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)10.2.0.0/21
network10.2.0.0/21
broadcast10.2.7.255
first host10.2.0.1
last host10.2.7.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.2.0.0/21
address00001010.00000010.00000000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000010.00000000.00000000
broadcast00001010.00000010.00000111.11111111
green = network part, grey = host part
hex0x0a020000
decimal167903232
reverse dns0.0.2.10.in-addr.arpa
ipv4-mapped::ffff:a02:0

/21 split into /28 · 128 subnets

close ×
#networkhost rangebroadcast
110.2.0.0/2810.2.0.1 – 10.2.0.1410.2.0.15
210.2.0.16/2810.2.0.17 – 10.2.0.3010.2.0.31
310.2.0.32/2810.2.0.33 – 10.2.0.4610.2.0.47
410.2.0.48/2810.2.0.49 – 10.2.0.6210.2.0.63
510.2.0.64/2810.2.0.65 – 10.2.0.7810.2.0.79
610.2.0.80/2810.2.0.81 – 10.2.0.9410.2.0.95
710.2.0.96/2810.2.0.97 – 10.2.0.11010.2.0.111
810.2.0.112/2810.2.0.113 – 10.2.0.12610.2.0.127
910.2.0.128/2810.2.0.129 – 10.2.0.14210.2.0.143
1010.2.0.144/2810.2.0.145 – 10.2.0.15810.2.0.159
1110.2.0.160/2810.2.0.161 – 10.2.0.17410.2.0.175
1210.2.0.176/2810.2.0.177 – 10.2.0.19010.2.0.191
1310.2.0.192/2810.2.0.193 – 10.2.0.20610.2.0.207
1410.2.0.208/2810.2.0.209 – 10.2.0.22210.2.0.223
1510.2.0.224/2810.2.0.225 – 10.2.0.23810.2.0.239
1610.2.0.240/2810.2.0.241 – 10.2.0.25410.2.0.255
1710.2.1.0/2810.2.1.1 – 10.2.1.1410.2.1.15
1810.2.1.16/2810.2.1.17 – 10.2.1.3010.2.1.31
1910.2.1.32/2810.2.1.33 – 10.2.1.4610.2.1.47
2010.2.1.48/2810.2.1.49 – 10.2.1.6210.2.1.63
2110.2.1.64/2810.2.1.65 – 10.2.1.7810.2.1.79
2210.2.1.80/2810.2.1.81 – 10.2.1.9410.2.1.95
2310.2.1.96/2810.2.1.97 – 10.2.1.11010.2.1.111
2410.2.1.112/2810.2.1.113 – 10.2.1.12610.2.1.127
2510.2.1.128/2810.2.1.129 – 10.2.1.14210.2.1.143
2610.2.1.144/2810.2.1.145 – 10.2.1.15810.2.1.159
2710.2.1.160/2810.2.1.161 – 10.2.1.17410.2.1.175
2810.2.1.176/2810.2.1.177 – 10.2.1.19010.2.1.191
2910.2.1.192/2810.2.1.193 – 10.2.1.20610.2.1.207
3010.2.1.208/2810.2.1.209 – 10.2.1.22210.2.1.223
3110.2.1.224/2810.2.1.225 – 10.2.1.23810.2.1.239
3210.2.1.240/2810.2.1.241 – 10.2.1.25410.2.1.255
3310.2.2.0/2810.2.2.1 – 10.2.2.1410.2.2.15
3410.2.2.16/2810.2.2.17 – 10.2.2.3010.2.2.31
3510.2.2.32/2810.2.2.33 – 10.2.2.4610.2.2.47
3610.2.2.48/2810.2.2.49 – 10.2.2.6210.2.2.63
