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)10.6.248.0/21
network10.6.248.0/21
broadcast10.6.255.255
first host10.6.248.1
last host10.6.255.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.6.248.0/21
address00001010.00000110.11111000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000110.11111000.00000000
broadcast00001010.00000110.11111111.11111111
green = network part, grey = host part
hex0x0a06f800
decimal168228864
reverse dns0.248.6.10.in-addr.arpa
ipv4-mapped::ffff:a06:f800

/21 split into /28 · 128 subnets

close ×
#networkhost rangebroadcast
110.6.248.0/2810.6.248.1 – 10.6.248.1410.6.248.15
210.6.248.16/2810.6.248.17 – 10.6.248.3010.6.248.31
310.6.248.32/2810.6.248.33 – 10.6.248.4610.6.248.47
410.6.248.48/2810.6.248.49 – 10.6.248.6210.6.248.63
510.6.248.64/2810.6.248.65 – 10.6.248.7810.6.248.79
610.6.248.80/2810.6.248.81 – 10.6.248.9410.6.248.95
710.6.248.96/2810.6.248.97 – 10.6.248.11010.6.248.111
810.6.248.112/2810.6.248.113 – 10.6.248.12610.6.248.127
910.6.248.128/2810.6.248.129 – 10.6.248.14210.6.248.143
1010.6.248.144/2810.6.248.145 – 10.6.248.15810.6.248.159
1110.6.248.160/2810.6.248.161 – 10.6.248.17410.6.248.175
1210.6.248.176/2810.6.248.177 – 10.6.248.19010.6.248.191
1310.6.248.192/2810.6.248.193 – 10.6.248.20610.6.248.207
1410.6.248.208/2810.6.248.209 – 10.6.248.22210.6.248.223
1510.6.248.224/2810.6.248.225 – 10.6.248.23810.6.248.239
1610.6.248.240/2810.6.248.241 – 10.6.248.25410.6.248.255
1710.6.249.0/2810.6.249.1 – 10.6.249.1410.6.249.15
1810.6.249.16/2810.6.249.17 – 10.6.249.3010.6.249.31
1910.6.249.32/2810.6.249.33 – 10.6.249.4610.6.249.47
2010.6.249.48/2810.6.249.49 – 10.6.249.6210.6.249.63
2110.6.249.64/2810.6.249.65 – 10.6.249.7810.6.249.79
2210.6.249.80/2810.6.249.81 – 10.6.249.9410.6.249.95
2310.6.249.96/2810.6.249.97 – 10.6.249.11010.6.249.111
2410.6.249.112/2810.6.249.113 – 10.6.249.12610.6.249.127
2510.6.249.128/2810.6.249.129 – 10.6.249.14210.6.249.143
2610.6.249.144/2810.6.249.145 – 10.6.249.15810.6.249.159
2710.6.249.160/2810.6.249.161 – 10.6.249.17410.6.249.175
2810.6.249.176/2810.6.249.177 – 10.6.249.19010.6.249.191
2910.6.249.192/2810.6.249.193 – 10.6.249.20610.6.249.207
3010.6.249.208/2810.6.249.209 – 10.6.249.22210.6.249.223
3110.6.249.224/2810.6.249.225 – 10.6.249.23810.6.249.239
3210.6.249.240/2810.6.249.241 – 10.6.249.25410.6.249.255
3310.6.250.0/2810.6.250.1 – 10.6.250.1410.6.250.15
3410.6.250.16/2810.6.250.17 – 10.6.250.3010.6.250.31
3510.6.250.32/2810.6.250.33 – 10.6.250.4610.6.250.47
3610.6.250.48/2810.6.250.49 – 10.6.250.6210.6.250.63
3710.6.250.64/2810.6.250.65 – 10.6.250.7810.6.250.79
