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)10.15.16.0/20
network10.15.16.0/20
broadcast10.15.31.255
first host10.15.16.1
last host10.15.31.254
subnet mask255.255.240.0
wildcard0.0.15.255
addresses4,096
usable hosts4,094
classA
ipcalc 10.15.16.0/20
address00001010.00001111.00010000.00000000
subnet mask11111111.11111111.11110000.00000000
network00001010.00001111.00010000.00000000
broadcast00001010.00001111.00011111.11111111
green = network part, grey = host part
hex0x0a0f1000
decimal168759296
reverse dns0.16.15.10.in-addr.arpa
ipv4-mapped::ffff:a0f:1000

/20 split into /25 · 32 subnets

close ×
#networkhost rangebroadcast
110.15.16.0/2510.15.16.1 – 10.15.16.12610.15.16.127
210.15.16.128/2510.15.16.129 – 10.15.16.25410.15.16.255
310.15.17.0/2510.15.17.1 – 10.15.17.12610.15.17.127
410.15.17.128/2510.15.17.129 – 10.15.17.25410.15.17.255
510.15.18.0/2510.15.18.1 – 10.15.18.12610.15.18.127
610.15.18.128/2510.15.18.129 – 10.15.18.25410.15.18.255
710.15.19.0/2510.15.19.1 – 10.15.19.12610.15.19.127
810.15.19.128/2510.15.19.129 – 10.15.19.25410.15.19.255
910.15.20.0/2510.15.20.1 – 10.15.20.12610.15.20.127
1010.15.20.128/2510.15.20.129 – 10.15.20.25410.15.20.255
1110.15.21.0/2510.15.21.1 – 10.15.21.12610.15.21.127
1210.15.21.128/2510.15.21.129 – 10.15.21.25410.15.21.255
1310.15.22.0/2510.15.22.1 – 10.15.22.12610.15.22.127
1410.15.22.128/2510.15.22.129 – 10.15.22.25410.15.22.255
1510.15.23.0/2510.15.23.1 – 10.15.23.12610.15.23.127
1610.15.23.128/2510.15.23.129 – 10.15.23.25410.15.23.255
1710.15.24.0/2510.15.24.1 – 10.15.24.12610.15.24.127
1810.15.24.128/2510.15.24.129 – 10.15.24.25410.15.24.255
1910.15.25.0/2510.15.25.1 – 10.15.25.12610.15.25.127
2010.15.25.128/2510.15.25.129 – 10.15.25.25410.15.25.255
2110.15.26.0/2510.15.26.1 – 10.15.26.12610.15.26.127
2210.15.26.128/2510.15.26.129 – 10.15.26.25410.15.26.255
2310.15.27.0/2510.15.27.1 – 10.15.27.12610.15.27.127
2410.15.27.128/2510.15.27.129 – 10.15.27.25410.15.27.255
2510.15.28.0/2510.15.28.1 – 10.15.28.12610.15.28.127
2610.15.28.128/2510.15.28.129 – 10.15.28.25410.15.28.255
2710.15.29.0/2510.15.29.1 – 10.15.29.12610.15.29.127
2810.15.29.128/2510.15.29.129 – 10.15.29.25410.15.29.255
2910.15.30.0/2510.15.30.1 – 10.15.30.12610.15.30.127
3010.15.30.128/2510.15.30.129 – 10.15.30.25410.15.30.255
3110.15.31.0/2510.15.31.1 – 10.15.31.12610.15.31.127
3210.15.31.128/2510.15.31.129 – 10.15.31.25410.15.31.255
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 →