ip
ipku.in

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)10.2.104.0/21
network10.2.104.0/21
broadcast10.2.111.255
first host10.2.104.1
last host10.2.111.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.2.104.0/21
address00001010.00000010.01101000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000010.01101000.00000000
broadcast00001010.00000010.01101111.11111111
green = network part, grey = host part
hex0x0a026800
decimal167929856
reverse dns0.104.2.10.in-addr.arpa
ipv4-mapped::ffff:a02:6800

/21 split into /28 · 128 subnets

close ×
#networkhost rangebroadcast
110.2.104.0/2810.2.104.1 – 10.2.104.1410.2.104.15
210.2.104.16/2810.2.104.17 – 10.2.104.3010.2.104.31
310.2.104.32/2810.2.104.33 – 10.2.104.4610.2.104.47
410.2.104.48/2810.2.104.49 – 10.2.104.6210.2.104.63
510.2.104.64/2810.2.104.65 – 10.2.104.7810.2.104.79
610.2.104.80/2810.2.104.81 – 10.2.104.9410.2.104.95
710.2.104.96/2810.2.104.97 – 10.2.104.11010.2.104.111
810.2.104.112/2810.2.104.113 – 10.2.104.12610.2.104.127
910.2.104.128/2810.2.104.129 – 10.2.104.14210.2.104.143
1010.2.104.144/2810.2.104.145 – 10.2.104.15810.2.104.159
1110.2.104.160/2810.2.104.161 – 10.2.104.17410.2.104.175
1210.2.104.176/2810.2.104.177 – 10.2.104.19010.2.104.191
1310.2.104.192/2810.2.104.193 – 10.2.104.20610.2.104.207
1410.2.104.208/2810.2.104.209 – 10.2.104.22210.2.104.223
1510.2.104.224/2810.2.104.225 – 10.2.104.23810.2.104.239
1610.2.104.240/2810.2.104.241 – 10.2.104.25410.2.104.255
1710.2.105.0/2810.2.105.1 – 10.2.105.1410.2.105.15
1810.2.105.16/2810.2.105.17 – 10.2.105.3010.2.105.31
1910.2.105.32/2810.2.105.33 – 10.2.105.4610.2.105.47
2010.2.105.48/2810.2.105.49 – 10.2.105.6210.2.105.63
2110.2.105.64/2810.2.105.65 – 10.2.105.7810.2.105.79
2210.2.105.80/2810.2.105.81 – 10.2.105.9410.2.105.95
2310.2.105.96/2810.2.105.97 – 10.2.105.11010.2.105.111
2410.2.105.112/2810.2.105.113 – 10.2.105.12610.2.105.127
2510.2.105.128/2810.2.105.129 – 10.2.105.14210.2.105.143
2610.2.105.144/2810.2.105.145 – 10.2.105.15810.2.105.159
2710.2.105.160/2810.2.105.161 – 10.2.105.17410.2.105.175
2810.2.105.176/2810.2.105.177 – 10.2.105.19010.2.105.191
2910.2.105.192/2810.2.105.193 – 10.2.105.20610.2.105.207
3010.2.105.208/2810.2.105.209 – 10.2.105.22210.2.105.223
3110.2.105.224/2810.2.105.225 – 10.2.105.23810.2.105.239
3210.2.105.240/2810.2.105.241 – 10.2.105.25410.2.105.255
3310.2.106.0/2810.2.106.1 – 10.2.106.1410.2.106.15
3410.2.106.16/2810.2.106.17 – 10.2.106.3010.2.106.31
3510.2.106.32/2810.2.106.33 – 10.2.106.4610.2.106.47
3610.2.106.48/2810.2.106.49 – 10.2.106.6210.2.106.63
3710.2.106.64/2810.2.106.65 – 10.2.106.7810.2.106.79
3810.2.106.80/2810.2.106.81 – 10.2.106.9410.2.106.95
3910.2.106.96/2810.2.106.97 – 10.2.106.11010.2.106.111
4010.2.106.112/2810.2.106.113 – 10.2.106.12610.2.106.127
