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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)10.37.64.0/20
network10.37.64.0/20
broadcast10.37.79.255
first host10.37.64.1
last host10.37.79.254
subnet mask255.255.240.0
wildcard0.0.15.255
addresses4,096
usable hosts4,094
classA
ipcalc 10.37.64.0/20
address00001010.00100101.01000000.00000000
subnet mask11111111.11111111.11110000.00000000
network00001010.00100101.01000000.00000000
broadcast00001010.00100101.01001111.11111111
green = network part, grey = host part
hex0x0a254000
decimal170213376
reverse dns0.64.37.10.in-addr.arpa
ipv4-mapped::ffff:a25:4000

/20 split into /25 · 32 subnets

close ×
#networkhost rangebroadcast
110.37.64.0/2510.37.64.1 – 10.37.64.12610.37.64.127
210.37.64.128/2510.37.64.129 – 10.37.64.25410.37.64.255
310.37.65.0/2510.37.65.1 – 10.37.65.12610.37.65.127
410.37.65.128/2510.37.65.129 – 10.37.65.25410.37.65.255
510.37.66.0/2510.37.66.1 – 10.37.66.12610.37.66.127
610.37.66.128/2510.37.66.129 – 10.37.66.25410.37.66.255
710.37.67.0/2510.37.67.1 – 10.37.67.12610.37.67.127
810.37.67.128/2510.37.67.129 – 10.37.67.25410.37.67.255
910.37.68.0/2510.37.68.1 – 10.37.68.12610.37.68.127
1010.37.68.128/2510.37.68.129 – 10.37.68.25410.37.68.255
1110.37.69.0/2510.37.69.1 – 10.37.69.12610.37.69.127
1210.37.69.128/2510.37.69.129 – 10.37.69.25410.37.69.255
1310.37.70.0/2510.37.70.1 – 10.37.70.12610.37.70.127
1410.37.70.128/2510.37.70.129 – 10.37.70.25410.37.70.255
1510.37.71.0/2510.37.71.1 – 10.37.71.12610.37.71.127
1610.37.71.128/2510.37.71.129 – 10.37.71.25410.37.71.255
1710.37.72.0/2510.37.72.1 – 10.37.72.12610.37.72.127
1810.37.72.128/2510.37.72.129 – 10.37.72.25410.37.72.255
1910.37.73.0/2510.37.73.1 – 10.37.73.12610.37.73.127
2010.37.73.128/2510.37.73.129 – 10.37.73.25410.37.73.255
2110.37.74.0/2510.37.74.1 – 10.37.74.12610.37.74.127
2210.37.74.128/2510.37.74.129 – 10.37.74.25410.37.74.255
2310.37.75.0/2510.37.75.1 – 10.37.75.12610.37.75.127
2410.37.75.128/2510.37.75.129 – 10.37.75.25410.37.75.255
2510.37.76.0/2510.37.76.1 – 10.37.76.12610.37.76.127
2610.37.76.128/2510.37.76.129 – 10.37.76.25410.37.76.255
2710.37.77.0/2510.37.77.1 – 10.37.77.12610.37.77.127
2810.37.77.128/2510.37.77.129 – 10.37.77.25410.37.77.255
2910.37.78.0/2510.37.78.1 – 10.37.78.12610.37.78.127
3010.37.78.128/2510.37.78.129 – 10.37.78.25410.37.78.255
3110.37.79.0/2510.37.79.1 – 10.37.79.12610.37.79.127
3210.37.79.128/2510.37.79.129 – 10.37.79.25410.37.79.255
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 →