3710.2.2.64/2810.2.2.65 – 10.2.2.7810.2.2.79
3810.2.2.80/2810.2.2.81 – 10.2.2.9410.2.2.95
3910.2.2.96/2810.2.2.97 – 10.2.2.11010.2.2.111
4010.2.2.112/2810.2.2.113 – 10.2.2.12610.2.2.127
4110.2.2.128/2810.2.2.129 – 10.2.2.14210.2.2.143
4210.2.2.144/2810.2.2.145 – 10.2.2.15810.2.2.159
4310.2.2.160/2810.2.2.161 – 10.2.2.17410.2.2.175
4410.2.2.176/2810.2.2.177 – 10.2.2.19010.2.2.191
4510.2.2.192/2810.2.2.193 – 10.2.2.20610.2.2.207
4610.2.2.208/2810.2.2.209 – 10.2.2.22210.2.2.223
4710.2.2.224/2810.2.2.225 – 10.2.2.23810.2.2.239
4810.2.2.240/2810.2.2.241 – 10.2.2.25410.2.2.255
4910.2.3.0/2810.2.3.1 – 10.2.3.1410.2.3.15
5010.2.3.16/2810.2.3.17 – 10.2.3.3010.2.3.31
5110.2.3.32/2810.2.3.33 – 10.2.3.4610.2.3.47
5210.2.3.48/2810.2.3.49 – 10.2.3.6210.2.3.63
5310.2.3.64/2810.2.3.65 – 10.2.3.7810.2.3.79
5410.2.3.80/2810.2.3.81 – 10.2.3.9410.2.3.95
5510.2.3.96/2810.2.3.97 – 10.2.3.11010.2.3.111
5610.2.3.112/2810.2.3.113 – 10.2.3.12610.2.3.127
5710.2.3.128/2810.2.3.129 – 10.2.3.14210.2.3.143
5810.2.3.144/2810.2.3.145 – 10.2.3.15810.2.3.159
5910.2.3.160/2810.2.3.161 – 10.2.3.17410.2.3.175
6010.2.3.176/2810.2.3.177 – 10.2.3.19010.2.3.191
6110.2.3.192/2810.2.3.193 – 10.2.3.20610.2.3.207
6210.2.3.208/2810.2.3.209 – 10.2.3.22210.2.3.223
6310.2.3.224/2810.2.3.225 – 10.2.3.23810.2.3.239
6410.2.3.240/2810.2.3.241 – 10.2.3.25410.2.3.255
6510.2.4.0/2810.2.4.1 – 10.2.4.1410.2.4.15
6610.2.4.16/2810.2.4.17 – 10.2.4.3010.2.4.31
6710.2.4.32/2810.2.4.33 – 10.2.4.4610.2.4.47
6810.2.4.48/2810.2.4.49 – 10.2.4.6210.2.4.63
6910.2.4.64/2810.2.4.65 – 10.2.4.7810.2.4.79
7010.2.4.80/2810.2.4.81 – 10.2.4.9410.2.4.95
7110.2.4.96/2810.2.4.97 – 10.2.4.11010.2.4.111
7210.2.4.112/2810.2.4.113 – 10.2.4.12610.2.4.127
7310.2.4.128/2810.2.4.129 – 10.2.4.14210.2.4.143
7410.2.4.144/2810.2.4.145 – 10.2.4.15810.2.4.159
7510.2.4.160/2810.2.4.161 – 10.2.4.17410.2.4.175
7610.2.4.176/2810.2.4.177 – 10.2.4.19010.2.4.191
7710.2.4.192/2810.2.4.193 – 10.2.4.20610.2.4.207
7810.2.4.208/2810.2.4.209 – 10.2.4.22210.2.4.223
7910.2.4.224/2810.2.4.225 – 10.2.4.23810.2.4.239
8010.2.4.240/2810.2.4.241 – 10.2.4.25410.2.4.255
8110.2.5.0/2810.2.5.1 – 10.2.5.1410.2.5.15
8210.2.5.16/2810.2.5.17 – 10.2.5.3010.2.5.31
8310.2.5.32/2810.2.5.33 – 10.2.5.4610.2.5.47
