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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)10.7.104.0/21
network10.7.104.0/21
broadcast10.7.111.255
first host10.7.104.1
last host10.7.111.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.7.104.0/21
address00001010.00000111.01101000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000111.01101000.00000000
broadcast00001010.00000111.01101111.11111111
green = network part, grey = host part
hex0x0a076800
decimal168257536
reverse dns0.104.7.10.in-addr.arpa
ipv4-mapped::ffff:a07:6800

/21 split into /27 · 64 subnets

close ×
#networkhost rangebroadcast
110.7.104.0/2710.7.104.1 – 10.7.104.3010.7.104.31
210.7.104.32/2710.7.104.33 – 10.7.104.6210.7.104.63
310.7.104.64/2710.7.104.65 – 10.7.104.9410.7.104.95
410.7.104.96/2710.7.104.97 – 10.7.104.12610.7.104.127
510.7.104.128/2710.7.104.129 – 10.7.104.15810.7.104.159
610.7.104.160/2710.7.104.161 – 10.7.104.19010.7.104.191
710.7.104.192/2710.7.104.193 – 10.7.104.22210.7.104.223
810.7.104.224/2710.7.104.225 – 10.7.104.25410.7.104.255
910.7.105.0/2710.7.105.1 – 10.7.105.3010.7.105.31
1010.7.105.32/2710.7.105.33 – 10.7.105.6210.7.105.63
1110.7.105.64/2710.7.105.65 – 10.7.105.9410.7.105.95
1210.7.105.96/2710.7.105.97 – 10.7.105.12610.7.105.127
1310.7.105.128/2710.7.105.129 – 10.7.105.15810.7.105.159
1410.7.105.160/2710.7.105.161 – 10.7.105.19010.7.105.191
1510.7.105.192/2710.7.105.193 – 10.7.105.22210.7.105.223
1610.7.105.224/2710.7.105.225 – 10.7.105.25410.7.105.255
1710.7.106.0/2710.7.106.1 – 10.7.106.3010.7.106.31
1810.7.106.32/2710.7.106.33 – 10.7.106.6210.7.106.63
1910.7.106.64/2710.7.106.65 – 10.7.106.9410.7.106.95
2010.7.106.96/2710.7.106.97 – 10.7.106.12610.7.106.127
2110.7.106.128/2710.7.106.129 – 10.7.106.15810.7.106.159
2210.7.106.160/2710.7.106.161 – 10.7.106.19010.7.106.191
2310.7.106.192/2710.7.106.193 – 10.7.106.22210.7.106.223
2410.7.106.224/2710.7.106.225 – 10.7.106.25410.7.106.255
2510.7.107.0/2710.7.107.1 – 10.7.107.3010.7.107.31
2610.7.107.32/2710.7.107.33 – 10.7.107.6210.7.107.63
2710.7.107.64/2710.7.107.65 – 10.7.107.9410.7.107.95
2810.7.107.96/2710.7.107.97 – 10.7.107.12610.7.107.127
2910.7.107.128/2710.7.107.129 – 10.7.107.15810.7.107.159
3010.7.107.160/2710.7.107.161 – 10.7.107.19010.7.107.191
3110.7.107.192/2710.7.107.193 – 10.7.107.22210.7.107.223
3210.7.107.224/2710.7.107.225 – 10.7.107.25410.7.107.255
3310.7.108.0/2710.7.108.1 – 10.7.108.3010.7.108.31
3410.7.108.32/2710.7.108.33 – 10.7.108.6210.7.108.63
3510.7.108.64/2710.7.108.65 – 10.7.108.9410.7.108.95
3610.7.108.96/2710.7.108.97 – 10.7.108.12610.7.108.127
3710.7.108.128/2710.7.108.129 – 10.7.108.15810.7.108.159
3810.7.108.160/2710.7.108.161 – 10.7.108.19010.7.108.191
3910.7.108.192/2710.7.108.193 – 10.7.108.22210.7.108.223
4010.7.108.224/2710.7.108.225 – 10.7.108.25410.7.108.255
4110.7.109.0/2710.7.109.1 – 10.7.109.3010.7.109.31
4210.7.109.32/2710.7.109.33 – 10.7.109.6210.7.109.63
4310.7.109.64/2710.7.109.65 – 10.7.109.9410.7.109.95
4410.7.109.96/2710.7.109.97 – 10.7.109.12610.7.109.127
4510.7.109.128/2710.7.109.129 – 10.7.109.15810.7.109.159
4610.7.109.160/2710.7.109.161 – 10.7.109.19010.7.109.191
4710.7.109.192/2710.7.109.193 – 10.7.109.22210.7.109.223
4810.7.109.224/2710.7.109.225 – 10.7.109.25410.7.109.255
4910.7.110.0/2710.7.110.1 – 10.7.110.3010.7.110.31
5010.7.110.32/2710.7.110.33 – 10.7.110.6210.7.110.63
5110.7.110.64/2710.7.110.65 – 10.7.110.9410.7.110.95
5210.7.110.96/2710.7.110.97 – 10.7.110.12610.7.110.127
5310.7.110.128/2710.7.110.129 – 10.7.110.15810.7.110.159
5410.7.110.160/2710.7.110.161 – 10.7.110.19010.7.110.191
5510.7.110.192/2710.7.110.193 – 10.7.110.22210.7.110.223
5610.7.110.224/2710.7.110.225 – 10.7.110.25410.7.110.255
5710.7.111.0/2710.7.111.1 – 10.7.111.3010.7.111.31
5810.7.111.32/2710.7.111.33 – 10.7.111.6210.7.111.63
5910.7.111.64/2710.7.111.65 – 10.7.111.9410.7.111.95
6010.7.111.96/2710.7.111.97 – 10.7.111.12610.7.111.127
6110.7.111.128/2710.7.111.129 – 10.7.111.15810.7.111.159
6210.7.111.160/2710.7.111.161 – 10.7.111.19010.7.111.191
6310.7.111.192/2710.7.111.193 – 10.7.111.22210.7.111.223
6410.7.111.224/2710.7.111.225 – 10.7.111.25410.7.111.255
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 →