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)10.3.64.0/21
network10.3.64.0/21
broadcast10.3.71.255
first host10.3.64.1
last host10.3.71.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.3.64.0/21
address00001010.00000011.01000000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000011.01000000.00000000
broadcast00001010.00000011.01000111.11111111
green = network part, grey = host part
hex0x0a034000
decimal167985152
reverse dns0.64.3.10.in-addr.arpa
ipv4-mapped::ffff:a03:4000

/21 split into /28 · 128 subnets

close ×
#networkhost rangebroadcast
110.3.64.0/2810.3.64.1 – 10.3.64.1410.3.64.15
210.3.64.16/2810.3.64.17 – 10.3.64.3010.3.64.31
310.3.64.32/2810.3.64.33 – 10.3.64.4610.3.64.47
410.3.64.48/2810.3.64.49 – 10.3.64.6210.3.64.63
510.3.64.64/2810.3.64.65 – 10.3.64.7810.3.64.79
610.3.64.80/2810.3.64.81 – 10.3.64.9410.3.64.95
710.3.64.96/2810.3.64.97 – 10.3.64.11010.3.64.111
810.3.64.112/2810.3.64.113 – 10.3.64.12610.3.64.127
910.3.64.128/2810.3.64.129 – 10.3.64.14210.3.64.143
1010.3.64.144/2810.3.64.145 – 10.3.64.15810.3.64.159
1110.3.64.160/2810.3.64.161 – 10.3.64.17410.3.64.175
1210.3.64.176/2810.3.64.177 – 10.3.64.19010.3.64.191
1310.3.64.192/2810.3.64.193 – 10.3.64.20610.3.64.207
1410.3.64.208/2810.3.64.209 – 10.3.64.22210.3.64.223
1510.3.64.224/2810.3.64.225 – 10.3.64.23810.3.64.239
1610.3.64.240/2810.3.64.241 – 10.3.64.25410.3.64.255
1710.3.65.0/2810.3.65.1 – 10.3.65.1410.3.65.15
1810.3.65.16/2810.3.65.17 – 10.3.65.3010.3.65.31
1910.3.65.32/2810.3.65.33 – 10.3.65.4610.3.65.47
2010.3.65.48/2810.3.65.49 – 10.3.65.6210.3.65.63
2110.3.65.64/2810.3.65.65 – 10.3.65.7810.3.65.79
2210.3.65.80/2810.3.65.81 – 10.3.65.9410.3.65.95
2310.3.65.96/2810.3.65.97 – 10.3.65.11010.3.65.111
2410.3.65.112/2810.3.65.113 – 10.3.65.12610.3.65.127
2510.3.65.128/2810.3.65.129 – 10.3.65.14210.3.65.143
2610.3.65.144/2810.3.65.145 – 10.3.65.15810.3.65.159
2710.3.65.160/2810.3.65.161 – 10.3.65.17410.3.65.175
2810.3.65.176/2810.3.65.177 – 10.3.65.19010.3.65.191
2910.3.65.192/2810.3.65.193 – 10.3.65.20610.3.65.207
3010.3.65.208/2810.3.65.209 – 10.3.65.22210.3.65.223
3110.3.65.224/2810.3.65.225 – 10.3.65.23810.3.65.239
3210.3.65.240/2810.3.65.241 – 10.3.65.25410.3.65.255
3310.3.66.0/2810.3.66.1 – 10.3.66.1410.3.66.15
3410.3.66.16/2810.3.66.17 – 10.3.66.3010.3.66.31
3510.3.66.32/2810.3.66.33 – 10.3.66.4610.3.66.47
3610.3.66.48/2810.3.66.49 – 10.3.66.6210.3.66.63
