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)10.78.40.0/21
network10.78.40.0/21
broadcast10.78.47.255
first host10.78.40.1
last host10.78.47.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.78.40.0/21
address00001010.01001110.00101000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.01001110.00101000.00000000
broadcast00001010.01001110.00101111.11111111
green = network part, grey = host part
hex0x0a4e2800
decimal172894208
reverse dns0.40.78.10.in-addr.arpa
ipv4-mapped::ffff:a4e:2800

/21 split into /28 · 128 subnets

close ×
#networkhost rangebroadcast
110.78.40.0/2810.78.40.1 – 10.78.40.1410.78.40.15
210.78.40.16/2810.78.40.17 – 10.78.40.3010.78.40.31
310.78.40.32/2810.78.40.33 – 10.78.40.4610.78.40.47
410.78.40.48/2810.78.40.49 – 10.78.40.6210.78.40.63
510.78.40.64/2810.78.40.65 – 10.78.40.7810.78.40.79
610.78.40.80/2810.78.40.81 – 10.78.40.9410.78.40.95
710.78.40.96/2810.78.40.97 – 10.78.40.11010.78.40.111
810.78.40.112/2810.78.40.113 – 10.78.40.12610.78.40.127
910.78.40.128/2810.78.40.129 – 10.78.40.14210.78.40.143
1010.78.40.144/2810.78.40.145 – 10.78.40.15810.78.40.159
1110.78.40.160/2810.78.40.161 – 10.78.40.17410.78.40.175
1210.78.40.176/2810.78.40.177 – 10.78.40.19010.78.40.191
1310.78.40.192/2810.78.40.193 – 10.78.40.20610.78.40.207
1410.78.40.208/2810.78.40.209 – 10.78.40.22210.78.40.223
1510.78.40.224/2810.78.40.225 – 10.78.40.23810.78.40.239
1610.78.40.240/2810.78.40.241 – 10.78.40.25410.78.40.255
1710.78.41.0/2810.78.41.1 – 10.78.41.1410.78.41.15
1810.78.41.16/2810.78.41.17 – 10.78.41.3010.78.41.31
1910.78.41.32/2810.78.41.33 – 10.78.41.4610.78.41.47
2010.78.41.48/2810.78.41.49 – 10.78.41.6210.78.41.63
2110.78.41.64/2810.78.41.65 – 10.78.41.7810.78.41.79
2210.78.41.80/2810.78.41.81 – 10.78.41.9410.78.41.95
2310.78.41.96/2810.78.41.97 – 10.78.41.11010.78.41.111
2410.78.41.112/2810.78.41.113 – 10.78.41.12610.78.41.127
2510.78.41.128/2810.78.41.129 – 10.78.41.14210.78.41.143
2610.78.41.144/2810.78.41.145 – 10.78.41.15810.78.41.159
2710.78.41.160/2810.78.41.161 – 10.78.41.17410.78.41.175
2810.78.41.176/2810.78.41.177 – 10.78.41.19010.78.41.191
2910.78.41.192/2810.78.41.193 – 10.78.41.20610.78.41.207
3010.78.41.208/2810.78.41.209 – 10.78.41.22210.78.41.223
3110.78.41.224/2810.78.41.225 – 10.78.41.23810.78.41.239
3210.78.41.240/2810.78.41.241 – 10.78.41.25410.78.41.255
3310.78.42.0/2810.78.42.1 – 10.78.42.1410.78.42.15
3410.78.42.16/2810.78.42.17 – 10.78.42.3010.78.42.31
3510.78.42.32/2810.78.42.33 – 10.78.42.4610.78.42.47
3610.78.42.48/2810.78.42.49 – 10.78.42.6210.78.42.63
3710.78.42.64/2810.78.42.65 – 10.78.42.7810.78.42.79
