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)10.4.208.0/21
network10.4.208.0/21
broadcast10.4.215.255
first host10.4.208.1
last host10.4.215.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.4.208.0/21
address00001010.00000100.11010000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000100.11010000.00000000
broadcast00001010.00000100.11010111.11111111
green = network part, grey = host part
hex0x0a04d000
decimal168087552
reverse dns0.208.4.10.in-addr.arpa
ipv4-mapped::ffff:a04:d000

/21 split into /28 · 128 subnets

close ×
#networkhost rangebroadcast
110.4.208.0/2810.4.208.1 – 10.4.208.1410.4.208.15
210.4.208.16/2810.4.208.17 – 10.4.208.3010.4.208.31
310.4.208.32/2810.4.208.33 – 10.4.208.4610.4.208.47
410.4.208.48/2810.4.208.49 – 10.4.208.6210.4.208.63
510.4.208.64/2810.4.208.65 – 10.4.208.7810.4.208.79
610.4.208.80/2810.4.208.81 – 10.4.208.9410.4.208.95
710.4.208.96/2810.4.208.97 – 10.4.208.11010.4.208.111
810.4.208.112/2810.4.208.113 – 10.4.208.12610.4.208.127
910.4.208.128/2810.4.208.129 – 10.4.208.14210.4.208.143
1010.4.208.144/2810.4.208.145 – 10.4.208.15810.4.208.159
1110.4.208.160/2810.4.208.161 – 10.4.208.17410.4.208.175
1210.4.208.176/2810.4.208.177 – 10.4.208.19010.4.208.191
1310.4.208.192/2810.4.208.193 – 10.4.208.20610.4.208.207
1410.4.208.208/2810.4.208.209 – 10.4.208.22210.4.208.223
1510.4.208.224/2810.4.208.225 – 10.4.208.23810.4.208.239
1610.4.208.240/2810.4.208.241 – 10.4.208.25410.4.208.255
1710.4.209.0/2810.4.209.1 – 10.4.209.1410.4.209.15
1810.4.209.16/2810.4.209.17 – 10.4.209.3010.4.209.31
1910.4.209.32/2810.4.209.33 – 10.4.209.4610.4.209.47
2010.4.209.48/2810.4.209.49 – 10.4.209.6210.4.209.63
2110.4.209.64/2810.4.209.65 – 10.4.209.7810.4.209.79
2210.4.209.80/2810.4.209.81 – 10.4.209.9410.4.209.95
2310.4.209.96/2810.4.209.97 – 10.4.209.11010.4.209.111
2410.4.209.112/2810.4.209.113 – 10.4.209.12610.4.209.127
2510.4.209.128/2810.4.209.129 – 10.4.209.14210.4.209.143
2610.4.209.144/2810.4.209.145 – 10.4.209.15810.4.209.159
2710.4.209.160/2810.4.209.161 – 10.4.209.17410.4.209.175
2810.4.209.176/2810.4.209.177 – 10.4.209.19010.4.209.191
2910.4.209.192/2810.4.209.193 – 10.4.209.20610.4.209.207
3010.4.209.208/2810.4.209.209 – 10.4.209.22210.4.209.223
3110.4.209.224/2810.4.209.225 – 10.4.209.23810.4.209.239
3210.4.209.240/2810.4.209.241 – 10.4.209.25410.4.209.255
3310.4.210.0/2810.4.210.1 – 10.4.210.1410.4.210.15
3410.4.210.16/2810.4.210.17 – 10.4.210.3010.4.210.31
3510.4.210.32/2810.4.210.33 – 10.4.210.4610.4.210.47
3610.4.210.48/2810.4.210.49 – 10.4.210.6210.4.210.63
3710.4.210.64/2810.4.210.65 – 10.4.210.7810.4.210.79