4110.2.106.128/2810.2.106.129 – 10.2.106.14210.2.106.143
4210.2.106.144/2810.2.106.145 – 10.2.106.15810.2.106.159
4310.2.106.160/2810.2.106.161 – 10.2.106.17410.2.106.175
4410.2.106.176/2810.2.106.177 – 10.2.106.19010.2.106.191
4510.2.106.192/2810.2.106.193 – 10.2.106.20610.2.106.207
4610.2.106.208/2810.2.106.209 – 10.2.106.22210.2.106.223
4710.2.106.224/2810.2.106.225 – 10.2.106.23810.2.106.239
4810.2.106.240/2810.2.106.241 – 10.2.106.25410.2.106.255
4910.2.107.0/2810.2.107.1 – 10.2.107.1410.2.107.15
5010.2.107.16/2810.2.107.17 – 10.2.107.3010.2.107.31
5110.2.107.32/2810.2.107.33 – 10.2.107.4610.2.107.47
5210.2.107.48/2810.2.107.49 – 10.2.107.6210.2.107.63
5310.2.107.64/2810.2.107.65 – 10.2.107.7810.2.107.79
5410.2.107.80/2810.2.107.81 – 10.2.107.9410.2.107.95
5510.2.107.96/2810.2.107.97 – 10.2.107.11010.2.107.111
5610.2.107.112/2810.2.107.113 – 10.2.107.12610.2.107.127
5710.2.107.128/2810.2.107.129 – 10.2.107.14210.2.107.143
5810.2.107.144/2810.2.107.145 – 10.2.107.15810.2.107.159
5910.2.107.160/2810.2.107.161 – 10.2.107.17410.2.107.175
6010.2.107.176/2810.2.107.177 – 10.2.107.19010.2.107.191
6110.2.107.192/2810.2.107.193 – 10.2.107.20610.2.107.207
6210.2.107.208/2810.2.107.209 – 10.2.107.22210.2.107.223
6310.2.107.224/2810.2.107.225 – 10.2.107.23810.2.107.239
6410.2.107.240/2810.2.107.241 – 10.2.107.25410.2.107.255
6510.2.108.0/2810.2.108.1 – 10.2.108.1410.2.108.15
6610.2.108.16/2810.2.108.17 – 10.2.108.3010.2.108.31
6710.2.108.32/2810.2.108.33 – 10.2.108.4610.2.108.47
6810.2.108.48/2810.2.108.49 – 10.2.108.6210.2.108.63
6910.2.108.64/2810.2.108.65 – 10.2.108.7810.2.108.79
7010.2.108.80/2810.2.108.81 – 10.2.108.9410.2.108.95
7110.2.108.96/2810.2.108.97 – 10.2.108.11010.2.108.111
7210.2.108.112/2810.2.108.113 – 10.2.108.12610.2.108.127
7310.2.108.128/2810.2.108.129 – 10.2.108.14210.2.108.143
7410.2.108.144/2810.2.108.145 – 10.2.108.15810.2.108.159
7510.2.108.160/2810.2.108.161 – 10.2.108.17410.2.108.175
7610.2.108.176/2810.2.108.177 – 10.2.108.19010.2.108.191
7710.2.108.192/2810.2.108.193 – 10.2.108.20610.2.108.207
7810.2.108.208/2810.2.108.209 – 10.2.108.22210.2.108.223
7910.2.108.224/2810.2.108.225 – 10.2.108.23810.2.108.239
8010.2.108.240/2810.2.108.241 – 10.2.108.25410.2.108.255
8110.2.109.0/2810.2.109.1 – 10.2.109.1410.2.109.15
8210.2.109.16/2810.2.109.17 – 10.2.109.3010.2.109.31
8310.2.109.32/2810.2.109.33 – 10.2.109.4610.2.109.47
8410.2.109.48/2810.2.109.49 – 10.2.109.6210.2.109.63
8510.2.109.64/2810.2.109.65 – 10.2.109.7810.2.109.79
8610.2.109.80/2810.2.109.81 – 10.2.109.9410.2.109.95
8710.2.109.96/2810.2.109.97 – 10.2.109.11010.2.109.111
8810.2.109.112/2810.2.109.113 – 10.2.109.12610.2.109.127
8910.2.109.128/2810.2.109.129 – 10.2.109.14210.2.109.143
9010.2.109.144/2810.2.109.145 – 10.2.109.15810.2.109.159
9110.2.109.160/2810.2.109.161 – 10.2.109.17410.2.109.175
