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)10.0.208.0/21
network10.0.208.0/21
broadcast10.0.215.255
first host10.0.208.1
last host10.0.215.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.0.208.0/21
address00001010.00000000.11010000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000000.11010000.00000000
broadcast00001010.00000000.11010111.11111111
green = network part, grey = host part
hex0x0a00d000
decimal167825408
reverse dns0.208.0.10.in-addr.arpa
ipv4-mapped::ffff:a00:d000

/21 split into /28 · 128 subnets

close ×
#networkhost rangebroadcast
110.0.208.0/2810.0.208.1 – 10.0.208.1410.0.208.15
210.0.208.16/2810.0.208.17 – 10.0.208.3010.0.208.31
310.0.208.32/2810.0.208.33 – 10.0.208.4610.0.208.47
410.0.208.48/2810.0.208.49 – 10.0.208.6210.0.208.63
510.0.208.64/2810.0.208.65 – 10.0.208.7810.0.208.79
610.0.208.80/2810.0.208.81 – 10.0.208.9410.0.208.95
710.0.208.96/2810.0.208.97 – 10.0.208.11010.0.208.111
810.0.208.112/2810.0.208.113 – 10.0.208.12610.0.208.127
910.0.208.128/2810.0.208.129 – 10.0.208.14210.0.208.143
1010.0.208.144/2810.0.208.145 – 10.0.208.15810.0.208.159
1110.0.208.160/2810.0.208.161 – 10.0.208.17410.0.208.175
1210.0.208.176/2810.0.208.177 – 10.0.208.19010.0.208.191
1310.0.208.192/2810.0.208.193 – 10.0.208.20610.0.208.207
1410.0.208.208/2810.0.208.209 – 10.0.208.22210.0.208.223
1510.0.208.224/2810.0.208.225 – 10.0.208.23810.0.208.239
1610.0.208.240/2810.0.208.241 – 10.0.208.25410.0.208.255
1710.0.209.0/2810.0.209.1 – 10.0.209.1410.0.209.15
1810.0.209.16/2810.0.209.17 – 10.0.209.3010.0.209.31
1910.0.209.32/2810.0.209.33 – 10.0.209.4610.0.209.47
2010.0.209.48/2810.0.209.49 – 10.0.209.6210.0.209.63
2110.0.209.64/2810.0.209.65 – 10.0.209.7810.0.209.79
2210.0.209.80/2810.0.209.81 – 10.0.209.9410.0.209.95
2310.0.209.96/2810.0.209.97 – 10.0.209.11010.0.209.111
2410.0.209.112/2810.0.209.113 – 10.0.209.12610.0.209.127
2510.0.209.128/2810.0.209.129 – 10.0.209.14210.0.209.143
2610.0.209.144/2810.0.209.145 – 10.0.209.15810.0.209.159
2710.0.209.160/2810.0.209.161 – 10.0.209.17410.0.209.175
2810.0.209.176/2810.0.209.177 – 10.0.209.19010.0.209.191
2910.0.209.192/2810.0.209.193 – 10.0.209.20610.0.209.207
3010.0.209.208/2810.0.209.209 – 10.0.209.22210.0.209.223
3110.0.209.224/2810.0.209.225 – 10.0.209.23810.0.209.239
3210.0.209.240/2810.0.209.241 – 10.0.209.25410.0.209.255
3310.0.210.0/2810.0.210.1 – 10.0.210.1410.0.210.15
3410.0.210.16/2810.0.210.17 – 10.0.210.3010.0.210.31
3510.0.210.32/2810.0.210.33 – 10.0.210.4610.0.210.47
3610.0.210.48/2810.0.210.49 – 10.0.210.6210.0.210.63
3710.0.210.64/2810.0.210.65 – 10.0.210.7810.0.210.79