3810.4.210.80/2810.4.210.81 – 10.4.210.9410.4.210.95
3910.4.210.96/2810.4.210.97 – 10.4.210.11010.4.210.111
4010.4.210.112/2810.4.210.113 – 10.4.210.12610.4.210.127
4110.4.210.128/2810.4.210.129 – 10.4.210.14210.4.210.143
4210.4.210.144/2810.4.210.145 – 10.4.210.15810.4.210.159
4310.4.210.160/2810.4.210.161 – 10.4.210.17410.4.210.175
4410.4.210.176/2810.4.210.177 – 10.4.210.19010.4.210.191
4510.4.210.192/2810.4.210.193 – 10.4.210.20610.4.210.207
4610.4.210.208/2810.4.210.209 – 10.4.210.22210.4.210.223
4710.4.210.224/2810.4.210.225 – 10.4.210.23810.4.210.239
4810.4.210.240/2810.4.210.241 – 10.4.210.25410.4.210.255
4910.4.211.0/2810.4.211.1 – 10.4.211.1410.4.211.15
5010.4.211.16/2810.4.211.17 – 10.4.211.3010.4.211.31
5110.4.211.32/2810.4.211.33 – 10.4.211.4610.4.211.47
5210.4.211.48/2810.4.211.49 – 10.4.211.6210.4.211.63
5310.4.211.64/2810.4.211.65 – 10.4.211.7810.4.211.79
5410.4.211.80/2810.4.211.81 – 10.4.211.9410.4.211.95
5510.4.211.96/2810.4.211.97 – 10.4.211.11010.4.211.111
5610.4.211.112/2810.4.211.113 – 10.4.211.12610.4.211.127
5710.4.211.128/2810.4.211.129 – 10.4.211.14210.4.211.143
5810.4.211.144/2810.4.211.145 – 10.4.211.15810.4.211.159
5910.4.211.160/2810.4.211.161 – 10.4.211.17410.4.211.175
6010.4.211.176/2810.4.211.177 – 10.4.211.19010.4.211.191
6110.4.211.192/2810.4.211.193 – 10.4.211.20610.4.211.207
6210.4.211.208/2810.4.211.209 – 10.4.211.22210.4.211.223
6310.4.211.224/2810.4.211.225 – 10.4.211.23810.4.211.239
6410.4.211.240/2810.4.211.241 – 10.4.211.25410.4.211.255
6510.4.212.0/2810.4.212.1 – 10.4.212.1410.4.212.15
6610.4.212.16/2810.4.212.17 – 10.4.212.3010.4.212.31
6710.4.212.32/2810.4.212.33 – 10.4.212.4610.4.212.47
6810.4.212.48/2810.4.212.49 – 10.4.212.6210.4.212.63
6910.4.212.64/2810.4.212.65 – 10.4.212.7810.4.212.79
7010.4.212.80/2810.4.212.81 – 10.4.212.9410.4.212.95
7110.4.212.96/2810.4.212.97 – 10.4.212.11010.4.212.111
7210.4.212.112/2810.4.212.113 – 10.4.212.12610.4.212.127
7310.4.212.128/2810.4.212.129 – 10.4.212.14210.4.212.143
7410.4.212.144/2810.4.212.145 – 10.4.212.15810.4.212.159
7510.4.212.160/2810.4.212.161 – 10.4.212.17410.4.212.175
7610.4.212.176/2810.4.212.177 – 10.4.212.19010.4.212.191
7710.4.212.192/2810.4.212.193 – 10.4.212.20610.4.212.207
7810.4.212.208/2810.4.212.209 – 10.4.212.22210.4.212.223
7910.4.212.224/2810.4.212.225 – 10.4.212.23810.4.212.239
8010.4.212.240/2810.4.212.241 – 10.4.212.25410.4.212.255
8110.4.213.0/2810.4.213.1 – 10.4.213.1410.4.213.15
8210.4.213.16/2810.4.213.17 – 10.4.213.3010.4.213.31
8310.4.213.32/2810.4.213.33 – 10.4.213.4610.4.213.47
