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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)10.6.200.0/21
network10.6.200.0/21
broadcast10.6.207.255
first host10.6.200.1
last host10.6.207.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.6.200.0/21
address00001010.00000110.11001000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000110.11001000.00000000
broadcast00001010.00000110.11001111.11111111
green = network part, grey = host part
hex0x0a06c800
decimal168216576
reverse dns0.200.6.10.in-addr.arpa
ipv4-mapped::ffff:a06:c800

/21 split into /27 · 64 subnets

close ×
#networkhost rangebroadcast
110.6.200.0/2710.6.200.1 – 10.6.200.3010.6.200.31
210.6.200.32/2710.6.200.33 – 10.6.200.6210.6.200.63
310.6.200.64/2710.6.200.65 – 10.6.200.9410.6.200.95
410.6.200.96/2710.6.200.97 – 10.6.200.12610.6.200.127
510.6.200.128/2710.6.200.129 – 10.6.200.15810.6.200.159
610.6.200.160/2710.6.200.161 – 10.6.200.19010.6.200.191
710.6.200.192/2710.6.200.193 – 10.6.200.22210.6.200.223
810.6.200.224/2710.6.200.225 – 10.6.200.25410.6.200.255
910.6.201.0/2710.6.201.1 – 10.6.201.3010.6.201.31
1010.6.201.32/2710.6.201.33 – 10.6.201.6210.6.201.63
1110.6.201.64/2710.6.201.65 – 10.6.201.9410.6.201.95
1210.6.201.96/2710.6.201.97 – 10.6.201.12610.6.201.127
1310.6.201.128/2710.6.201.129 – 10.6.201.15810.6.201.159
1410.6.201.160/2710.6.201.161 – 10.6.201.19010.6.201.191
1510.6.201.192/2710.6.201.193 – 10.6.201.22210.6.201.223
1610.6.201.224/2710.6.201.225 – 10.6.201.25410.6.201.255
1710.6.202.0/2710.6.202.1 – 10.6.202.3010.6.202.31
1810.6.202.32/2710.6.202.33 – 10.6.202.6210.6.202.63
1910.6.202.64/2710.6.202.65 – 10.6.202.9410.6.202.95
2010.6.202.96/2710.6.202.97 – 10.6.202.12610.6.202.127
2110.6.202.128/2710.6.202.129 – 10.6.202.15810.6.202.159
2210.6.202.160/2710.6.202.161 – 10.6.202.19010.6.202.191
2310.6.202.192/2710.6.202.193 – 10.6.202.22210.6.202.223
2410.6.202.224/2710.6.202.225 – 10.6.202.25410.6.202.255
2510.6.203.0/2710.6.203.1 – 10.6.203.3010.6.203.31
2610.6.203.32/2710.6.203.33 – 10.6.203.6210.6.203.63
2710.6.203.64/2710.6.203.65 – 10.6.203.9410.6.203.95
2810.6.203.96/2710.6.203.97 – 10.6.203.12610.6.203.127
2910.6.203.128/2710.6.203.129 – 10.6.203.15810.6.203.159
3010.6.203.160/2710.6.203.161 – 10.6.203.19010.6.203.191
3110.6.203.192/2710.6.203.193 – 10.6.203.22210.6.203.223
3210.6.203.224/2710.6.203.225 – 10.6.203.25410.6.203.255
3310.6.204.0/2710.6.204.1 – 10.6.204.3010.6.204.31
3410.6.204.32/2710.6.204.33 – 10.6.204.6210.6.204.63
3510.6.204.64/2710.6.204.65 – 10.6.204.9410.6.204.95
3610.6.204.96/2710.6.204.97 – 10.6.204.12610.6.204.127
3710.6.204.128/2710.6.204.129 – 10.6.204.15810.6.204.159
3810.6.204.160/2710.6.204.161 – 10.6.204.19010.6.204.191
3910.6.204.192/2710.6.204.193 – 10.6.204.22210.6.204.223
4010.6.204.224/2710.6.204.225 – 10.6.204.25410.6.204.255
4110.6.205.0/2710.6.205.1 – 10.6.205.3010.6.205.31
4210.6.205.32/2710.6.205.33 – 10.6.205.6210.6.205.63
4310.6.205.64/2710.6.205.65 – 10.6.205.9410.6.205.95
4410.6.205.96/2710.6.205.97 – 10.6.205.12610.6.205.127
4510.6.205.128/2710.6.205.129 – 10.6.205.15810.6.205.159
4610.6.205.160/2710.6.205.161 – 10.6.205.19010.6.205.191
4710.6.205.192/2710.6.205.193 – 10.6.205.22210.6.205.223
4810.6.205.224/2710.6.205.225 – 10.6.205.25410.6.205.255
4910.6.206.0/2710.6.206.1 – 10.6.206.3010.6.206.31
5010.6.206.32/2710.6.206.33 – 10.6.206.6210.6.206.63
5110.6.206.64/2710.6.206.65 – 10.6.206.9410.6.206.95
5210.6.206.96/2710.6.206.97 – 10.6.206.12610.6.206.127
5310.6.206.128/2710.6.206.129 – 10.6.206.15810.6.206.159
5410.6.206.160/2710.6.206.161 – 10.6.206.19010.6.206.191
5510.6.206.192/2710.6.206.193 – 10.6.206.22210.6.206.223
5610.6.206.224/2710.6.206.225 – 10.6.206.25410.6.206.255
5710.6.207.0/2710.6.207.1 – 10.6.207.3010.6.207.31
5810.6.207.32/2710.6.207.33 – 10.6.207.6210.6.207.63
5910.6.207.64/2710.6.207.65 – 10.6.207.9410.6.207.95
6010.6.207.96/2710.6.207.97 – 10.6.207.12610.6.207.127
6110.6.207.128/2710.6.207.129 – 10.6.207.15810.6.207.159
6210.6.207.160/2710.6.207.161 – 10.6.207.19010.6.207.191
6310.6.207.192/2710.6.207.193 – 10.6.207.22210.6.207.223
6410.6.207.224/2710.6.207.225 – 10.6.207.25410.6.207.255
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 →