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)10.7.40.0/21
network10.7.40.0/21
broadcast10.7.47.255
first host10.7.40.1
last host10.7.47.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.7.40.0/21
address00001010.00000111.00101000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000111.00101000.00000000
broadcast00001010.00000111.00101111.11111111
green = network part, grey = host part
hex0x0a072800
decimal168241152
reverse dns0.40.7.10.in-addr.arpa
ipv4-mapped::ffff:a07:2800

/21 split into /28 · 128 subnets

close ×
#networkhost rangebroadcast
110.7.40.0/2810.7.40.1 – 10.7.40.1410.7.40.15
210.7.40.16/2810.7.40.17 – 10.7.40.3010.7.40.31
310.7.40.32/2810.7.40.33 – 10.7.40.4610.7.40.47
410.7.40.48/2810.7.40.49 – 10.7.40.6210.7.40.63
510.7.40.64/2810.7.40.65 – 10.7.40.7810.7.40.79
610.7.40.80/2810.7.40.81 – 10.7.40.9410.7.40.95
710.7.40.96/2810.7.40.97 – 10.7.40.11010.7.40.111
810.7.40.112/2810.7.40.113 – 10.7.40.12610.7.40.127
910.7.40.128/2810.7.40.129 – 10.7.40.14210.7.40.143
1010.7.40.144/2810.7.40.145 – 10.7.40.15810.7.40.159
1110.7.40.160/2810.7.40.161 – 10.7.40.17410.7.40.175
1210.7.40.176/2810.7.40.177 – 10.7.40.19010.7.40.191
1310.7.40.192/2810.7.40.193 – 10.7.40.20610.7.40.207
1410.7.40.208/2810.7.40.209 – 10.7.40.22210.7.40.223
1510.7.40.224/2810.7.40.225 – 10.7.40.23810.7.40.239
1610.7.40.240/2810.7.40.241 – 10.7.40.25410.7.40.255
1710.7.41.0/2810.7.41.1 – 10.7.41.1410.7.41.15
1810.7.41.16/2810.7.41.17 – 10.7.41.3010.7.41.31
1910.7.41.32/2810.7.41.33 – 10.7.41.4610.7.41.47
2010.7.41.48/2810.7.41.49 – 10.7.41.6210.7.41.63
2110.7.41.64/2810.7.41.65 – 10.7.41.7810.7.41.79
2210.7.41.80/2810.7.41.81 – 10.7.41.9410.7.41.95
2310.7.41.96/2810.7.41.97 – 10.7.41.11010.7.41.111
2410.7.41.112/2810.7.41.113 – 10.7.41.12610.7.41.127
2510.7.41.128/2810.7.41.129 – 10.7.41.14210.7.41.143
2610.7.41.144/2810.7.41.145 – 10.7.41.15810.7.41.159
2710.7.41.160/2810.7.41.161 – 10.7.41.17410.7.41.175
2810.7.41.176/2810.7.41.177 – 10.7.41.19010.7.41.191
2910.7.41.192/2810.7.41.193 – 10.7.41.20610.7.41.207
3010.7.41.208/2810.7.41.209 – 10.7.41.22210.7.41.223
3110.7.41.224/2810.7.41.225 – 10.7.41.23810.7.41.239
3210.7.41.240/2810.7.41.241 – 10.7.41.25410.7.41.255
3310.7.42.0/2810.7.42.1 – 10.7.42.1410.7.42.15
3410.7.42.16/2810.7.42.17 – 10.7.42.3010.7.42.31
3510.7.42.32/2810.7.42.33 – 10.7.42.4610.7.42.47
3610.7.42.48/2810.7.42.49 – 10.7.42.6210.7.42.63
