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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)10.7.208.0/21
network10.7.208.0/21
broadcast10.7.215.255
first host10.7.208.1
last host10.7.215.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.7.208.0/21
address00001010.00000111.11010000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000111.11010000.00000000
broadcast00001010.00000111.11010111.11111111
green = network part, grey = host part
hex0x0a07d000
decimal168284160
reverse dns0.208.7.10.in-addr.arpa
ipv4-mapped::ffff:a07:d000

/21 split into /26 · 32 subnets

close ×
#networkhost rangebroadcast
110.7.208.0/2610.7.208.1 – 10.7.208.6210.7.208.63
210.7.208.64/2610.7.208.65 – 10.7.208.12610.7.208.127
310.7.208.128/2610.7.208.129 – 10.7.208.19010.7.208.191
410.7.208.192/2610.7.208.193 – 10.7.208.25410.7.208.255
510.7.209.0/2610.7.209.1 – 10.7.209.6210.7.209.63
610.7.209.64/2610.7.209.65 – 10.7.209.12610.7.209.127
710.7.209.128/2610.7.209.129 – 10.7.209.19010.7.209.191
810.7.209.192/2610.7.209.193 – 10.7.209.25410.7.209.255
910.7.210.0/2610.7.210.1 – 10.7.210.6210.7.210.63
1010.7.210.64/2610.7.210.65 – 10.7.210.12610.7.210.127
1110.7.210.128/2610.7.210.129 – 10.7.210.19010.7.210.191
1210.7.210.192/2610.7.210.193 – 10.7.210.25410.7.210.255
1310.7.211.0/2610.7.211.1 – 10.7.211.6210.7.211.63
1410.7.211.64/2610.7.211.65 – 10.7.211.12610.7.211.127
1510.7.211.128/2610.7.211.129 – 10.7.211.19010.7.211.191
1610.7.211.192/2610.7.211.193 – 10.7.211.25410.7.211.255
1710.7.212.0/2610.7.212.1 – 10.7.212.6210.7.212.63
1810.7.212.64/2610.7.212.65 – 10.7.212.12610.7.212.127
1910.7.212.128/2610.7.212.129 – 10.7.212.19010.7.212.191
2010.7.212.192/2610.7.212.193 – 10.7.212.25410.7.212.255
2110.7.213.0/2610.7.213.1 – 10.7.213.6210.7.213.63
2210.7.213.64/2610.7.213.65 – 10.7.213.12610.7.213.127
2310.7.213.128/2610.7.213.129 – 10.7.213.19010.7.213.191
2410.7.213.192/2610.7.213.193 – 10.7.213.25410.7.213.255
2510.7.214.0/2610.7.214.1 – 10.7.214.6210.7.214.63
2610.7.214.64/2610.7.214.65 – 10.7.214.12610.7.214.127
2710.7.214.128/2610.7.214.129 – 10.7.214.19010.7.214.191
2810.7.214.192/2610.7.214.193 – 10.7.214.25410.7.214.255
2910.7.215.0/2610.7.215.1 – 10.7.215.6210.7.215.63
3010.7.215.64/2610.7.215.65 – 10.7.215.12610.7.215.127
3110.7.215.128/2610.7.215.129 – 10.7.215.19010.7.215.191
3210.7.215.192/2610.7.215.193 – 10.7.215.25410.7.215.255
01 / table

IPv4 CIDR prefix table.

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

prefixsubnet maskaddresseshostsin your /21
/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-
/20255.255.240.04,0964,094-
/21255.255.248.02,0482,0461
/22255.255.252.01,0241,0222 split →
/23255.255.254.05125104 split →
/24255.255.255.02562548 split →
/25255.255.255.12812812616 split →
/26255.255.255.192646232 split →
/27255.255.255.224323064 split →
/28255.255.255.2401614128 split →
/29255.255.255.24886256 split →
/30255.255.255.25242512 split →
/31255.255.255.254221,024 split →
/32255.255.255.255112,048 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 →