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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)10.12.240.0/20
network10.12.240.0/20
broadcast10.12.255.255
first host10.12.240.1
last host10.12.255.254
subnet mask255.255.240.0
wildcard0.0.15.255
addresses4,096
usable hosts4,094
classA
ipcalc 10.12.240.0/20
address00001010.00001100.11110000.00000000
subnet mask11111111.11111111.11110000.00000000
network00001010.00001100.11110000.00000000
broadcast00001010.00001100.11111111.11111111
green = network part, grey = host part
hex0x0a0cf000
decimal168620032
reverse dns0.240.12.10.in-addr.arpa
ipv4-mapped::ffff:a0c:f000

/20 split into /26 · 64 subnets

close ×
#networkhost rangebroadcast
110.12.240.0/2610.12.240.1 – 10.12.240.6210.12.240.63
210.12.240.64/2610.12.240.65 – 10.12.240.12610.12.240.127
310.12.240.128/2610.12.240.129 – 10.12.240.19010.12.240.191
410.12.240.192/2610.12.240.193 – 10.12.240.25410.12.240.255
510.12.241.0/2610.12.241.1 – 10.12.241.6210.12.241.63
610.12.241.64/2610.12.241.65 – 10.12.241.12610.12.241.127
710.12.241.128/2610.12.241.129 – 10.12.241.19010.12.241.191
810.12.241.192/2610.12.241.193 – 10.12.241.25410.12.241.255
910.12.242.0/2610.12.242.1 – 10.12.242.6210.12.242.63
1010.12.242.64/2610.12.242.65 – 10.12.242.12610.12.242.127
1110.12.242.128/2610.12.242.129 – 10.12.242.19010.12.242.191
1210.12.242.192/2610.12.242.193 – 10.12.242.25410.12.242.255
1310.12.243.0/2610.12.243.1 – 10.12.243.6210.12.243.63
1410.12.243.64/2610.12.243.65 – 10.12.243.12610.12.243.127
1510.12.243.128/2610.12.243.129 – 10.12.243.19010.12.243.191
1610.12.243.192/2610.12.243.193 – 10.12.243.25410.12.243.255
1710.12.244.0/2610.12.244.1 – 10.12.244.6210.12.244.63
1810.12.244.64/2610.12.244.65 – 10.12.244.12610.12.244.127
1910.12.244.128/2610.12.244.129 – 10.12.244.19010.12.244.191
2010.12.244.192/2610.12.244.193 – 10.12.244.25410.12.244.255
2110.12.245.0/2610.12.245.1 – 10.12.245.6210.12.245.63
2210.12.245.64/2610.12.245.65 – 10.12.245.12610.12.245.127
2310.12.245.128/2610.12.245.129 – 10.12.245.19010.12.245.191
2410.12.245.192/2610.12.245.193 – 10.12.245.25410.12.245.255
2510.12.246.0/2610.12.246.1 – 10.12.246.6210.12.246.63
2610.12.246.64/2610.12.246.65 – 10.12.246.12610.12.246.127
2710.12.246.128/2610.12.246.129 – 10.12.246.19010.12.246.191
2810.12.246.192/2610.12.246.193 – 10.12.246.25410.12.246.255
2910.12.247.0/2610.12.247.1 – 10.12.247.6210.12.247.63
3010.12.247.64/2610.12.247.65 – 10.12.247.12610.12.247.127
3110.12.247.128/2610.12.247.129 – 10.12.247.19010.12.247.191
3210.12.247.192/2610.12.247.193 – 10.12.247.25410.12.247.255
3310.12.248.0/2610.12.248.1 – 10.12.248.6210.12.248.63
3410.12.248.64/2610.12.248.65 – 10.12.248.12610.12.248.127
3510.12.248.128/2610.12.248.129 – 10.12.248.19010.12.248.191
3610.12.248.192/2610.12.248.193 – 10.12.248.25410.12.248.255
3710.12.249.0/2610.12.249.1 – 10.12.249.6210.12.249.63
3810.12.249.64/2610.12.249.65 – 10.12.249.12610.12.249.127
3910.12.249.128/2610.12.249.129 – 10.12.249.19010.12.249.191
4010.12.249.192/2610.12.249.193 – 10.12.249.25410.12.249.255
4110.12.250.0/2610.12.250.1 – 10.12.250.6210.12.250.63
4210.12.250.64/2610.12.250.65 – 10.12.250.12610.12.250.127
4310.12.250.128/2610.12.250.129 – 10.12.250.19010.12.250.191
4410.12.250.192/2610.12.250.193 – 10.12.250.25410.12.250.255
4510.12.251.0/2610.12.251.1 – 10.12.251.6210.12.251.63
4610.12.251.64/2610.12.251.65 – 10.12.251.12610.12.251.127
4710.12.251.128/2610.12.251.129 – 10.12.251.19010.12.251.191
4810.12.251.192/2610.12.251.193 – 10.12.251.25410.12.251.255
4910.12.252.0/2610.12.252.1 – 10.12.252.6210.12.252.63
5010.12.252.64/2610.12.252.65 – 10.12.252.12610.12.252.127
5110.12.252.128/2610.12.252.129 – 10.12.252.19010.12.252.191
5210.12.252.192/2610.12.252.193 – 10.12.252.25410.12.252.255
5310.12.253.0/2610.12.253.1 – 10.12.253.6210.12.253.63
5410.12.253.64/2610.12.253.65 – 10.12.253.12610.12.253.127
5510.12.253.128/2610.12.253.129 – 10.12.253.19010.12.253.191
5610.12.253.192/2610.12.253.193 – 10.12.253.25410.12.253.255
5710.12.254.0/2610.12.254.1 – 10.12.254.6210.12.254.63
5810.12.254.64/2610.12.254.65 – 10.12.254.12610.12.254.127
5910.12.254.128/2610.12.254.129 – 10.12.254.19010.12.254.191
6010.12.254.192/2610.12.254.193 – 10.12.254.25410.12.254.255
6110.12.255.0/2610.12.255.1 – 10.12.255.6210.12.255.63
6210.12.255.64/2610.12.255.65 – 10.12.255.12610.12.255.127
6310.12.255.128/2610.12.255.129 – 10.12.255.19010.12.255.191
6410.12.255.192/2610.12.255.193 – 10.12.255.25410.12.255.255
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 →