3710.7.42.64/2810.7.42.65 – 10.7.42.7810.7.42.79
3810.7.42.80/2810.7.42.81 – 10.7.42.9410.7.42.95
3910.7.42.96/2810.7.42.97 – 10.7.42.11010.7.42.111
4010.7.42.112/2810.7.42.113 – 10.7.42.12610.7.42.127
4110.7.42.128/2810.7.42.129 – 10.7.42.14210.7.42.143
4210.7.42.144/2810.7.42.145 – 10.7.42.15810.7.42.159
4310.7.42.160/2810.7.42.161 – 10.7.42.17410.7.42.175
4410.7.42.176/2810.7.42.177 – 10.7.42.19010.7.42.191
4510.7.42.192/2810.7.42.193 – 10.7.42.20610.7.42.207
4610.7.42.208/2810.7.42.209 – 10.7.42.22210.7.42.223
4710.7.42.224/2810.7.42.225 – 10.7.42.23810.7.42.239
4810.7.42.240/2810.7.42.241 – 10.7.42.25410.7.42.255
4910.7.43.0/2810.7.43.1 – 10.7.43.1410.7.43.15
5010.7.43.16/2810.7.43.17 – 10.7.43.3010.7.43.31
5110.7.43.32/2810.7.43.33 – 10.7.43.4610.7.43.47
5210.7.43.48/2810.7.43.49 – 10.7.43.6210.7.43.63
5310.7.43.64/2810.7.43.65 – 10.7.43.7810.7.43.79
5410.7.43.80/2810.7.43.81 – 10.7.43.9410.7.43.95
5510.7.43.96/2810.7.43.97 – 10.7.43.11010.7.43.111
5610.7.43.112/2810.7.43.113 – 10.7.43.12610.7.43.127
5710.7.43.128/2810.7.43.129 – 10.7.43.14210.7.43.143
5810.7.43.144/2810.7.43.145 – 10.7.43.15810.7.43.159
5910.7.43.160/2810.7.43.161 – 10.7.43.17410.7.43.175
6010.7.43.176/2810.7.43.177 – 10.7.43.19010.7.43.191
6110.7.43.192/2810.7.43.193 – 10.7.43.20610.7.43.207
6210.7.43.208/2810.7.43.209 – 10.7.43.22210.7.43.223
6310.7.43.224/2810.7.43.225 – 10.7.43.23810.7.43.239
6410.7.43.240/2810.7.43.241 – 10.7.43.25410.7.43.255
6510.7.44.0/2810.7.44.1 – 10.7.44.1410.7.44.15
6610.7.44.16/2810.7.44.17 – 10.7.44.3010.7.44.31
6710.7.44.32/2810.7.44.33 – 10.7.44.4610.7.44.47
6810.7.44.48/2810.7.44.49 – 10.7.44.6210.7.44.63
6910.7.44.64/2810.7.44.65 – 10.7.44.7810.7.44.79
7010.7.44.80/2810.7.44.81 – 10.7.44.9410.7.44.95
7110.7.44.96/2810.7.44.97 – 10.7.44.11010.7.44.111
7210.7.44.112/2810.7.44.113 – 10.7.44.12610.7.44.127
7310.7.44.128/2810.7.44.129 – 10.7.44.14210.7.44.143
7410.7.44.144/2810.7.44.145 – 10.7.44.15810.7.44.159
7510.7.44.160/2810.7.44.161 – 10.7.44.17410.7.44.175
7610.7.44.176/2810.7.44.177 – 10.7.44.19010.7.44.191
7710.7.44.192/2810.7.44.193 – 10.7.44.20610.7.44.207
7810.7.44.208/2810.7.44.209 – 10.7.44.22210.7.44.223
7910.7.44.224/2810.7.44.225 – 10.7.44.23810.7.44.239
8010.7.44.240/2810.7.44.241 – 10.7.44.25410.7.44.255
8110.7.45.0/2810.7.45.1 – 10.7.45.1410.7.45.15
8210.7.45.16/2810.7.45.17 – 10.7.45.3010.7.45.31
8310.7.45.32/2810.7.45.33 – 10.7.45.4610.7.45.47