9210.2.109.176/2810.2.109.177 – 10.2.109.19010.2.109.191
9310.2.109.192/2810.2.109.193 – 10.2.109.20610.2.109.207
9410.2.109.208/2810.2.109.209 – 10.2.109.22210.2.109.223
9510.2.109.224/2810.2.109.225 – 10.2.109.23810.2.109.239
9610.2.109.240/2810.2.109.241 – 10.2.109.25410.2.109.255
9710.2.110.0/2810.2.110.1 – 10.2.110.1410.2.110.15
9810.2.110.16/2810.2.110.17 – 10.2.110.3010.2.110.31
9910.2.110.32/2810.2.110.33 – 10.2.110.4610.2.110.47
10010.2.110.48/2810.2.110.49 – 10.2.110.6210.2.110.63
10110.2.110.64/2810.2.110.65 – 10.2.110.7810.2.110.79
10210.2.110.80/2810.2.110.81 – 10.2.110.9410.2.110.95
10310.2.110.96/2810.2.110.97 – 10.2.110.11010.2.110.111
10410.2.110.112/2810.2.110.113 – 10.2.110.12610.2.110.127
10510.2.110.128/2810.2.110.129 – 10.2.110.14210.2.110.143
10610.2.110.144/2810.2.110.145 – 10.2.110.15810.2.110.159
10710.2.110.160/2810.2.110.161 – 10.2.110.17410.2.110.175
10810.2.110.176/2810.2.110.177 – 10.2.110.19010.2.110.191
10910.2.110.192/2810.2.110.193 – 10.2.110.20610.2.110.207
11010.2.110.208/2810.2.110.209 – 10.2.110.22210.2.110.223
11110.2.110.224/2810.2.110.225 – 10.2.110.23810.2.110.239
11210.2.110.240/2810.2.110.241 – 10.2.110.25410.2.110.255
11310.2.111.0/2810.2.111.1 – 10.2.111.1410.2.111.15
11410.2.111.16/2810.2.111.17 – 10.2.111.3010.2.111.31
11510.2.111.32/2810.2.111.33 – 10.2.111.4610.2.111.47
11610.2.111.48/2810.2.111.49 – 10.2.111.6210.2.111.63
11710.2.111.64/2810.2.111.65 – 10.2.111.7810.2.111.79
11810.2.111.80/2810.2.111.81 – 10.2.111.9410.2.111.95
11910.2.111.96/2810.2.111.97 – 10.2.111.11010.2.111.111
12010.2.111.112/2810.2.111.113 – 10.2.111.12610.2.111.127
12110.2.111.128/2810.2.111.129 – 10.2.111.14210.2.111.143
12210.2.111.144/2810.2.111.145 – 10.2.111.15810.2.111.159
12310.2.111.160/2810.2.111.161 – 10.2.111.17410.2.111.175
12410.2.111.176/2810.2.111.177 – 10.2.111.19010.2.111.191
12510.2.111.192/2810.2.111.193 – 10.2.111.20610.2.111.207
12610.2.111.208/2810.2.111.209 – 10.2.111.22210.2.111.223
12710.2.111.224/2810.2.111.225 – 10.2.111.23810.2.111.239
12810.2.111.240/2810.2.111.241 – 10.2.111.25410.2.111.255
01 / table

IPv4 CIDR prefix table.

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

prefixsubnet maskaddresseshostsin your /21
/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-
/18255.255.192.016,38416,382-
/19255.255.224.08,1928,190-
/20255.255.240.04,0964,094-
/21255.255.248.02,0482,0461
/22255.255.252.01,0241,0222 split →
/23255.255.254.05125104 split →
/24255.255.255.02562548 split →
/25255.255.255.12812812616 split →
/26255.255.255.192646232 split →
/27255.255.255.224323064 split →
/28255.255.255.2401614128 split →
/29255.255.255.24886256 split →
/30255.255.255.25242512 split →
/31255.255.255.254221,024 split →
/32255.255.255.255112,048 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 →