3710.3.66.64/2810.3.66.65 – 10.3.66.7810.3.66.79
3810.3.66.80/2810.3.66.81 – 10.3.66.9410.3.66.95
3910.3.66.96/2810.3.66.97 – 10.3.66.11010.3.66.111
4010.3.66.112/2810.3.66.113 – 10.3.66.12610.3.66.127
4110.3.66.128/2810.3.66.129 – 10.3.66.14210.3.66.143
4210.3.66.144/2810.3.66.145 – 10.3.66.15810.3.66.159
4310.3.66.160/2810.3.66.161 – 10.3.66.17410.3.66.175
4410.3.66.176/2810.3.66.177 – 10.3.66.19010.3.66.191
4510.3.66.192/2810.3.66.193 – 10.3.66.20610.3.66.207
4610.3.66.208/2810.3.66.209 – 10.3.66.22210.3.66.223
4710.3.66.224/2810.3.66.225 – 10.3.66.23810.3.66.239
4810.3.66.240/2810.3.66.241 – 10.3.66.25410.3.66.255
4910.3.67.0/2810.3.67.1 – 10.3.67.1410.3.67.15
5010.3.67.16/2810.3.67.17 – 10.3.67.3010.3.67.31
5110.3.67.32/2810.3.67.33 – 10.3.67.4610.3.67.47
5210.3.67.48/2810.3.67.49 – 10.3.67.6210.3.67.63
5310.3.67.64/2810.3.67.65 – 10.3.67.7810.3.67.79
5410.3.67.80/2810.3.67.81 – 10.3.67.9410.3.67.95
5510.3.67.96/2810.3.67.97 – 10.3.67.11010.3.67.111
5610.3.67.112/2810.3.67.113 – 10.3.67.12610.3.67.127
5710.3.67.128/2810.3.67.129 – 10.3.67.14210.3.67.143
5810.3.67.144/2810.3.67.145 – 10.3.67.15810.3.67.159
5910.3.67.160/2810.3.67.161 – 10.3.67.17410.3.67.175
6010.3.67.176/2810.3.67.177 – 10.3.67.19010.3.67.191
6110.3.67.192/2810.3.67.193 – 10.3.67.20610.3.67.207
6210.3.67.208/2810.3.67.209 – 10.3.67.22210.3.67.223
6310.3.67.224/2810.3.67.225 – 10.3.67.23810.3.67.239
6410.3.67.240/2810.3.67.241 – 10.3.67.25410.3.67.255
6510.3.68.0/2810.3.68.1 – 10.3.68.1410.3.68.15
6610.3.68.16/2810.3.68.17 – 10.3.68.3010.3.68.31
6710.3.68.32/2810.3.68.33 – 10.3.68.4610.3.68.47
6810.3.68.48/2810.3.68.49 – 10.3.68.6210.3.68.63
6910.3.68.64/2810.3.68.65 – 10.3.68.7810.3.68.79
7010.3.68.80/2810.3.68.81 – 10.3.68.9410.3.68.95
7110.3.68.96/2810.3.68.97 – 10.3.68.11010.3.68.111
7210.3.68.112/2810.3.68.113 – 10.3.68.12610.3.68.127
7310.3.68.128/2810.3.68.129 – 10.3.68.14210.3.68.143
7410.3.68.144/2810.3.68.145 – 10.3.68.15810.3.68.159
7510.3.68.160/2810.3.68.161 – 10.3.68.17410.3.68.175
7610.3.68.176/2810.3.68.177 – 10.3.68.19010.3.68.191
7710.3.68.192/2810.3.68.193 – 10.3.68.20610.3.68.207
7810.3.68.208/2810.3.68.209 – 10.3.68.22210.3.68.223
7910.3.68.224/2810.3.68.225 – 10.3.68.23810.3.68.239
8010.3.68.240/2810.3.68.241 – 10.3.68.25410.3.68.255
8110.3.69.0/2810.3.69.1 – 10.3.69.1410.3.69.15
8210.3.69.16/2810.3.69.17 – 10.3.69.3010.3.69.31
8310.3.69.32/2810.3.69.33 – 10.3.69.4610.3.69.47
