ip
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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)10.81.128.0/17
network10.81.128.0/17
broadcast10.81.255.255
first host10.81.128.1
last host10.81.255.254
subnet mask255.255.128.0
wildcard0.0.127.255
addresses32,768
usable hosts32,766
classA
ipcalc 10.81.128.0/17
address00001010.01010001.10000000.00000000
subnet mask11111111.11111111.10000000.00000000
network00001010.01010001.10000000.00000000
broadcast00001010.01010001.11111111.11111111
green = network part, grey = host part
hex0x0a518000
decimal173113344
reverse dns0.128.81.10.in-addr.arpa
ipv4-mapped::ffff:a51:8000

/17 split into /22 · 32 subnets

close ×
#networkhost rangebroadcast
110.81.128.0/2210.81.128.1 – 10.81.131.25410.81.131.255
210.81.132.0/2210.81.132.1 – 10.81.135.25410.81.135.255
310.81.136.0/2210.81.136.1 – 10.81.139.25410.81.139.255
410.81.140.0/2210.81.140.1 – 10.81.143.25410.81.143.255
510.81.144.0/2210.81.144.1 – 10.81.147.25410.81.147.255
610.81.148.0/2210.81.148.1 – 10.81.151.25410.81.151.255
710.81.152.0/2210.81.152.1 – 10.81.155.25410.81.155.255
810.81.156.0/2210.81.156.1 – 10.81.159.25410.81.159.255
910.81.160.0/2210.81.160.1 – 10.81.163.25410.81.163.255
1010.81.164.0/2210.81.164.1 – 10.81.167.25410.81.167.255
1110.81.168.0/2210.81.168.1 – 10.81.171.25410.81.171.255
1210.81.172.0/2210.81.172.1 – 10.81.175.25410.81.175.255
1310.81.176.0/2210.81.176.1 – 10.81.179.25410.81.179.255
1410.81.180.0/2210.81.180.1 – 10.81.183.25410.81.183.255
1510.81.184.0/2210.81.184.1 – 10.81.187.25410.81.187.255
1610.81.188.0/2210.81.188.1 – 10.81.191.25410.81.191.255
1710.81.192.0/2210.81.192.1 – 10.81.195.25410.81.195.255
1810.81.196.0/2210.81.196.1 – 10.81.199.25410.81.199.255
1910.81.200.0/2210.81.200.1 – 10.81.203.25410.81.203.255
2010.81.204.0/2210.81.204.1 – 10.81.207.25410.81.207.255
2110.81.208.0/2210.81.208.1 – 10.81.211.25410.81.211.255
2210.81.212.0/2210.81.212.1 – 10.81.215.25410.81.215.255
2310.81.216.0/2210.81.216.1 – 10.81.219.25410.81.219.255
2410.81.220.0/2210.81.220.1 – 10.81.223.25410.81.223.255
2510.81.224.0/2210.81.224.1 – 10.81.227.25410.81.227.255
2610.81.228.0/2210.81.228.1 – 10.81.231.25410.81.231.255
2710.81.232.0/2210.81.232.1 – 10.81.235.25410.81.235.255
2810.81.236.0/2210.81.236.1 – 10.81.239.25410.81.239.255
2910.81.240.0/2210.81.240.1 – 10.81.243.25410.81.243.255
3010.81.244.0/2210.81.244.1 – 10.81.247.25410.81.247.255
3110.81.248.0/2210.81.248.1 – 10.81.251.25410.81.251.255
3210.81.252.0/2210.81.252.1 – 10.81.255.25410.81.255.255
01 / table

IPv4 CIDR prefix table.

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

prefixsubnet maskaddresseshostsin your /17
/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-
/17255.255.128.032,76832,7661
/18255.255.192.016,38416,3822 split →
/19255.255.224.08,1928,1904 split →
/20255.255.240.04,0964,0948 split →
/21255.255.248.02,0482,04616 split →
/22255.255.252.01,0241,02232 split →
/23255.255.254.051251064 split →
/24255.255.255.0256254128 split →
/25255.255.255.128128126256 split →
/26255.255.255.1926462512 split →
/27255.255.255.22432301,024 split →
/28255.255.255.24016142,048 split →
/29255.255.255.248864,096 split →
/30255.255.255.252428,192 split →
/31255.255.255.2542216,384 split →
/32255.255.255.2551132,768 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 →