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)10.21.0.0/17
network10.21.0.0/17
broadcast10.21.127.255
first host10.21.0.1
last host10.21.127.254
subnet mask255.255.128.0
wildcard0.0.127.255
addresses32,768
usable hosts32,766
classA
ipcalc 10.21.0.0/17
address00001010.00010101.00000000.00000000
subnet mask11111111.11111111.10000000.00000000
network00001010.00010101.00000000.00000000
broadcast00001010.00010101.01111111.11111111
green = network part, grey = host part
hex0x0a150000
decimal169148416
reverse dns0.0.21.10.in-addr.arpa
ipv4-mapped::ffff:a15:0

/17 split into /22 · 32 subnets

close ×
#networkhost rangebroadcast
110.21.0.0/2210.21.0.1 – 10.21.3.25410.21.3.255
210.21.4.0/2210.21.4.1 – 10.21.7.25410.21.7.255
310.21.8.0/2210.21.8.1 – 10.21.11.25410.21.11.255
410.21.12.0/2210.21.12.1 – 10.21.15.25410.21.15.255
510.21.16.0/2210.21.16.1 – 10.21.19.25410.21.19.255
610.21.20.0/2210.21.20.1 – 10.21.23.25410.21.23.255
710.21.24.0/2210.21.24.1 – 10.21.27.25410.21.27.255
810.21.28.0/2210.21.28.1 – 10.21.31.25410.21.31.255
910.21.32.0/2210.21.32.1 – 10.21.35.25410.21.35.255
1010.21.36.0/2210.21.36.1 – 10.21.39.25410.21.39.255
1110.21.40.0/2210.21.40.1 – 10.21.43.25410.21.43.255
1210.21.44.0/2210.21.44.1 – 10.21.47.25410.21.47.255
1310.21.48.0/2210.21.48.1 – 10.21.51.25410.21.51.255
1410.21.52.0/2210.21.52.1 – 10.21.55.25410.21.55.255
1510.21.56.0/2210.21.56.1 – 10.21.59.25410.21.59.255
1610.21.60.0/2210.21.60.1 – 10.21.63.25410.21.63.255
1710.21.64.0/2210.21.64.1 – 10.21.67.25410.21.67.255
1810.21.68.0/2210.21.68.1 – 10.21.71.25410.21.71.255
1910.21.72.0/2210.21.72.1 – 10.21.75.25410.21.75.255
2010.21.76.0/2210.21.76.1 – 10.21.79.25410.21.79.255
2110.21.80.0/2210.21.80.1 – 10.21.83.25410.21.83.255
2210.21.84.0/2210.21.84.1 – 10.21.87.25410.21.87.255
2310.21.88.0/2210.21.88.1 – 10.21.91.25410.21.91.255
2410.21.92.0/2210.21.92.1 – 10.21.95.25410.21.95.255
2510.21.96.0/2210.21.96.1 – 10.21.99.25410.21.99.255
2610.21.100.0/2210.21.100.1 – 10.21.103.25410.21.103.255
2710.21.104.0/2210.21.104.1 – 10.21.107.25410.21.107.255
2810.21.108.0/2210.21.108.1 – 10.21.111.25410.21.111.255
2910.21.112.0/2210.21.112.1 – 10.21.115.25410.21.115.255
3010.21.116.0/2210.21.116.1 – 10.21.119.25410.21.119.255
3110.21.120.0/2210.21.120.1 – 10.21.123.25410.21.123.255
3210.21.124.0/2210.21.124.1 – 10.21.127.25410.21.127.255
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 →