ip
ipku.in

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)10.10.128.0/20
network10.10.128.0/20
broadcast10.10.143.255
first host10.10.128.1
last host10.10.143.254
subnet mask255.255.240.0
wildcard0.0.15.255
addresses4,096
usable hosts4,094
classA
ipcalc 10.10.128.0/20
address00001010.00001010.10000000.00000000
subnet mask11111111.11111111.11110000.00000000
network00001010.00001010.10000000.00000000
broadcast00001010.00001010.10001111.11111111
green = network part, grey = host part
hex0x0a0a8000
decimal168460288
reverse dns0.128.10.10.in-addr.arpa
ipv4-mapped::ffff:a0a:8000

/20 split into /25 · 32 subnets

close ×
#networkhost rangebroadcast
110.10.128.0/2510.10.128.1 – 10.10.128.12610.10.128.127
210.10.128.128/2510.10.128.129 – 10.10.128.25410.10.128.255
310.10.129.0/2510.10.129.1 – 10.10.129.12610.10.129.127
410.10.129.128/2510.10.129.129 – 10.10.129.25410.10.129.255
510.10.130.0/2510.10.130.1 – 10.10.130.12610.10.130.127
610.10.130.128/2510.10.130.129 – 10.10.130.25410.10.130.255
710.10.131.0/2510.10.131.1 – 10.10.131.12610.10.131.127
810.10.131.128/2510.10.131.129 – 10.10.131.25410.10.131.255
910.10.132.0/2510.10.132.1 – 10.10.132.12610.10.132.127
1010.10.132.128/2510.10.132.129 – 10.10.132.25410.10.132.255
1110.10.133.0/2510.10.133.1 – 10.10.133.12610.10.133.127
1210.10.133.128/2510.10.133.129 – 10.10.133.25410.10.133.255
1310.10.134.0/2510.10.134.1 – 10.10.134.12610.10.134.127
1410.10.134.128/2510.10.134.129 – 10.10.134.25410.10.134.255
1510.10.135.0/2510.10.135.1 – 10.10.135.12610.10.135.127
1610.10.135.128/2510.10.135.129 – 10.10.135.25410.10.135.255
1710.10.136.0/2510.10.136.1 – 10.10.136.12610.10.136.127
1810.10.136.128/2510.10.136.129 – 10.10.136.25410.10.136.255
1910.10.137.0/2510.10.137.1 – 10.10.137.12610.10.137.127
2010.10.137.128/2510.10.137.129 – 10.10.137.25410.10.137.255
2110.10.138.0/2510.10.138.1 – 10.10.138.12610.10.138.127
2210.10.138.128/2510.10.138.129 – 10.10.138.25410.10.138.255
2310.10.139.0/2510.10.139.1 – 10.10.139.12610.10.139.127
2410.10.139.128/2510.10.139.129 – 10.10.139.25410.10.139.255
2510.10.140.0/2510.10.140.1 – 10.10.140.12610.10.140.127
2610.10.140.128/2510.10.140.129 – 10.10.140.25410.10.140.255
2710.10.141.0/2510.10.141.1 – 10.10.141.12610.10.141.127
2810.10.141.128/2510.10.141.129 – 10.10.141.25410.10.141.255
2910.10.142.0/2510.10.142.1 – 10.10.142.12610.10.142.127
3010.10.142.128/2510.10.142.129 – 10.10.142.25410.10.142.255
3110.10.143.0/2510.10.143.1 – 10.10.143.12610.10.143.127
3210.10.143.128/2510.10.143.129 – 10.10.143.25410.10.143.255
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 →