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)10.7.128.0/21
network10.7.128.0/21
broadcast10.7.135.255
first host10.7.128.1
last host10.7.135.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.7.128.0/21
address00001010.00000111.10000000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000111.10000000.00000000
broadcast00001010.00000111.10000111.11111111
green = network part, grey = host part
hex0x0a078000
decimal168263680
reverse dns0.128.7.10.in-addr.arpa
ipv4-mapped::ffff:a07:8000

/21 split into /28 · 128 subnets

close ×
#networkhost rangebroadcast
110.7.128.0/2810.7.128.1 – 10.7.128.1410.7.128.15
210.7.128.16/2810.7.128.17 – 10.7.128.3010.7.128.31
310.7.128.32/2810.7.128.33 – 10.7.128.4610.7.128.47
410.7.128.48/2810.7.128.49 – 10.7.128.6210.7.128.63
510.7.128.64/2810.7.128.65 – 10.7.128.7810.7.128.79
610.7.128.80/2810.7.128.81 – 10.7.128.9410.7.128.95
710.7.128.96/2810.7.128.97 – 10.7.128.11010.7.128.111
810.7.128.112/2810.7.128.113 – 10.7.128.12610.7.128.127
910.7.128.128/2810.7.128.129 – 10.7.128.14210.7.128.143
1010.7.128.144/2810.7.128.145 – 10.7.128.15810.7.128.159
1110.7.128.160/2810.7.128.161 – 10.7.128.17410.7.128.175
1210.7.128.176/2810.7.128.177 – 10.7.128.19010.7.128.191
1310.7.128.192/2810.7.128.193 – 10.7.128.20610.7.128.207
1410.7.128.208/2810.7.128.209 – 10.7.128.22210.7.128.223
1510.7.128.224/2810.7.128.225 – 10.7.128.23810.7.128.239
1610.7.128.240/2810.7.128.241 – 10.7.128.25410.7.128.255
1710.7.129.0/2810.7.129.1 – 10.7.129.1410.7.129.15
1810.7.129.16/2810.7.129.17 – 10.7.129.3010.7.129.31
1910.7.129.32/2810.7.129.33 – 10.7.129.4610.7.129.47
2010.7.129.48/2810.7.129.49 – 10.7.129.6210.7.129.63
2110.7.129.64/2810.7.129.65 – 10.7.129.7810.7.129.79
2210.7.129.80/2810.7.129.81 – 10.7.129.9410.7.129.95
2310.7.129.96/2810.7.129.97 – 10.7.129.11010.7.129.111
2410.7.129.112/2810.7.129.113 – 10.7.129.12610.7.129.127
2510.7.129.128/2810.7.129.129 – 10.7.129.14210.7.129.143
2610.7.129.144/2810.7.129.145 – 10.7.129.15810.7.129.159
2710.7.129.160/2810.7.129.161 – 10.7.129.17410.7.129.175
2810.7.129.176/2810.7.129.177 – 10.7.129.19010.7.129.191
2910.7.129.192/2810.7.129.193 – 10.7.129.20610.7.129.207
3010.7.129.208/2810.7.129.209 – 10.7.129.22210.7.129.223
3110.7.129.224/2810.7.129.225 – 10.7.129.23810.7.129.239
3210.7.129.240/2810.7.129.241 – 10.7.129.25410.7.129.255
3310.7.130.0/2810.7.130.1 – 10.7.130.1410.7.130.15
3410.7.130.16/2810.7.130.17 – 10.7.130.3010.7.130.31
3510.7.130.32/2810.7.130.33 – 10.7.130.4610.7.130.47
3610.7.130.48/2810.7.130.49 – 10.7.130.6210.7.130.63
3710.7.130.64/2810.7.130.65 – 10.7.130.7810.7.130.79