8410.3.69.48/2810.3.69.49 – 10.3.69.6210.3.69.63
8510.3.69.64/2810.3.69.65 – 10.3.69.7810.3.69.79
8610.3.69.80/2810.3.69.81 – 10.3.69.9410.3.69.95
8710.3.69.96/2810.3.69.97 – 10.3.69.11010.3.69.111
8810.3.69.112/2810.3.69.113 – 10.3.69.12610.3.69.127
8910.3.69.128/2810.3.69.129 – 10.3.69.14210.3.69.143
9010.3.69.144/2810.3.69.145 – 10.3.69.15810.3.69.159
9110.3.69.160/2810.3.69.161 – 10.3.69.17410.3.69.175
9210.3.69.176/2810.3.69.177 – 10.3.69.19010.3.69.191
9310.3.69.192/2810.3.69.193 – 10.3.69.20610.3.69.207
9410.3.69.208/2810.3.69.209 – 10.3.69.22210.3.69.223
9510.3.69.224/2810.3.69.225 – 10.3.69.23810.3.69.239
9610.3.69.240/2810.3.69.241 – 10.3.69.25410.3.69.255
9710.3.70.0/2810.3.70.1 – 10.3.70.1410.3.70.15
9810.3.70.16/2810.3.70.17 – 10.3.70.3010.3.70.31
9910.3.70.32/2810.3.70.33 – 10.3.70.4610.3.70.47
10010.3.70.48/2810.3.70.49 – 10.3.70.6210.3.70.63
10110.3.70.64/2810.3.70.65 – 10.3.70.7810.3.70.79
10210.3.70.80/2810.3.70.81 – 10.3.70.9410.3.70.95
10310.3.70.96/2810.3.70.97 – 10.3.70.11010.3.70.111
10410.3.70.112/2810.3.70.113 – 10.3.70.12610.3.70.127
10510.3.70.128/2810.3.70.129 – 10.3.70.14210.3.70.143
10610.3.70.144/2810.3.70.145 – 10.3.70.15810.3.70.159
10710.3.70.160/2810.3.70.161 – 10.3.70.17410.3.70.175
10810.3.70.176/2810.3.70.177 – 10.3.70.19010.3.70.191
10910.3.70.192/2810.3.70.193 – 10.3.70.20610.3.70.207
11010.3.70.208/2810.3.70.209 – 10.3.70.22210.3.70.223
11110.3.70.224/2810.3.70.225 – 10.3.70.23810.3.70.239
11210.3.70.240/2810.3.70.241 – 10.3.70.25410.3.70.255
11310.3.71.0/2810.3.71.1 – 10.3.71.1410.3.71.15
11410.3.71.16/2810.3.71.17 – 10.3.71.3010.3.71.31
11510.3.71.32/2810.3.71.33 – 10.3.71.4610.3.71.47
11610.3.71.48/2810.3.71.49 – 10.3.71.6210.3.71.63
11710.3.71.64/2810.3.71.65 – 10.3.71.7810.3.71.79
11810.3.71.80/2810.3.71.81 – 10.3.71.9410.3.71.95
11910.3.71.96/2810.3.71.97 – 10.3.71.11010.3.71.111
12010.3.71.112/2810.3.71.113 – 10.3.71.12610.3.71.127
12110.3.71.128/2810.3.71.129 – 10.3.71.14210.3.71.143
12210.3.71.144/2810.3.71.145 – 10.3.71.15810.3.71.159
12310.3.71.160/2810.3.71.161 – 10.3.71.17410.3.71.175
12410.3.71.176/2810.3.71.177 – 10.3.71.19010.3.71.191
12510.3.71.192/2810.3.71.193 – 10.3.71.20610.3.71.207
12610.3.71.208/2810.3.71.209 – 10.3.71.22210.3.71.223
12710.3.71.224/2810.3.71.225 – 10.3.71.23810.3.71.239
12810.3.71.240/2810.3.71.241 – 10.3.71.25410.3.71.255
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 →