3810.0.210.80/2810.0.210.81 – 10.0.210.9410.0.210.95
3910.0.210.96/2810.0.210.97 – 10.0.210.11010.0.210.111
4010.0.210.112/2810.0.210.113 – 10.0.210.12610.0.210.127
4110.0.210.128/2810.0.210.129 – 10.0.210.14210.0.210.143
4210.0.210.144/2810.0.210.145 – 10.0.210.15810.0.210.159
4310.0.210.160/2810.0.210.161 – 10.0.210.17410.0.210.175
4410.0.210.176/2810.0.210.177 – 10.0.210.19010.0.210.191
4510.0.210.192/2810.0.210.193 – 10.0.210.20610.0.210.207
4610.0.210.208/2810.0.210.209 – 10.0.210.22210.0.210.223
4710.0.210.224/2810.0.210.225 – 10.0.210.23810.0.210.239
4810.0.210.240/2810.0.210.241 – 10.0.210.25410.0.210.255
4910.0.211.0/2810.0.211.1 – 10.0.211.1410.0.211.15
5010.0.211.16/2810.0.211.17 – 10.0.211.3010.0.211.31
5110.0.211.32/2810.0.211.33 – 10.0.211.4610.0.211.47
5210.0.211.48/2810.0.211.49 – 10.0.211.6210.0.211.63
5310.0.211.64/2810.0.211.65 – 10.0.211.7810.0.211.79
5410.0.211.80/2810.0.211.81 – 10.0.211.9410.0.211.95
5510.0.211.96/2810.0.211.97 – 10.0.211.11010.0.211.111
5610.0.211.112/2810.0.211.113 – 10.0.211.12610.0.211.127
5710.0.211.128/2810.0.211.129 – 10.0.211.14210.0.211.143
5810.0.211.144/2810.0.211.145 – 10.0.211.15810.0.211.159
5910.0.211.160/2810.0.211.161 – 10.0.211.17410.0.211.175
6010.0.211.176/2810.0.211.177 – 10.0.211.19010.0.211.191
6110.0.211.192/2810.0.211.193 – 10.0.211.20610.0.211.207
6210.0.211.208/2810.0.211.209 – 10.0.211.22210.0.211.223
6310.0.211.224/2810.0.211.225 – 10.0.211.23810.0.211.239
6410.0.211.240/2810.0.211.241 – 10.0.211.25410.0.211.255
6510.0.212.0/2810.0.212.1 – 10.0.212.1410.0.212.15
6610.0.212.16/2810.0.212.17 – 10.0.212.3010.0.212.31
6710.0.212.32/2810.0.212.33 – 10.0.212.4610.0.212.47
6810.0.212.48/2810.0.212.49 – 10.0.212.6210.0.212.63
6910.0.212.64/2810.0.212.65 – 10.0.212.7810.0.212.79
7010.0.212.80/2810.0.212.81 – 10.0.212.9410.0.212.95
7110.0.212.96/2810.0.212.97 – 10.0.212.11010.0.212.111
7210.0.212.112/2810.0.212.113 – 10.0.212.12610.0.212.127
7310.0.212.128/2810.0.212.129 – 10.0.212.14210.0.212.143
7410.0.212.144/2810.0.212.145 – 10.0.212.15810.0.212.159
7510.0.212.160/2810.0.212.161 – 10.0.212.17410.0.212.175
7610.0.212.176/2810.0.212.177 – 10.0.212.19010.0.212.191
7710.0.212.192/2810.0.212.193 – 10.0.212.20610.0.212.207
7810.0.212.208/2810.0.212.209 – 10.0.212.22210.0.212.223
7910.0.212.224/2810.0.212.225 – 10.0.212.23810.0.212.239
8010.0.212.240/2810.0.212.241 – 10.0.212.25410.0.212.255
8110.0.213.0/2810.0.213.1 – 10.0.213.1410.0.213.15
8210.0.213.16/2810.0.213.17 – 10.0.213.3010.0.213.31
8310.0.213.32/2810.0.213.33 – 10.0.213.4610.0.213.47
