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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)10.21.64.0/19
network10.21.64.0/19
broadcast10.21.95.255
first host10.21.64.1
last host10.21.95.254
subnet mask255.255.224.0
wildcard0.0.31.255
addresses8,192
usable hosts8,190
classA
ipcalc 10.21.64.0/19
address00001010.00010101.01000000.00000000
subnet mask11111111.11111111.11100000.00000000
network00001010.00010101.01000000.00000000
broadcast00001010.00010101.01011111.11111111
green = network part, grey = host part
hex0x0a154000
decimal169164800
reverse dns0.64.21.10.in-addr.arpa
ipv4-mapped::ffff:a15:4000

/19 split into /25 · 64 subnets

close ×
#networkhost rangebroadcast
110.21.64.0/2510.21.64.1 – 10.21.64.12610.21.64.127
210.21.64.128/2510.21.64.129 – 10.21.64.25410.21.64.255
310.21.65.0/2510.21.65.1 – 10.21.65.12610.21.65.127
410.21.65.128/2510.21.65.129 – 10.21.65.25410.21.65.255
510.21.66.0/2510.21.66.1 – 10.21.66.12610.21.66.127
610.21.66.128/2510.21.66.129 – 10.21.66.25410.21.66.255
710.21.67.0/2510.21.67.1 – 10.21.67.12610.21.67.127
810.21.67.128/2510.21.67.129 – 10.21.67.25410.21.67.255
910.21.68.0/2510.21.68.1 – 10.21.68.12610.21.68.127
1010.21.68.128/2510.21.68.129 – 10.21.68.25410.21.68.255
1110.21.69.0/2510.21.69.1 – 10.21.69.12610.21.69.127
1210.21.69.128/2510.21.69.129 – 10.21.69.25410.21.69.255
1310.21.70.0/2510.21.70.1 – 10.21.70.12610.21.70.127
1410.21.70.128/2510.21.70.129 – 10.21.70.25410.21.70.255
1510.21.71.0/2510.21.71.1 – 10.21.71.12610.21.71.127
1610.21.71.128/2510.21.71.129 – 10.21.71.25410.21.71.255
1710.21.72.0/2510.21.72.1 – 10.21.72.12610.21.72.127
1810.21.72.128/2510.21.72.129 – 10.21.72.25410.21.72.255
1910.21.73.0/2510.21.73.1 – 10.21.73.12610.21.73.127
2010.21.73.128/2510.21.73.129 – 10.21.73.25410.21.73.255
2110.21.74.0/2510.21.74.1 – 10.21.74.12610.21.74.127
2210.21.74.128/2510.21.74.129 – 10.21.74.25410.21.74.255
2310.21.75.0/2510.21.75.1 – 10.21.75.12610.21.75.127
2410.21.75.128/2510.21.75.129 – 10.21.75.25410.21.75.255
2510.21.76.0/2510.21.76.1 – 10.21.76.12610.21.76.127
2610.21.76.128/2510.21.76.129 – 10.21.76.25410.21.76.255
2710.21.77.0/2510.21.77.1 – 10.21.77.12610.21.77.127
2810.21.77.128/2510.21.77.129 – 10.21.77.25410.21.77.255
2910.21.78.0/2510.21.78.1 – 10.21.78.12610.21.78.127
3010.21.78.128/2510.21.78.129 – 10.21.78.25410.21.78.255
3110.21.79.0/2510.21.79.1 – 10.21.79.12610.21.79.127
3210.21.79.128/2510.21.79.129 – 10.21.79.25410.21.79.255
3310.21.80.0/2510.21.80.1 – 10.21.80.12610.21.80.127
3410.21.80.128/2510.21.80.129 – 10.21.80.25410.21.80.255
3510.21.81.0/2510.21.81.1 – 10.21.81.12610.21.81.127
3610.21.81.128/2510.21.81.129 – 10.21.81.25410.21.81.255
3710.21.82.0/2510.21.82.1 – 10.21.82.12610.21.82.127
3810.21.82.128/2510.21.82.129 – 10.21.82.25410.21.82.255
3910.21.83.0/2510.21.83.1 – 10.21.83.12610.21.83.127
4010.21.83.128/2510.21.83.129 – 10.21.83.25410.21.83.255
4110.21.84.0/2510.21.84.1 – 10.21.84.12610.21.84.127
4210.21.84.128/2510.21.84.129 – 10.21.84.25410.21.84.255
4310.21.85.0/2510.21.85.1 – 10.21.85.12610.21.85.127
4410.21.85.128/2510.21.85.129 – 10.21.85.25410.21.85.255
4510.21.86.0/2510.21.86.1 – 10.21.86.12610.21.86.127
4610.21.86.128/2510.21.86.129 – 10.21.86.25410.21.86.255
4710.21.87.0/2510.21.87.1 – 10.21.87.12610.21.87.127
4810.21.87.128/2510.21.87.129 – 10.21.87.25410.21.87.255
4910.21.88.0/2510.21.88.1 – 10.21.88.12610.21.88.127
5010.21.88.128/2510.21.88.129 – 10.21.88.25410.21.88.255
5110.21.89.0/2510.21.89.1 – 10.21.89.12610.21.89.127
5210.21.89.128/2510.21.89.129 – 10.21.89.25410.21.89.255
5310.21.90.0/2510.21.90.1 – 10.21.90.12610.21.90.127
5410.21.90.128/2510.21.90.129 – 10.21.90.25410.21.90.255
5510.21.91.0/2510.21.91.1 – 10.21.91.12610.21.91.127
5610.21.91.128/2510.21.91.129 – 10.21.91.25410.21.91.255
5710.21.92.0/2510.21.92.1 – 10.21.92.12610.21.92.127
5810.21.92.128/2510.21.92.129 – 10.21.92.25410.21.92.255
5910.21.93.0/2510.21.93.1 – 10.21.93.12610.21.93.127
6010.21.93.128/2510.21.93.129 – 10.21.93.25410.21.93.255
6110.21.94.0/2510.21.94.1 – 10.21.94.12610.21.94.127
6210.21.94.128/2510.21.94.129 – 10.21.94.25410.21.94.255
6310.21.95.0/2510.21.95.1 – 10.21.95.12610.21.95.127
6410.21.95.128/2510.21.95.129 – 10.21.95.25410.21.95.255
01 / table

IPv4 CIDR prefix table.

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

prefixsubnet maskaddresseshostsin your /19
/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-
/19255.255.224.08,1928,1901
/20255.255.240.04,0964,0942 split →
/21255.255.248.02,0482,0464 split →
/22255.255.252.01,0241,0228 split →
/23255.255.254.051251016 split →
/24255.255.255.025625432 split →
/25255.255.255.12812812664 split →
/26255.255.255.1926462128 split →
/27255.255.255.2243230256 split →
/28255.255.255.2401614512 split →
/29255.255.255.248861,024 split →
/30255.255.255.252422,048 split →
/31255.255.255.254224,096 split →
/32255.255.255.255118,192 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 →