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)10.0.248.0/21
network10.0.248.0/21
broadcast10.0.255.255
first host10.0.248.1
last host10.0.255.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.0.248.0/21
address00001010.00000000.11111000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000000.11111000.00000000
broadcast00001010.00000000.11111111.11111111
green = network part, grey = host part
hex0x0a00f800
decimal167835648
reverse dns0.248.0.10.in-addr.arpa
ipv4-mapped::ffff:a00:f800

/21 split into /27 · 64 subnets

close ×
#networkhost rangebroadcast
110.0.248.0/2710.0.248.1 – 10.0.248.3010.0.248.31
210.0.248.32/2710.0.248.33 – 10.0.248.6210.0.248.63
310.0.248.64/2710.0.248.65 – 10.0.248.9410.0.248.95
410.0.248.96/2710.0.248.97 – 10.0.248.12610.0.248.127
510.0.248.128/2710.0.248.129 – 10.0.248.15810.0.248.159
610.0.248.160/2710.0.248.161 – 10.0.248.19010.0.248.191
710.0.248.192/2710.0.248.193 – 10.0.248.22210.0.248.223
810.0.248.224/2710.0.248.225 – 10.0.248.25410.0.248.255
910.0.249.0/2710.0.249.1 – 10.0.249.3010.0.249.31
1010.0.249.32/2710.0.249.33 – 10.0.249.6210.0.249.63
1110.0.249.64/2710.0.249.65 – 10.0.249.9410.0.249.95
1210.0.249.96/2710.0.249.97 – 10.0.249.12610.0.249.127
1310.0.249.128/2710.0.249.129 – 10.0.249.15810.0.249.159
1410.0.249.160/2710.0.249.161 – 10.0.249.19010.0.249.191
1510.0.249.192/2710.0.249.193 – 10.0.249.22210.0.249.223
1610.0.249.224/2710.0.249.225 – 10.0.249.25410.0.249.255
1710.0.250.0/2710.0.250.1 – 10.0.250.3010.0.250.31
1810.0.250.32/2710.0.250.33 – 10.0.250.6210.0.250.63
1910.0.250.64/2710.0.250.65 – 10.0.250.9410.0.250.95
2010.0.250.96/2710.0.250.97 – 10.0.250.12610.0.250.127
2110.0.250.128/2710.0.250.129 – 10.0.250.15810.0.250.159
2210.0.250.160/2710.0.250.161 – 10.0.250.19010.0.250.191
2310.0.250.192/2710.0.250.193 – 10.0.250.22210.0.250.223
2410.0.250.224/2710.0.250.225 – 10.0.250.25410.0.250.255
2510.0.251.0/2710.0.251.1 – 10.0.251.3010.0.251.31
2610.0.251.32/2710.0.251.33 – 10.0.251.6210.0.251.63
2710.0.251.64/2710.0.251.65 – 10.0.251.9410.0.251.95
2810.0.251.96/2710.0.251.97 – 10.0.251.12610.0.251.127
2910.0.251.128/2710.0.251.129 – 10.0.251.15810.0.251.159
3010.0.251.160/2710.0.251.161 – 10.0.251.19010.0.251.191
3110.0.251.192/2710.0.251.193 – 10.0.251.22210.0.251.223
3210.0.251.224/2710.0.251.225 – 10.0.251.25410.0.251.255
3310.0.252.0/2710.0.252.1 – 10.0.252.3010.0.252.31
3410.0.252.32/2710.0.252.33 – 10.0.252.6210.0.252.63
3510.0.252.64/2710.0.252.65 – 10.0.252.9410.0.252.95
3610.0.252.96/2710.0.252.97 – 10.0.252.12610.0.252.127
3710.0.252.128/2710.0.252.129 – 10.0.252.15810.0.252.159
3810.0.252.160/2710.0.252.161 – 10.0.252.19010.0.252.191
3910.0.252.192/2710.0.252.193 – 10.0.252.22210.0.252.223
4010.0.252.224/2710.0.252.225 – 10.0.252.25410.0.252.255
4110.0.253.0/2710.0.253.1 – 10.0.253.3010.0.253.31
4210.0.253.32/2710.0.253.33 – 10.0.253.6210.0.253.63
4310.0.253.64/2710.0.253.65 – 10.0.253.9410.0.253.95
4410.0.253.96/2710.0.253.97 – 10.0.253.12610.0.253.127
4510.0.253.128/2710.0.253.129 – 10.0.253.15810.0.253.159
4610.0.253.160/2710.0.253.161 – 10.0.253.19010.0.253.191
4710.0.253.192/2710.0.253.193 – 10.0.253.22210.0.253.223
4810.0.253.224/2710.0.253.225 – 10.0.253.25410.0.253.255
4910.0.254.0/2710.0.254.1 – 10.0.254.3010.0.254.31
5010.0.254.32/2710.0.254.33 – 10.0.254.6210.0.254.63
5110.0.254.64/2710.0.254.65 – 10.0.254.9410.0.254.95
5210.0.254.96/2710.0.254.97 – 10.0.254.12610.0.254.127
5310.0.254.128/2710.0.254.129 – 10.0.254.15810.0.254.159
5410.0.254.160/2710.0.254.161 – 10.0.254.19010.0.254.191
5510.0.254.192/2710.0.254.193 – 10.0.254.22210.0.254.223
5610.0.254.224/2710.0.254.225 – 10.0.254.25410.0.254.255
5710.0.255.0/2710.0.255.1 – 10.0.255.3010.0.255.31
5810.0.255.32/2710.0.255.33 – 10.0.255.6210.0.255.63
5910.0.255.64/2710.0.255.65 – 10.0.255.9410.0.255.95
6010.0.255.96/2710.0.255.97 – 10.0.255.12610.0.255.127
6110.0.255.128/2710.0.255.129 – 10.0.255.15810.0.255.159
6210.0.255.160/2710.0.255.161 – 10.0.255.19010.0.255.191
6310.0.255.192/2710.0.255.193 – 10.0.255.22210.0.255.223
6410.0.255.224/2710.0.255.225 – 10.0.255.25410.0.255.255
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 →