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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)10.6.192.0/21
network10.6.192.0/21
broadcast10.6.199.255
first host10.6.192.1
last host10.6.199.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.6.192.0/21
address00001010.00000110.11000000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000110.11000000.00000000
broadcast00001010.00000110.11000111.11111111
green = network part, grey = host part
hex0x0a06c000
decimal168214528
reverse dns0.192.6.10.in-addr.arpa
ipv4-mapped::ffff:a06:c000

/21 split into /27 · 64 subnets

close ×
#networkhost rangebroadcast
110.6.192.0/2710.6.192.1 – 10.6.192.3010.6.192.31
210.6.192.32/2710.6.192.33 – 10.6.192.6210.6.192.63
310.6.192.64/2710.6.192.65 – 10.6.192.9410.6.192.95
410.6.192.96/2710.6.192.97 – 10.6.192.12610.6.192.127
510.6.192.128/2710.6.192.129 – 10.6.192.15810.6.192.159
610.6.192.160/2710.6.192.161 – 10.6.192.19010.6.192.191
710.6.192.192/2710.6.192.193 – 10.6.192.22210.6.192.223
810.6.192.224/2710.6.192.225 – 10.6.192.25410.6.192.255
910.6.193.0/2710.6.193.1 – 10.6.193.3010.6.193.31
1010.6.193.32/2710.6.193.33 – 10.6.193.6210.6.193.63
1110.6.193.64/2710.6.193.65 – 10.6.193.9410.6.193.95
1210.6.193.96/2710.6.193.97 – 10.6.193.12610.6.193.127
1310.6.193.128/2710.6.193.129 – 10.6.193.15810.6.193.159
1410.6.193.160/2710.6.193.161 – 10.6.193.19010.6.193.191
1510.6.193.192/2710.6.193.193 – 10.6.193.22210.6.193.223
1610.6.193.224/2710.6.193.225 – 10.6.193.25410.6.193.255
1710.6.194.0/2710.6.194.1 – 10.6.194.3010.6.194.31
1810.6.194.32/2710.6.194.33 – 10.6.194.6210.6.194.63
1910.6.194.64/2710.6.194.65 – 10.6.194.9410.6.194.95
2010.6.194.96/2710.6.194.97 – 10.6.194.12610.6.194.127
2110.6.194.128/2710.6.194.129 – 10.6.194.15810.6.194.159
2210.6.194.160/2710.6.194.161 – 10.6.194.19010.6.194.191
2310.6.194.192/2710.6.194.193 – 10.6.194.22210.6.194.223
2410.6.194.224/2710.6.194.225 – 10.6.194.25410.6.194.255
2510.6.195.0/2710.6.195.1 – 10.6.195.3010.6.195.31
2610.6.195.32/2710.6.195.33 – 10.6.195.6210.6.195.63
2710.6.195.64/2710.6.195.65 – 10.6.195.9410.6.195.95
2810.6.195.96/2710.6.195.97 – 10.6.195.12610.6.195.127
2910.6.195.128/2710.6.195.129 – 10.6.195.15810.6.195.159
3010.6.195.160/2710.6.195.161 – 10.6.195.19010.6.195.191
3110.6.195.192/2710.6.195.193 – 10.6.195.22210.6.195.223
3210.6.195.224/2710.6.195.225 – 10.6.195.25410.6.195.255
3310.6.196.0/2710.6.196.1 – 10.6.196.3010.6.196.31
3410.6.196.32/2710.6.196.33 – 10.6.196.6210.6.196.63
3510.6.196.64/2710.6.196.65 – 10.6.196.9410.6.196.95
3610.6.196.96/2710.6.196.97 – 10.6.196.12610.6.196.127
3710.6.196.128/2710.6.196.129 – 10.6.196.15810.6.196.159
3810.6.196.160/2710.6.196.161 – 10.6.196.19010.6.196.191
3910.6.196.192/2710.6.196.193 – 10.6.196.22210.6.196.223
4010.6.196.224/2710.6.196.225 – 10.6.196.25410.6.196.255
4110.6.197.0/2710.6.197.1 – 10.6.197.3010.6.197.31
4210.6.197.32/2710.6.197.33 – 10.6.197.6210.6.197.63
4310.6.197.64/2710.6.197.65 – 10.6.197.9410.6.197.95
4410.6.197.96/2710.6.197.97 – 10.6.197.12610.6.197.127
4510.6.197.128/2710.6.197.129 – 10.6.197.15810.6.197.159
4610.6.197.160/2710.6.197.161 – 10.6.197.19010.6.197.191
4710.6.197.192/2710.6.197.193 – 10.6.197.22210.6.197.223
4810.6.197.224/2710.6.197.225 – 10.6.197.25410.6.197.255
4910.6.198.0/2710.6.198.1 – 10.6.198.3010.6.198.31
5010.6.198.32/2710.6.198.33 – 10.6.198.6210.6.198.63
5110.6.198.64/2710.6.198.65 – 10.6.198.9410.6.198.95
5210.6.198.96/2710.6.198.97 – 10.6.198.12610.6.198.127
5310.6.198.128/2710.6.198.129 – 10.6.198.15810.6.198.159
5410.6.198.160/2710.6.198.161 – 10.6.198.19010.6.198.191
5510.6.198.192/2710.6.198.193 – 10.6.198.22210.6.198.223
5610.6.198.224/2710.6.198.225 – 10.6.198.25410.6.198.255
5710.6.199.0/2710.6.199.1 – 10.6.199.3010.6.199.31
5810.6.199.32/2710.6.199.33 – 10.6.199.6210.6.199.63
5910.6.199.64/2710.6.199.65 – 10.6.199.9410.6.199.95
6010.6.199.96/2710.6.199.97 – 10.6.199.12610.6.199.127
6110.6.199.128/2710.6.199.129 – 10.6.199.15810.6.199.159
6210.6.199.160/2710.6.199.161 – 10.6.199.19010.6.199.191
6310.6.199.192/2710.6.199.193 – 10.6.199.22210.6.199.223
6410.6.199.224/2710.6.199.225 – 10.6.199.25410.6.199.255
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 →