8410.4.213.48/2810.4.213.49 – 10.4.213.6210.4.213.63
8510.4.213.64/2810.4.213.65 – 10.4.213.7810.4.213.79
8610.4.213.80/2810.4.213.81 – 10.4.213.9410.4.213.95
8710.4.213.96/2810.4.213.97 – 10.4.213.11010.4.213.111
8810.4.213.112/2810.4.213.113 – 10.4.213.12610.4.213.127
8910.4.213.128/2810.4.213.129 – 10.4.213.14210.4.213.143
9010.4.213.144/2810.4.213.145 – 10.4.213.15810.4.213.159
9110.4.213.160/2810.4.213.161 – 10.4.213.17410.4.213.175
9210.4.213.176/2810.4.213.177 – 10.4.213.19010.4.213.191
9310.4.213.192/2810.4.213.193 – 10.4.213.20610.4.213.207
9410.4.213.208/2810.4.213.209 – 10.4.213.22210.4.213.223
9510.4.213.224/2810.4.213.225 – 10.4.213.23810.4.213.239
9610.4.213.240/2810.4.213.241 – 10.4.213.25410.4.213.255
9710.4.214.0/2810.4.214.1 – 10.4.214.1410.4.214.15
9810.4.214.16/2810.4.214.17 – 10.4.214.3010.4.214.31
9910.4.214.32/2810.4.214.33 – 10.4.214.4610.4.214.47
10010.4.214.48/2810.4.214.49 – 10.4.214.6210.4.214.63
10110.4.214.64/2810.4.214.65 – 10.4.214.7810.4.214.79
10210.4.214.80/2810.4.214.81 – 10.4.214.9410.4.214.95
10310.4.214.96/2810.4.214.97 – 10.4.214.11010.4.214.111
10410.4.214.112/2810.4.214.113 – 10.4.214.12610.4.214.127
10510.4.214.128/2810.4.214.129 – 10.4.214.14210.4.214.143
10610.4.214.144/2810.4.214.145 – 10.4.214.15810.4.214.159
10710.4.214.160/2810.4.214.161 – 10.4.214.17410.4.214.175
10810.4.214.176/2810.4.214.177 – 10.4.214.19010.4.214.191
10910.4.214.192/2810.4.214.193 – 10.4.214.20610.4.214.207
11010.4.214.208/2810.4.214.209 – 10.4.214.22210.4.214.223
11110.4.214.224/2810.4.214.225 – 10.4.214.23810.4.214.239
11210.4.214.240/2810.4.214.241 – 10.4.214.25410.4.214.255
11310.4.215.0/2810.4.215.1 – 10.4.215.1410.4.215.15
11410.4.215.16/2810.4.215.17 – 10.4.215.3010.4.215.31
11510.4.215.32/2810.4.215.33 – 10.4.215.4610.4.215.47
11610.4.215.48/2810.4.215.49 – 10.4.215.6210.4.215.63
11710.4.215.64/2810.4.215.65 – 10.4.215.7810.4.215.79
11810.4.215.80/2810.4.215.81 – 10.4.215.9410.4.215.95
11910.4.215.96/2810.4.215.97 – 10.4.215.11010.4.215.111
12010.4.215.112/2810.4.215.113 – 10.4.215.12610.4.215.127
12110.4.215.128/2810.4.215.129 – 10.4.215.14210.4.215.143
12210.4.215.144/2810.4.215.145 – 10.4.215.15810.4.215.159
12310.4.215.160/2810.4.215.161 – 10.4.215.17410.4.215.175
12410.4.215.176/2810.4.215.177 – 10.4.215.19010.4.215.191
12510.4.215.192/2810.4.215.193 – 10.4.215.20610.4.215.207
12610.4.215.208/2810.4.215.209 – 10.4.215.22210.4.215.223
12710.4.215.224/2810.4.215.225 – 10.4.215.23810.4.215.239
12810.4.215.240/2810.4.215.241 – 10.4.215.25410.4.215.255
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 →