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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)10.12.208.0/20
network10.12.208.0/20
broadcast10.12.223.255
first host10.12.208.1
last host10.12.223.254
subnet mask255.255.240.0
wildcard0.0.15.255
addresses4,096
usable hosts4,094
classA
ipcalc 10.12.208.0/20
address00001010.00001100.11010000.00000000
subnet mask11111111.11111111.11110000.00000000
network00001010.00001100.11010000.00000000
broadcast00001010.00001100.11011111.11111111
green = network part, grey = host part
hex0x0a0cd000
decimal168611840
reverse dns0.208.12.10.in-addr.arpa
ipv4-mapped::ffff:a0c:d000

/20 split into /25 · 32 subnets

close ×
#networkhost rangebroadcast
110.12.208.0/2510.12.208.1 – 10.12.208.12610.12.208.127
210.12.208.128/2510.12.208.129 – 10.12.208.25410.12.208.255
310.12.209.0/2510.12.209.1 – 10.12.209.12610.12.209.127
410.12.209.128/2510.12.209.129 – 10.12.209.25410.12.209.255
510.12.210.0/2510.12.210.1 – 10.12.210.12610.12.210.127
610.12.210.128/2510.12.210.129 – 10.12.210.25410.12.210.255
710.12.211.0/2510.12.211.1 – 10.12.211.12610.12.211.127
810.12.211.128/2510.12.211.129 – 10.12.211.25410.12.211.255
910.12.212.0/2510.12.212.1 – 10.12.212.12610.12.212.127
1010.12.212.128/2510.12.212.129 – 10.12.212.25410.12.212.255
1110.12.213.0/2510.12.213.1 – 10.12.213.12610.12.213.127
1210.12.213.128/2510.12.213.129 – 10.12.213.25410.12.213.255
1310.12.214.0/2510.12.214.1 – 10.12.214.12610.12.214.127
1410.12.214.128/2510.12.214.129 – 10.12.214.25410.12.214.255
1510.12.215.0/2510.12.215.1 – 10.12.215.12610.12.215.127
1610.12.215.128/2510.12.215.129 – 10.12.215.25410.12.215.255
1710.12.216.0/2510.12.216.1 – 10.12.216.12610.12.216.127
1810.12.216.128/2510.12.216.129 – 10.12.216.25410.12.216.255
1910.12.217.0/2510.12.217.1 – 10.12.217.12610.12.217.127
2010.12.217.128/2510.12.217.129 – 10.12.217.25410.12.217.255
2110.12.218.0/2510.12.218.1 – 10.12.218.12610.12.218.127
2210.12.218.128/2510.12.218.129 – 10.12.218.25410.12.218.255
2310.12.219.0/2510.12.219.1 – 10.12.219.12610.12.219.127
2410.12.219.128/2510.12.219.129 – 10.12.219.25410.12.219.255
2510.12.220.0/2510.12.220.1 – 10.12.220.12610.12.220.127
2610.12.220.128/2510.12.220.129 – 10.12.220.25410.12.220.255
2710.12.221.0/2510.12.221.1 – 10.12.221.12610.12.221.127
2810.12.221.128/2510.12.221.129 – 10.12.221.25410.12.221.255
2910.12.222.0/2510.12.222.1 – 10.12.222.12610.12.222.127
3010.12.222.128/2510.12.222.129 – 10.12.222.25410.12.222.255
3110.12.223.0/2510.12.223.1 – 10.12.223.12610.12.223.127
3210.12.223.128/2510.12.223.129 – 10.12.223.25410.12.223.255
01 / table

IPv4 CIDR prefix table.

Click a prefix longer than your network to split it into subnets.

prefixsubnet maskaddresseshostsin your /20
/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-
/20255.255.240.04,0964,0941
/21255.255.248.02,0482,0462 split →
/22255.255.252.01,0241,0224 split →
/23255.255.254.05125108 split →
/24255.255.255.025625416 split →
/25255.255.255.12812812632 split →
/26255.255.255.192646264 split →
/27255.255.255.2243230128 split →
/28255.255.255.2401614256 split →
/29255.255.255.24886512 split →
/30255.255.255.252421,024 split →
/31255.255.255.254222,048 split →
/32255.255.255.255114,096 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 →