3810.7.130.80/2810.7.130.81 – 10.7.130.9410.7.130.95
3910.7.130.96/2810.7.130.97 – 10.7.130.11010.7.130.111
4010.7.130.112/2810.7.130.113 – 10.7.130.12610.7.130.127
4110.7.130.128/2810.7.130.129 – 10.7.130.14210.7.130.143
4210.7.130.144/2810.7.130.145 – 10.7.130.15810.7.130.159
4310.7.130.160/2810.7.130.161 – 10.7.130.17410.7.130.175
4410.7.130.176/2810.7.130.177 – 10.7.130.19010.7.130.191
4510.7.130.192/2810.7.130.193 – 10.7.130.20610.7.130.207
4610.7.130.208/2810.7.130.209 – 10.7.130.22210.7.130.223
4710.7.130.224/2810.7.130.225 – 10.7.130.23810.7.130.239
4810.7.130.240/2810.7.130.241 – 10.7.130.25410.7.130.255
4910.7.131.0/2810.7.131.1 – 10.7.131.1410.7.131.15
5010.7.131.16/2810.7.131.17 – 10.7.131.3010.7.131.31
5110.7.131.32/2810.7.131.33 – 10.7.131.4610.7.131.47
5210.7.131.48/2810.7.131.49 – 10.7.131.6210.7.131.63
5310.7.131.64/2810.7.131.65 – 10.7.131.7810.7.131.79
5410.7.131.80/2810.7.131.81 – 10.7.131.9410.7.131.95
5510.7.131.96/2810.7.131.97 – 10.7.131.11010.7.131.111
5610.7.131.112/2810.7.131.113 – 10.7.131.12610.7.131.127
5710.7.131.128/2810.7.131.129 – 10.7.131.14210.7.131.143
5810.7.131.144/2810.7.131.145 – 10.7.131.15810.7.131.159
5910.7.131.160/2810.7.131.161 – 10.7.131.17410.7.131.175
6010.7.131.176/2810.7.131.177 – 10.7.131.19010.7.131.191
6110.7.131.192/2810.7.131.193 – 10.7.131.20610.7.131.207
6210.7.131.208/2810.7.131.209 – 10.7.131.22210.7.131.223
6310.7.131.224/2810.7.131.225 – 10.7.131.23810.7.131.239
6410.7.131.240/2810.7.131.241 – 10.7.131.25410.7.131.255
6510.7.132.0/2810.7.132.1 – 10.7.132.1410.7.132.15
6610.7.132.16/2810.7.132.17 – 10.7.132.3010.7.132.31
6710.7.132.32/2810.7.132.33 – 10.7.132.4610.7.132.47
6810.7.132.48/2810.7.132.49 – 10.7.132.6210.7.132.63
6910.7.132.64/2810.7.132.65 – 10.7.132.7810.7.132.79
7010.7.132.80/2810.7.132.81 – 10.7.132.9410.7.132.95
7110.7.132.96/2810.7.132.97 – 10.7.132.11010.7.132.111
7210.7.132.112/2810.7.132.113 – 10.7.132.12610.7.132.127
7310.7.132.128/2810.7.132.129 – 10.7.132.14210.7.132.143
7410.7.132.144/2810.7.132.145 – 10.7.132.15810.7.132.159
7510.7.132.160/2810.7.132.161 – 10.7.132.17410.7.132.175
7610.7.132.176/2810.7.132.177 – 10.7.132.19010.7.132.191
7710.7.132.192/2810.7.132.193 – 10.7.132.20610.7.132.207
7810.7.132.208/2810.7.132.209 – 10.7.132.22210.7.132.223
7910.7.132.224/2810.7.132.225 – 10.7.132.23810.7.132.239
8010.7.132.240/2810.7.132.241 – 10.7.132.25410.7.132.255
8110.7.133.0/2810.7.133.1 – 10.7.133.1410.7.133.15
8210.7.133.16/2810.7.133.17 – 10.7.133.3010.7.133.31
8310.7.133.32/2810.7.133.33 – 10.7.133.4610.7.133.47