8410.0.213.48/2810.0.213.49 – 10.0.213.6210.0.213.63
8510.0.213.64/2810.0.213.65 – 10.0.213.7810.0.213.79
8610.0.213.80/2810.0.213.81 – 10.0.213.9410.0.213.95
8710.0.213.96/2810.0.213.97 – 10.0.213.11010.0.213.111
8810.0.213.112/2810.0.213.113 – 10.0.213.12610.0.213.127
8910.0.213.128/2810.0.213.129 – 10.0.213.14210.0.213.143
9010.0.213.144/2810.0.213.145 – 10.0.213.15810.0.213.159
9110.0.213.160/2810.0.213.161 – 10.0.213.17410.0.213.175
9210.0.213.176/2810.0.213.177 – 10.0.213.19010.0.213.191
9310.0.213.192/2810.0.213.193 – 10.0.213.20610.0.213.207
9410.0.213.208/2810.0.213.209 – 10.0.213.22210.0.213.223
9510.0.213.224/2810.0.213.225 – 10.0.213.23810.0.213.239
9610.0.213.240/2810.0.213.241 – 10.0.213.25410.0.213.255
9710.0.214.0/2810.0.214.1 – 10.0.214.1410.0.214.15
9810.0.214.16/2810.0.214.17 – 10.0.214.3010.0.214.31
9910.0.214.32/2810.0.214.33 – 10.0.214.4610.0.214.47
10010.0.214.48/2810.0.214.49 – 10.0.214.6210.0.214.63
10110.0.214.64/2810.0.214.65 – 10.0.214.7810.0.214.79
10210.0.214.80/2810.0.214.81 – 10.0.214.9410.0.214.95
10310.0.214.96/2810.0.214.97 – 10.0.214.11010.0.214.111
10410.0.214.112/2810.0.214.113 – 10.0.214.12610.0.214.127
10510.0.214.128/2810.0.214.129 – 10.0.214.14210.0.214.143
10610.0.214.144/2810.0.214.145 – 10.0.214.15810.0.214.159
10710.0.214.160/2810.0.214.161 – 10.0.214.17410.0.214.175
10810.0.214.176/2810.0.214.177 – 10.0.214.19010.0.214.191
10910.0.214.192/2810.0.214.193 – 10.0.214.20610.0.214.207
11010.0.214.208/2810.0.214.209 – 10.0.214.22210.0.214.223
11110.0.214.224/2810.0.214.225 – 10.0.214.23810.0.214.239
11210.0.214.240/2810.0.214.241 – 10.0.214.25410.0.214.255
11310.0.215.0/2810.0.215.1 – 10.0.215.1410.0.215.15
11410.0.215.16/2810.0.215.17 – 10.0.215.3010.0.215.31
11510.0.215.32/2810.0.215.33 – 10.0.215.4610.0.215.47
11610.0.215.48/2810.0.215.49 – 10.0.215.6210.0.215.63
11710.0.215.64/2810.0.215.65 – 10.0.215.7810.0.215.79
11810.0.215.80/2810.0.215.81 – 10.0.215.9410.0.215.95
11910.0.215.96/2810.0.215.97 – 10.0.215.11010.0.215.111
12010.0.215.112/2810.0.215.113 – 10.0.215.12610.0.215.127
12110.0.215.128/2810.0.215.129 – 10.0.215.14210.0.215.143
12210.0.215.144/2810.0.215.145 – 10.0.215.15810.0.215.159
12310.0.215.160/2810.0.215.161 – 10.0.215.17410.0.215.175
12410.0.215.176/2810.0.215.177 – 10.0.215.19010.0.215.191
12510.0.215.192/2810.0.215.193 – 10.0.215.20610.0.215.207
12610.0.215.208/2810.0.215.209 – 10.0.215.22210.0.215.223
12710.0.215.224/2810.0.215.225 – 10.0.215.23810.0.215.239
12810.0.215.240/2810.0.215.241 – 10.0.215.25410.0.215.255
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 →