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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)10.7.240.0/21
network10.7.240.0/21
broadcast10.7.247.255
first host10.7.240.1
last host10.7.247.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.7.240.0/21
address00001010.00000111.11110000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000111.11110000.00000000
broadcast00001010.00000111.11110111.11111111
green = network part, grey = host part
hex0x0a07f000
decimal168292352
reverse dns0.240.7.10.in-addr.arpa
ipv4-mapped::ffff:a07:f000

/21 split into /27 · 64 subnets

close ×
#networkhost rangebroadcast
110.7.240.0/2710.7.240.1 – 10.7.240.3010.7.240.31
210.7.240.32/2710.7.240.33 – 10.7.240.6210.7.240.63
310.7.240.64/2710.7.240.65 – 10.7.240.9410.7.240.95
410.7.240.96/2710.7.240.97 – 10.7.240.12610.7.240.127
510.7.240.128/2710.7.240.129 – 10.7.240.15810.7.240.159
610.7.240.160/2710.7.240.161 – 10.7.240.19010.7.240.191
710.7.240.192/2710.7.240.193 – 10.7.240.22210.7.240.223
810.7.240.224/2710.7.240.225 – 10.7.240.25410.7.240.255
910.7.241.0/2710.7.241.1 – 10.7.241.3010.7.241.31
1010.7.241.32/2710.7.241.33 – 10.7.241.6210.7.241.63
1110.7.241.64/2710.7.241.65 – 10.7.241.9410.7.241.95
1210.7.241.96/2710.7.241.97 – 10.7.241.12610.7.241.127
1310.7.241.128/2710.7.241.129 – 10.7.241.15810.7.241.159
1410.7.241.160/2710.7.241.161 – 10.7.241.19010.7.241.191
1510.7.241.192/2710.7.241.193 – 10.7.241.22210.7.241.223
1610.7.241.224/2710.7.241.225 – 10.7.241.25410.7.241.255
1710.7.242.0/2710.7.242.1 – 10.7.242.3010.7.242.31
1810.7.242.32/2710.7.242.33 – 10.7.242.6210.7.242.63
1910.7.242.64/2710.7.242.65 – 10.7.242.9410.7.242.95
2010.7.242.96/2710.7.242.97 – 10.7.242.12610.7.242.127
2110.7.242.128/2710.7.242.129 – 10.7.242.15810.7.242.159
2210.7.242.160/2710.7.242.161 – 10.7.242.19010.7.242.191
2310.7.242.192/2710.7.242.193 – 10.7.242.22210.7.242.223
2410.7.242.224/2710.7.242.225 – 10.7.242.25410.7.242.255
2510.7.243.0/2710.7.243.1 – 10.7.243.3010.7.243.31
2610.7.243.32/2710.7.243.33 – 10.7.243.6210.7.243.63
2710.7.243.64/2710.7.243.65 – 10.7.243.9410.7.243.95
2810.7.243.96/2710.7.243.97 – 10.7.243.12610.7.243.127
2910.7.243.128/2710.7.243.129 – 10.7.243.15810.7.243.159
3010.7.243.160/2710.7.243.161 – 10.7.243.19010.7.243.191
3110.7.243.192/2710.7.243.193 – 10.7.243.22210.7.243.223
3210.7.243.224/2710.7.243.225 – 10.7.243.25410.7.243.255
3310.7.244.0/2710.7.244.1 – 10.7.244.3010.7.244.31
3410.7.244.32/2710.7.244.33 – 10.7.244.6210.7.244.63
3510.7.244.64/2710.7.244.65 – 10.7.244.9410.7.244.95
3610.7.244.96/2710.7.244.97 – 10.7.244.12610.7.244.127
3710.7.244.128/2710.7.244.129 – 10.7.244.15810.7.244.159
3810.7.244.160/2710.7.244.161 – 10.7.244.19010.7.244.191
3910.7.244.192/2710.7.244.193 – 10.7.244.22210.7.244.223
4010.7.244.224/2710.7.244.225 – 10.7.244.25410.7.244.255
4110.7.245.0/2710.7.245.1 – 10.7.245.3010.7.245.31
4210.7.245.32/2710.7.245.33 – 10.7.245.6210.7.245.63
4310.7.245.64/2710.7.245.65 – 10.7.245.9410.7.245.95
4410.7.245.96/2710.7.245.97 – 10.7.245.12610.7.245.127
4510.7.245.128/2710.7.245.129 – 10.7.245.15810.7.245.159
4610.7.245.160/2710.7.245.161 – 10.7.245.19010.7.245.191
4710.7.245.192/2710.7.245.193 – 10.7.245.22210.7.245.223
4810.7.245.224/2710.7.245.225 – 10.7.245.25410.7.245.255
4910.7.246.0/2710.7.246.1 – 10.7.246.3010.7.246.31
5010.7.246.32/2710.7.246.33 – 10.7.246.6210.7.246.63
5110.7.246.64/2710.7.246.65 – 10.7.246.9410.7.246.95
5210.7.246.96/2710.7.246.97 – 10.7.246.12610.7.246.127
5310.7.246.128/2710.7.246.129 – 10.7.246.15810.7.246.159
5410.7.246.160/2710.7.246.161 – 10.7.246.19010.7.246.191
5510.7.246.192/2710.7.246.193 – 10.7.246.22210.7.246.223
5610.7.246.224/2710.7.246.225 – 10.7.246.25410.7.246.255
5710.7.247.0/2710.7.247.1 – 10.7.247.3010.7.247.31
5810.7.247.32/2710.7.247.33 – 10.7.247.6210.7.247.63
5910.7.247.64/2710.7.247.65 – 10.7.247.9410.7.247.95
6010.7.247.96/2710.7.247.97 – 10.7.247.12610.7.247.127
6110.7.247.128/2710.7.247.129 – 10.7.247.15810.7.247.159
6210.7.247.160/2710.7.247.161 – 10.7.247.19010.7.247.191
6310.7.247.192/2710.7.247.193 – 10.7.247.22210.7.247.223
6410.7.247.224/2710.7.247.225 – 10.7.247.25410.7.247.255
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 →