8410.2.5.48/2810.2.5.49 – 10.2.5.6210.2.5.63
8510.2.5.64/2810.2.5.65 – 10.2.5.7810.2.5.79
8610.2.5.80/2810.2.5.81 – 10.2.5.9410.2.5.95
8710.2.5.96/2810.2.5.97 – 10.2.5.11010.2.5.111
8810.2.5.112/2810.2.5.113 – 10.2.5.12610.2.5.127
8910.2.5.128/2810.2.5.129 – 10.2.5.14210.2.5.143
9010.2.5.144/2810.2.5.145 – 10.2.5.15810.2.5.159
9110.2.5.160/2810.2.5.161 – 10.2.5.17410.2.5.175
9210.2.5.176/2810.2.5.177 – 10.2.5.19010.2.5.191
9310.2.5.192/2810.2.5.193 – 10.2.5.20610.2.5.207
9410.2.5.208/2810.2.5.209 – 10.2.5.22210.2.5.223
9510.2.5.224/2810.2.5.225 – 10.2.5.23810.2.5.239
9610.2.5.240/2810.2.5.241 – 10.2.5.25410.2.5.255
9710.2.6.0/2810.2.6.1 – 10.2.6.1410.2.6.15
9810.2.6.16/2810.2.6.17 – 10.2.6.3010.2.6.31
9910.2.6.32/2810.2.6.33 – 10.2.6.4610.2.6.47
10010.2.6.48/2810.2.6.49 – 10.2.6.6210.2.6.63
10110.2.6.64/2810.2.6.65 – 10.2.6.7810.2.6.79
10210.2.6.80/2810.2.6.81 – 10.2.6.9410.2.6.95
10310.2.6.96/2810.2.6.97 – 10.2.6.11010.2.6.111
10410.2.6.112/2810.2.6.113 – 10.2.6.12610.2.6.127
10510.2.6.128/2810.2.6.129 – 10.2.6.14210.2.6.143
10610.2.6.144/2810.2.6.145 – 10.2.6.15810.2.6.159
10710.2.6.160/2810.2.6.161 – 10.2.6.17410.2.6.175
10810.2.6.176/2810.2.6.177 – 10.2.6.19010.2.6.191
10910.2.6.192/2810.2.6.193 – 10.2.6.20610.2.6.207
11010.2.6.208/2810.2.6.209 – 10.2.6.22210.2.6.223
11110.2.6.224/2810.2.6.225 – 10.2.6.23810.2.6.239
11210.2.6.240/2810.2.6.241 – 10.2.6.25410.2.6.255
11310.2.7.0/2810.2.7.1 – 10.2.7.1410.2.7.15
11410.2.7.16/2810.2.7.17 – 10.2.7.3010.2.7.31
11510.2.7.32/2810.2.7.33 – 10.2.7.4610.2.7.47
11610.2.7.48/2810.2.7.49 – 10.2.7.6210.2.7.63
11710.2.7.64/2810.2.7.65 – 10.2.7.7810.2.7.79
11810.2.7.80/2810.2.7.81 – 10.2.7.9410.2.7.95
11910.2.7.96/2810.2.7.97 – 10.2.7.11010.2.7.111
12010.2.7.112/2810.2.7.113 – 10.2.7.12610.2.7.127
12110.2.7.128/2810.2.7.129 – 10.2.7.14210.2.7.143
12210.2.7.144/2810.2.7.145 – 10.2.7.15810.2.7.159
12310.2.7.160/2810.2.7.161 – 10.2.7.17410.2.7.175
12410.2.7.176/2810.2.7.177 – 10.2.7.19010.2.7.191
12510.2.7.192/2810.2.7.193 – 10.2.7.20610.2.7.207
12610.2.7.208/2810.2.7.209 – 10.2.7.22210.2.7.223
12710.2.7.224/2810.2.7.225 – 10.2.7.23810.2.7.239
12810.2.7.240/2810.2.7.241 – 10.2.7.25410.2.7.255
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 →