8410.7.45.48/2810.7.45.49 – 10.7.45.6210.7.45.63
8510.7.45.64/2810.7.45.65 – 10.7.45.7810.7.45.79
8610.7.45.80/2810.7.45.81 – 10.7.45.9410.7.45.95
8710.7.45.96/2810.7.45.97 – 10.7.45.11010.7.45.111
8810.7.45.112/2810.7.45.113 – 10.7.45.12610.7.45.127
8910.7.45.128/2810.7.45.129 – 10.7.45.14210.7.45.143
9010.7.45.144/2810.7.45.145 – 10.7.45.15810.7.45.159
9110.7.45.160/2810.7.45.161 – 10.7.45.17410.7.45.175
9210.7.45.176/2810.7.45.177 – 10.7.45.19010.7.45.191
9310.7.45.192/2810.7.45.193 – 10.7.45.20610.7.45.207
9410.7.45.208/2810.7.45.209 – 10.7.45.22210.7.45.223
9510.7.45.224/2810.7.45.225 – 10.7.45.23810.7.45.239
9610.7.45.240/2810.7.45.241 – 10.7.45.25410.7.45.255
9710.7.46.0/2810.7.46.1 – 10.7.46.1410.7.46.15
9810.7.46.16/2810.7.46.17 – 10.7.46.3010.7.46.31
9910.7.46.32/2810.7.46.33 – 10.7.46.4610.7.46.47
10010.7.46.48/2810.7.46.49 – 10.7.46.6210.7.46.63
10110.7.46.64/2810.7.46.65 – 10.7.46.7810.7.46.79
10210.7.46.80/2810.7.46.81 – 10.7.46.9410.7.46.95
10310.7.46.96/2810.7.46.97 – 10.7.46.11010.7.46.111
10410.7.46.112/2810.7.46.113 – 10.7.46.12610.7.46.127
10510.7.46.128/2810.7.46.129 – 10.7.46.14210.7.46.143
10610.7.46.144/2810.7.46.145 – 10.7.46.15810.7.46.159
10710.7.46.160/2810.7.46.161 – 10.7.46.17410.7.46.175
10810.7.46.176/2810.7.46.177 – 10.7.46.19010.7.46.191
10910.7.46.192/2810.7.46.193 – 10.7.46.20610.7.46.207
11010.7.46.208/2810.7.46.209 – 10.7.46.22210.7.46.223
11110.7.46.224/2810.7.46.225 – 10.7.46.23810.7.46.239
11210.7.46.240/2810.7.46.241 – 10.7.46.25410.7.46.255
11310.7.47.0/2810.7.47.1 – 10.7.47.1410.7.47.15
11410.7.47.16/2810.7.47.17 – 10.7.47.3010.7.47.31
11510.7.47.32/2810.7.47.33 – 10.7.47.4610.7.47.47
11610.7.47.48/2810.7.47.49 – 10.7.47.6210.7.47.63
11710.7.47.64/2810.7.47.65 – 10.7.47.7810.7.47.79
11810.7.47.80/2810.7.47.81 – 10.7.47.9410.7.47.95
11910.7.47.96/2810.7.47.97 – 10.7.47.11010.7.47.111
12010.7.47.112/2810.7.47.113 – 10.7.47.12610.7.47.127
12110.7.47.128/2810.7.47.129 – 10.7.47.14210.7.47.143
12210.7.47.144/2810.7.47.145 – 10.7.47.15810.7.47.159
12310.7.47.160/2810.7.47.161 – 10.7.47.17410.7.47.175
12410.7.47.176/2810.7.47.177 – 10.7.47.19010.7.47.191
12510.7.47.192/2810.7.47.193 – 10.7.47.20610.7.47.207
12610.7.47.208/2810.7.47.209 – 10.7.47.22210.7.47.223
12710.7.47.224/2810.7.47.225 – 10.7.47.23810.7.47.239
12810.7.47.240/2810.7.47.241 – 10.7.47.25410.7.47.255
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 →