8410.7.133.48/2810.7.133.49 – 10.7.133.6210.7.133.63
8510.7.133.64/2810.7.133.65 – 10.7.133.7810.7.133.79
8610.7.133.80/2810.7.133.81 – 10.7.133.9410.7.133.95
8710.7.133.96/2810.7.133.97 – 10.7.133.11010.7.133.111
8810.7.133.112/2810.7.133.113 – 10.7.133.12610.7.133.127
8910.7.133.128/2810.7.133.129 – 10.7.133.14210.7.133.143
9010.7.133.144/2810.7.133.145 – 10.7.133.15810.7.133.159
9110.7.133.160/2810.7.133.161 – 10.7.133.17410.7.133.175
9210.7.133.176/2810.7.133.177 – 10.7.133.19010.7.133.191
9310.7.133.192/2810.7.133.193 – 10.7.133.20610.7.133.207
9410.7.133.208/2810.7.133.209 – 10.7.133.22210.7.133.223
9510.7.133.224/2810.7.133.225 – 10.7.133.23810.7.133.239
9610.7.133.240/2810.7.133.241 – 10.7.133.25410.7.133.255
9710.7.134.0/2810.7.134.1 – 10.7.134.1410.7.134.15
9810.7.134.16/2810.7.134.17 – 10.7.134.3010.7.134.31
9910.7.134.32/2810.7.134.33 – 10.7.134.4610.7.134.47
10010.7.134.48/2810.7.134.49 – 10.7.134.6210.7.134.63
10110.7.134.64/2810.7.134.65 – 10.7.134.7810.7.134.79
10210.7.134.80/2810.7.134.81 – 10.7.134.9410.7.134.95
10310.7.134.96/2810.7.134.97 – 10.7.134.11010.7.134.111
10410.7.134.112/2810.7.134.113 – 10.7.134.12610.7.134.127
10510.7.134.128/2810.7.134.129 – 10.7.134.14210.7.134.143
10610.7.134.144/2810.7.134.145 – 10.7.134.15810.7.134.159
10710.7.134.160/2810.7.134.161 – 10.7.134.17410.7.134.175
10810.7.134.176/2810.7.134.177 – 10.7.134.19010.7.134.191
10910.7.134.192/2810.7.134.193 – 10.7.134.20610.7.134.207
11010.7.134.208/2810.7.134.209 – 10.7.134.22210.7.134.223
11110.7.134.224/2810.7.134.225 – 10.7.134.23810.7.134.239
11210.7.134.240/2810.7.134.241 – 10.7.134.25410.7.134.255
11310.7.135.0/2810.7.135.1 – 10.7.135.1410.7.135.15
11410.7.135.16/2810.7.135.17 – 10.7.135.3010.7.135.31
11510.7.135.32/2810.7.135.33 – 10.7.135.4610.7.135.47
11610.7.135.48/2810.7.135.49 – 10.7.135.6210.7.135.63
11710.7.135.64/2810.7.135.65 – 10.7.135.7810.7.135.79
11810.7.135.80/2810.7.135.81 – 10.7.135.9410.7.135.95
11910.7.135.96/2810.7.135.97 – 10.7.135.11010.7.135.111
12010.7.135.112/2810.7.135.113 – 10.7.135.12610.7.135.127
12110.7.135.128/2810.7.135.129 – 10.7.135.14210.7.135.143
12210.7.135.144/2810.7.135.145 – 10.7.135.15810.7.135.159
12310.7.135.160/2810.7.135.161 – 10.7.135.17410.7.135.175
12410.7.135.176/2810.7.135.177 – 10.7.135.19010.7.135.191
12510.7.135.192/2810.7.135.193 – 10.7.135.20610.7.135.207
12610.7.135.208/2810.7.135.209 – 10.7.135.22210.7.135.223
12710.7.135.224/2810.7.135.225 – 10.7.135.23810.7.135.239
12810.7.135.240/2810.7.135.241 – 10.7.135.25410.7.135.255
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 →