3810.6.250.80/2810.6.250.81 – 10.6.250.9410.6.250.95
3910.6.250.96/2810.6.250.97 – 10.6.250.11010.6.250.111
4010.6.250.112/2810.6.250.113 – 10.6.250.12610.6.250.127
4110.6.250.128/2810.6.250.129 – 10.6.250.14210.6.250.143
4210.6.250.144/2810.6.250.145 – 10.6.250.15810.6.250.159
4310.6.250.160/2810.6.250.161 – 10.6.250.17410.6.250.175
4410.6.250.176/2810.6.250.177 – 10.6.250.19010.6.250.191
4510.6.250.192/2810.6.250.193 – 10.6.250.20610.6.250.207
4610.6.250.208/2810.6.250.209 – 10.6.250.22210.6.250.223
4710.6.250.224/2810.6.250.225 – 10.6.250.23810.6.250.239
4810.6.250.240/2810.6.250.241 – 10.6.250.25410.6.250.255
4910.6.251.0/2810.6.251.1 – 10.6.251.1410.6.251.15
5010.6.251.16/2810.6.251.17 – 10.6.251.3010.6.251.31
5110.6.251.32/2810.6.251.33 – 10.6.251.4610.6.251.47
5210.6.251.48/2810.6.251.49 – 10.6.251.6210.6.251.63
5310.6.251.64/2810.6.251.65 – 10.6.251.7810.6.251.79
5410.6.251.80/2810.6.251.81 – 10.6.251.9410.6.251.95
5510.6.251.96/2810.6.251.97 – 10.6.251.11010.6.251.111
5610.6.251.112/2810.6.251.113 – 10.6.251.12610.6.251.127
5710.6.251.128/2810.6.251.129 – 10.6.251.14210.6.251.143
5810.6.251.144/2810.6.251.145 – 10.6.251.15810.6.251.159
5910.6.251.160/2810.6.251.161 – 10.6.251.17410.6.251.175
6010.6.251.176/2810.6.251.177 – 10.6.251.19010.6.251.191
6110.6.251.192/2810.6.251.193 – 10.6.251.20610.6.251.207
6210.6.251.208/2810.6.251.209 – 10.6.251.22210.6.251.223
6310.6.251.224/2810.6.251.225 – 10.6.251.23810.6.251.239
6410.6.251.240/2810.6.251.241 – 10.6.251.25410.6.251.255
6510.6.252.0/2810.6.252.1 – 10.6.252.1410.6.252.15
6610.6.252.16/2810.6.252.17 – 10.6.252.3010.6.252.31
6710.6.252.32/2810.6.252.33 – 10.6.252.4610.6.252.47
6810.6.252.48/2810.6.252.49 – 10.6.252.6210.6.252.63
6910.6.252.64/2810.6.252.65 – 10.6.252.7810.6.252.79
7010.6.252.80/2810.6.252.81 – 10.6.252.9410.6.252.95
7110.6.252.96/2810.6.252.97 – 10.6.252.11010.6.252.111
7210.6.252.112/2810.6.252.113 – 10.6.252.12610.6.252.127
7310.6.252.128/2810.6.252.129 – 10.6.252.14210.6.252.143
7410.6.252.144/2810.6.252.145 – 10.6.252.15810.6.252.159
7510.6.252.160/2810.6.252.161 – 10.6.252.17410.6.252.175
7610.6.252.176/2810.6.252.177 – 10.6.252.19010.6.252.191
7710.6.252.192/2810.6.252.193 – 10.6.252.20610.6.252.207
7810.6.252.208/2810.6.252.209 – 10.6.252.22210.6.252.223
7910.6.252.224/2810.6.252.225 – 10.6.252.23810.6.252.239
8010.6.252.240/2810.6.252.241 – 10.6.252.25410.6.252.255
8110.6.253.0/2810.6.253.1 – 10.6.253.1410.6.253.15
8210.6.253.16/2810.6.253.17 – 10.6.253.3010.6.253.31
8310.6.253.32/2810.6.253.33 – 10.6.253.4610.6.253.47
