25410.21.125.255
6310.21.126.0/2410.21.126.1 – 10.21.126.25410.21.126.255
6410.21.127.0/2410.21.127.1 – 10.21.127.25410.21.127.255
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 →