3810.78.42.80/2810.78.42.81 – 10.78.42.9410.78.42.95
3910.78.42.96/2810.78.42.97 – 10.78.42.11010.78.42.111
4010.78.42.112/2810.78.42.113 – 10.78.42.12610.78.42.127
4110.78.42.128/2810.78.42.129 – 10.78.42.14210.78.42.143
4210.78.42.144/2810.78.42.145 – 10.78.42.15810.78.42.159
4310.78.42.160/2810.78.42.161 – 10.78.42.17410.78.42.175
4410.78.42.176/2810.78.42.177 – 10.78.42.19010.78.42.191
4510.78.42.192/2810.78.42.193 – 10.78.42.20610.78.42.207
4610.78.42.208/2810.78.42.209 – 10.78.42.22210.78.42.223
4710.78.42.224/2810.78.42.225 – 10.78.42.23810.78.42.239
4810.78.42.240/2810.78.42.241 – 10.78.42.25410.78.42.255
4910.78.43.0/2810.78.43.1 – 10.78.43.1410.78.43.15
5010.78.43.16/2810.78.43.17 – 10.78.43.3010.78.43.31
5110.78.43.32/2810.78.43.33 – 10.78.43.4610.78.43.47
5210.78.43.48/2810.78.43.49 – 10.78.43.6210.78.43.63
5310.78.43.64/2810.78.43.65 – 10.78.43.7810.78.43.79
5410.78.43.80/2810.78.43.81 – 10.78.43.9410.78.43.95
5510.78.43.96/2810.78.43.97 – 10.78.43.11010.78.43.111
5610.78.43.112/2810.78.43.113 – 10.78.43.12610.78.43.127
5710.78.43.128/2810.78.43.129 – 10.78.43.14210.78.43.143
5810.78.43.144/2810.78.43.145 – 10.78.43.15810.78.43.159
5910.78.43.160/2810.78.43.161 – 10.78.43.17410.78.43.175
6010.78.43.176/2810.78.43.177 – 10.78.43.19010.78.43.191
6110.78.43.192/2810.78.43.193 – 10.78.43.20610.78.43.207
6210.78.43.208/2810.78.43.209 – 10.78.43.22210.78.43.223
6310.78.43.224/2810.78.43.225 – 10.78.43.23810.78.43.239
6410.78.43.240/2810.78.43.241 – 10.78.43.25410.78.43.255
6510.78.44.0/2810.78.44.1 – 10.78.44.1410.78.44.15
6610.78.44.16/2810.78.44.17 – 10.78.44.3010.78.44.31
6710.78.44.32/2810.78.44.33 – 10.78.44.4610.78.44.47
6810.78.44.48/2810.78.44.49 – 10.78.44.6210.78.44.63
6910.78.44.64/2810.78.44.65 – 10.78.44.7810.78.44.79
7010.78.44.80/2810.78.44.81 – 10.78.44.9410.78.44.95
7110.78.44.96/2810.78.44.97 – 10.78.44.11010.78.44.111
7210.78.44.112/2810.78.44.113 – 10.78.44.12610.78.44.127
7310.78.44.128/2810.78.44.129 – 10.78.44.14210.78.44.143
7410.78.44.144/2810.78.44.145 – 10.78.44.15810.78.44.159
7510.78.44.160/2810.78.44.161 – 10.78.44.17410.78.44.175
7610.78.44.176/2810.78.44.177 – 10.78.44.19010.78.44.191
7710.78.44.192/2810.78.44.193 – 10.78.44.20610.78.44.207
7810.78.44.208/2810.78.44.209 – 10.78.44.22210.78.44.223
7910.78.44.224/2810.78.44.225 – 10.78.44.23810.78.44.239
8010.78.44.240/2810.78.44.241 – 10.78.44.25410.78.44.255
8110.78.45.0/2810.78.45.1 – 10.78.45.1410.78.45.15
8210.78.45.16/2810.78.45.17 – 10.78.45.3010.78.45.31
8310.78.45.32/2810.78.45.33 – 10.78.45.4610.78.45.47