8410.6.253.48/2810.6.253.49 – 10.6.253.6210.6.253.63
8510.6.253.64/2810.6.253.65 – 10.6.253.7810.6.253.79
8610.6.253.80/2810.6.253.81 – 10.6.253.9410.6.253.95
8710.6.253.96/2810.6.253.97 – 10.6.253.11010.6.253.111
8810.6.253.112/2810.6.253.113 – 10.6.253.12610.6.253.127
8910.6.253.128/2810.6.253.129 – 10.6.253.14210.6.253.143
9010.6.253.144/2810.6.253.145 – 10.6.253.15810.6.253.159
9110.6.253.160/2810.6.253.161 – 10.6.253.17410.6.253.175
9210.6.253.176/2810.6.253.177 – 10.6.253.19010.6.253.191
9310.6.253.192/2810.6.253.193 – 10.6.253.20610.6.253.207
9410.6.253.208/2810.6.253.209 – 10.6.253.22210.6.253.223
9510.6.253.224/2810.6.253.225 – 10.6.253.23810.6.253.239
9610.6.253.240/2810.6.253.241 – 10.6.253.25410.6.253.255
9710.6.254.0/2810.6.254.1 – 10.6.254.1410.6.254.15
9810.6.254.16/2810.6.254.17 – 10.6.254.3010.6.254.31
9910.6.254.32/2810.6.254.33 – 10.6.254.4610.6.254.47
10010.6.254.48/2810.6.254.49 – 10.6.254.6210.6.254.63
10110.6.254.64/2810.6.254.65 – 10.6.254.7810.6.254.79
10210.6.254.80/2810.6.254.81 – 10.6.254.9410.6.254.95
10310.6.254.96/2810.6.254.97 – 10.6.254.11010.6.254.111
10410.6.254.112/2810.6.254.113 – 10.6.254.12610.6.254.127
10510.6.254.128/2810.6.254.129 – 10.6.254.14210.6.254.143
10610.6.254.144/2810.6.254.145 – 10.6.254.15810.6.254.159
10710.6.254.160/2810.6.254.161 – 10.6.254.17410.6.254.175
10810.6.254.176/2810.6.254.177 – 10.6.254.19010.6.254.191
10910.6.254.192/2810.6.254.193 – 10.6.254.20610.6.254.207
11010.6.254.208/2810.6.254.209 – 10.6.254.22210.6.254.223
11110.6.254.224/2810.6.254.225 – 10.6.254.23810.6.254.239
11210.6.254.240/2810.6.254.241 – 10.6.254.25410.6.254.255
11310.6.255.0/2810.6.255.1 – 10.6.255.1410.6.255.15
11410.6.255.16/2810.6.255.17 – 10.6.255.3010.6.255.31
11510.6.255.32/2810.6.255.33 – 10.6.255.4610.6.255.47
11610.6.255.48/2810.6.255.49 – 10.6.255.6210.6.255.63
11710.6.255.64/2810.6.255.65 – 10.6.255.7810.6.255.79
11810.6.255.80/2810.6.255.81 – 10.6.255.9410.6.255.95
11910.6.255.96/2810.6.255.97 – 10.6.255.11010.6.255.111
12010.6.255.112/2810.6.255.113 – 10.6.255.12610.6.255.127
12110.6.255.128/2810.6.255.129 – 10.6.255.14210.6.255.143
12210.6.255.144/2810.6.255.145 – 10.6.255.15810.6.255.159
12310.6.255.160/2810.6.255.161 – 10.6.255.17410.6.255.175
12410.6.255.176/2810.6.255.177 – 10.6.255.19010.6.255.191
12510.6.255.192/2810.6.255.193 – 10.6.255.20610.6.255.207
12610.6.255.208/2810.6.255.209 – 10.6.255.22210.6.255.223
12710.6.255.224/2810.6.255.225 – 10.6.255.23810.6.255.239
12810.6.255.240/2810.6.255.241 – 10.6.255.25410.6.255.255
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 →