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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)10.7.136.0/21
network10.7.136.0/21
broadcast10.7.143.255
first host10.7.136.1
last host10.7.143.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.7.136.0/21
address00001010.00000111.10001000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000111.10001000.00000000
broadcast00001010.00000111.10001111.11111111
green = network part, grey = host part
hex0x0a078800
decimal168265728
reverse dns0.136.7.10.in-addr.arpa
ipv4-mapped::ffff:a07:8800

/21 split into /27 · 64 subnets

close ×
#networkhost rangebroadcast
110.7.136.0/2710.7.136.1 – 10.7.136.3010.7.136.31
210.7.136.32/2710.7.136.33 – 10.7.136.6210.7.136.63
310.7.136.64/2710.7.136.65 – 10.7.136.9410.7.136.95
410.7.136.96/2710.7.136.97 – 10.7.136.12610.7.136.127
510.7.136.128/2710.7.136.129 – 10.7.136.15810.7.136.159
610.7.136.160/2710.7.136.161 – 10.7.136.19010.7.136.191
710.7.136.192/2710.7.136.193 – 10.7.136.22210.7.136.223
810.7.136.224/2710.7.136.225 – 10.7.136.25410.7.136.255
910.7.137.0/2710.7.137.1 – 10.7.137.3010.7.137.31
1010.7.137.32/2710.7.137.33 – 10.7.137.6210.7.137.63
1110.7.137.64/2710.7.137.65 – 10.7.137.9410.7.137.95
1210.7.137.96/2710.7.137.97 – 10.7.137.12610.7.137.127
1310.7.137.128/2710.7.137.129 – 10.7.137.15810.7.137.159
1410.7.137.160/2710.7.137.161 – 10.7.137.19010.7.137.191
1510.7.137.192/2710.7.137.193 – 10.7.137.22210.7.137.223
1610.7.137.224/2710.7.137.225 – 10.7.137.25410.7.137.255
1710.7.138.0/2710.7.138.1 – 10.7.138.3010.7.138.31
1810.7.138.32/2710.7.138.33 – 10.7.138.6210.7.138.63
1910.7.138.64/2710.7.138.65 – 10.7.138.9410.7.138.95
2010.7.138.96/2710.7.138.97 – 10.7.138.12610.7.138.127
2110.7.138.128/2710.7.138.129 – 10.7.138.15810.7.138.159
2210.7.138.160/2710.7.138.161 – 10.7.138.19010.7.138.191
2310.7.138.192/2710.7.138.193 – 10.7.138.22210.7.138.223
2410.7.138.224/2710.7.138.225 – 10.7.138.25410.7.138.255
2510.7.139.0/2710.7.139.1 – 10.7.139.3010.7.139.31
2610.7.139.32/2710.7.139.33 – 10.7.139.6210.7.139.63
2710.7.139.64/2710.7.139.65 – 10.7.139.9410.7.139.95
2810.7.139.96/2710.7.139.97 – 10.7.139.12610.7.139.127
2910.7.139.128/2710.7.139.129 – 10.7.139.15810.7.139.159
3010.7.139.160/2710.7.139.161 – 10.7.139.19010.7.139.191
3110.7.139.192/2710.7.139.193 – 10.7.139.22210.7.139.223
3210.7.139.224/2710.7.139.225 – 10.7.139.25410.7.139.255
3310.7.140.0/2710.7.140.1 – 10.7.140.3010.7.140.31
3410.7.140.32/2710.7.140.33 – 10.7.140.6210.7.140.63
3510.7.140.64/2710.7.140.65 – 10.7.140.9410.7.140.95
3610.7.140.96/2710.7.140.97 – 10.7.140.12610.7.140.127
3710.7.140.128/2710.7.140.129 – 10.7.140.15810.7.140.159
3810.7.140.160/2710.7.140.161 – 10.7.140.19010.7.140.191
3910.7.140.192/2710.7.140.193 – 10.7.140.22210.7.140.223
4010.7.140.224/2710.7.140.225 – 10.7.140.25410.7.140.255
4110.7.141.0/2710.7.141.1 – 10.7.141.3010.7.141.31
4210.7.141.32/2710.7.141.33 – 10.7.141.6210.7.141.63
4310.7.141.64/2710.7.141.65 – 10.7.141.9410.7.141.95
4410.7.141.96/2710.7.141.97 – 10.7.141.12610.7.141.127
4510.7.141.128/2710.7.141.129 – 10.7.141.15810.7.141.159
4610.7.141.160/2710.7.141.161 – 10.7.141.19010.7.141.191
4710.7.141.192/2710.7.141.193 – 10.7.141.22210.7.141.223
4810.7.141.224/2710.7.141.225 – 10.7.141.25410.7.141.255
4910.7.142.0/2710.7.142.1 – 10.7.142.3010.7.142.31
5010.7.142.32/2710.7.142.33 – 10.7.142.6210.7.142.63
5110.7.142.64/2710.7.142.65 – 10.7.142.9410.7.142.95
5210.7.142.96/2710.7.142.97 – 10.7.142.12610.7.142.127
5310.7.142.128/2710.7.142.129 – 10.7.142.15810.7.142.159
5410.7.142.160/2710.7.142.161 – 10.7.142.19010.7.142.191
5510.7.142.192/2710.7.142.193 – 10.7.142.22210.7.142.223
5610.7.142.224/2710.7.142.225 – 10.7.142.25410.7.142.255
5710.7.143.0/2710.7.143.1 – 10.7.143.3010.7.143.31
5810.7.143.32/2710.7.143.33 – 10.7.143.6210.7.143.63
5910.7.143.64/2710.7.143.65 – 10.7.143.9410.7.143.95
6010.7.143.96/2710.7.143.97 – 10.7.143.12610.7.143.127
6110.7.143.128/2710.7.143.129 – 10.7.143.15810.7.143.159
6210.7.143.160/2710.7.143.161 – 10.7.143.19010.7.143.191
6310.7.143.192/2710.7.143.193 – 10.7.143.22210.7.143.223
6410.7.143.224/2710.7.143.225 – 10.7.143.25410.7.143.255
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 →