8410.78.45.48/2810.78.45.49 – 10.78.45.6210.78.45.63
8510.78.45.64/2810.78.45.65 – 10.78.45.7810.78.45.79
8610.78.45.80/2810.78.45.81 – 10.78.45.9410.78.45.95
8710.78.45.96/2810.78.45.97 – 10.78.45.11010.78.45.111
8810.78.45.112/2810.78.45.113 – 10.78.45.12610.78.45.127
8910.78.45.128/2810.78.45.129 – 10.78.45.14210.78.45.143
9010.78.45.144/2810.78.45.145 – 10.78.45.15810.78.45.159
9110.78.45.160/2810.78.45.161 – 10.78.45.17410.78.45.175
9210.78.45.176/2810.78.45.177 – 10.78.45.19010.78.45.191
9310.78.45.192/2810.78.45.193 – 10.78.45.20610.78.45.207
9410.78.45.208/2810.78.45.209 – 10.78.45.22210.78.45.223
9510.78.45.224/2810.78.45.225 – 10.78.45.23810.78.45.239
9610.78.45.240/2810.78.45.241 – 10.78.45.25410.78.45.255
9710.78.46.0/2810.78.46.1 – 10.78.46.1410.78.46.15
9810.78.46.16/2810.78.46.17 – 10.78.46.3010.78.46.31
9910.78.46.32/2810.78.46.33 – 10.78.46.4610.78.46.47
10010.78.46.48/2810.78.46.49 – 10.78.46.6210.78.46.63
10110.78.46.64/2810.78.46.65 – 10.78.46.7810.78.46.79
10210.78.46.80/2810.78.46.81 – 10.78.46.9410.78.46.95
10310.78.46.96/2810.78.46.97 – 10.78.46.11010.78.46.111
10410.78.46.112/2810.78.46.113 – 10.78.46.12610.78.46.127
10510.78.46.128/2810.78.46.129 – 10.78.46.14210.78.46.143
10610.78.46.144/2810.78.46.145 – 10.78.46.15810.78.46.159
10710.78.46.160/2810.78.46.161 – 10.78.46.17410.78.46.175
10810.78.46.176/2810.78.46.177 – 10.78.46.19010.78.46.191
10910.78.46.192/2810.78.46.193 – 10.78.46.20610.78.46.207
11010.78.46.208/2810.78.46.209 – 10.78.46.22210.78.46.223
11110.78.46.224/2810.78.46.225 – 10.78.46.23810.78.46.239
11210.78.46.240/2810.78.46.241 – 10.78.46.25410.78.46.255
11310.78.47.0/2810.78.47.1 – 10.78.47.1410.78.47.15
11410.78.47.16/2810.78.47.17 – 10.78.47.3010.78.47.31
11510.78.47.32/2810.78.47.33 – 10.78.47.4610.78.47.47
11610.78.47.48/2810.78.47.49 – 10.78.47.6210.78.47.63
11710.78.47.64/2810.78.47.65 – 10.78.47.7810.78.47.79
11810.78.47.80/2810.78.47.81 – 10.78.47.9410.78.47.95
11910.78.47.96/2810.78.47.97 – 10.78.47.11010.78.47.111
12010.78.47.112/2810.78.47.113 – 10.78.47.12610.78.47.127
12110.78.47.128/2810.78.47.129 – 10.78.47.14210.78.47.143
12210.78.47.144/2810.78.47.145 – 10.78.47.15810.78.47.159
12310.78.47.160/2810.78.47.161 – 10.78.47.17410.78.47.175
12410.78.47.176/2810.78.47.177 – 10.78.47.19010.78.47.191
12510.78.47.192/2810.78.47.193 – 10.78.47.20610.78.47.207
12610.78.47.208/2810.78.47.209 – 10.78.47.22210.78.47.223
12710.78.47.224/2810.78.47.225 – 10.78.47.23810.78.47.239
12810.78.47.240/2810.78.47.241 – 10.78.47.25410.78.47.255
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 →