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)10.4.216.0/21
network10.4.216.0/21
broadcast10.4.223.255
first host10.4.216.1
last host10.4.223.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.4.216.0/21
address00001010.00000100.11011000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000100.11011000.00000000
broadcast00001010.00000100.11011111.11111111
green = network part, grey = host part
hex0x0a04d800
decimal168089600
reverse dns0.216.4.10.in-addr.arpa
ipv4-mapped::ffff:a04:d800

/21 split into /27 · 64 subnets

close ×
#networkhost rangebroadcast
110.4.216.0/2710.4.216.1 – 10.4.216.3010.4.216.31
210.4.216.32/2710.4.216.33 – 10.4.216.6210.4.216.63
310.4.216.64/2710.4.216.65 – 10.4.216.9410.4.216.95
410.4.216.96/2710.4.216.97 – 10.4.216.12610.4.216.127
510.4.216.128/2710.4.216.129 – 10.4.216.15810.4.216.159
610.4.216.160/2710.4.216.161 – 10.4.216.19010.4.216.191
710.4.216.192/2710.4.216.193 – 10.4.216.22210.4.216.223
810.4.216.224/2710.4.216.225 – 10.4.216.25410.4.216.255
910.4.217.0/2710.4.217.1 – 10.4.217.3010.4.217.31
1010.4.217.32/2710.4.217.33 – 10.4.217.6210.4.217.63
1110.4.217.64/2710.4.217.65 – 10.4.217.9410.4.217.95
1210.4.217.96/2710.4.217.97 – 10.4.217.12610.4.217.127
1310.4.217.128/2710.4.217.129 – 10.4.217.15810.4.217.159
1410.4.217.160/2710.4.217.161 – 10.4.217.19010.4.217.191
1510.4.217.192/2710.4.217.193 – 10.4.217.22210.4.217.223
1610.4.217.224/2710.4.217.225 – 10.4.217.25410.4.217.255
1710.4.218.0/2710.4.218.1 – 10.4.218.3010.4.218.31
1810.4.218.32/2710.4.218.33 – 10.4.218.6210.4.218.63
1910.4.218.64/2710.4.218.65 – 10.4.218.9410.4.218.95
2010.4.218.96/2710.4.218.97 – 10.4.218.12610.4.218.127
2110.4.218.128/2710.4.218.129 – 10.4.218.15810.4.218.159
2210.4.218.160/2710.4.218.161 – 10.4.218.19010.4.218.191
2310.4.218.192/2710.4.218.193 – 10.4.218.22210.4.218.223
2410.4.218.224/2710.4.218.225 – 10.4.218.25410.4.218.255
2510.4.219.0/2710.4.219.1 – 10.4.219.3010.4.219.31
2610.4.219.32/2710.4.219.33 – 10.4.219.6210.4.219.63
2710.4.219.64/2710.4.219.65 – 10.4.219.9410.4.219.95
2810.4.219.96/2710.4.219.97 – 10.4.219.12610.4.219.127
2910.4.219.128/2710.4.219.129 – 10.4.219.15810.4.219.159
3010.4.219.160/2710.4.219.161 – 10.4.219.19010.4.219.191
3110.4.219.192/2710.4.219.193 – 10.4.219.22210.4.219.223
3210.4.219.224/2710.4.219.225 – 10.4.219.25410.4.219.255
3310.4.220.0/2710.4.220.1 – 10.4.220.3010.4.220.31
3410.4.220.32/2710.4.220.33 – 10.4.220.6210.4.220.63
3510.4.220.64/2710.4.220.65 – 10.4.220.9410.4.220.95
3610.4.220.96/2710.4.220.97 – 10.4.220.12610.4.220.127
3710.4.220.128/2710.4.220.129 – 10.4.220.15810.4.220.159
3810.4.220.160/2710.4.220.161 – 10.4.220.19010.4.220.191
3910.4.220.192/2710.4.220.193 – 10.4.220.22210.4.220.223
4010.4.220.224/2710.4.220.225 – 10.4.220.25410.4.220.255
4110.4.221.0/2710.4.221.1 – 10.4.221.3010.4.221.31
4210.4.221.32/2710.4.221.33 – 10.4.221.6210.4.221.63
4310.4.221.64/2710.4.221.65 – 10.4.221.9410.4.221.95
4410.4.221.96/2710.4.221.97 – 10.4.221.12610.4.221.127
4510.4.221.128/2710.4.221.129 – 10.4.221.15810.4.221.159
4610.4.221.160/2710.4.221.161 – 10.4.221.19010.4.221.191
4710.4.221.192/2710.4.221.193 – 10.4.221.22210.4.221.223
4810.4.221.224/2710.4.221.225 – 10.4.221.25410.4.221.255
4910.4.222.0/2710.4.222.1 – 10.4.222.3010.4.222.31
5010.4.222.32/2710.4.222.33 – 10.4.222.6210.4.222.63
5110.4.222.64/2710.4.222.65 – 10.4.222.9410.4.222.95
5210.4.222.96/2710.4.222.97 – 10.4.222.12610.4.222.127
5310.4.222.128/2710.4.222.129 – 10.4.222.15810.4.222.159
5410.4.222.160/2710.4.222.161 – 10.4.222.19010.4.222.191
5510.4.222.192/2710.4.222.193 – 10.4.222.22210.4.222.223
5610.4.222.224/2710.4.222.225 – 10.4.222.25410.4.222.255
5710.4.223.0/2710.4.223.1 – 10.4.223.3010.4.223.31
5810.4.223.32/2710.4.223.33 – 10.4.223.6210.4.223.63
5910.4.223.64/2710.4.223.65 – 10.4.223.9410.4.223.95
6010.4.223.96/2710.4.223.97 – 10.4.223.12610.4.223.127
6110.4.223.128/2710.4.223.129 – 10.4.223.15810.4.223.159
6210.4.223.160/2710.4.223.161 – 10.4.223.19010.4.223.191
6310.4.223.192/2710.4.223.193 – 10.4.223.22210.4.223.223
6410.4.223.224/2710.4.223.225 – 10.4.223.25410.4.223.255
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 →