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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)10.6.176.0/21
network10.6.176.0/21
broadcast10.6.183.255
first host10.6.176.1
last host10.6.183.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.6.176.0/21
address00001010.00000110.10110000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000110.10110000.00000000
broadcast00001010.00000110.10110111.11111111
green = network part, grey = host part
hex0x0a06b000
decimal168210432
reverse dns0.176.6.10.in-addr.arpa
ipv4-mapped::ffff:a06:b000

/21 split into /27 · 64 subnets

close ×
#networkhost rangebroadcast
110.6.176.0/2710.6.176.1 – 10.6.176.3010.6.176.31
210.6.176.32/2710.6.176.33 – 10.6.176.6210.6.176.63
310.6.176.64/2710.6.176.65 – 10.6.176.9410.6.176.95
410.6.176.96/2710.6.176.97 – 10.6.176.12610.6.176.127
510.6.176.128/2710.6.176.129 – 10.6.176.15810.6.176.159
610.6.176.160/2710.6.176.161 – 10.6.176.19010.6.176.191
710.6.176.192/2710.6.176.193 – 10.6.176.22210.6.176.223
810.6.176.224/2710.6.176.225 – 10.6.176.25410.6.176.255
910.6.177.0/2710.6.177.1 – 10.6.177.3010.6.177.31
1010.6.177.32/2710.6.177.33 – 10.6.177.6210.6.177.63
1110.6.177.64/2710.6.177.65 – 10.6.177.9410.6.177.95
1210.6.177.96/2710.6.177.97 – 10.6.177.12610.6.177.127
1310.6.177.128/2710.6.177.129 – 10.6.177.15810.6.177.159
1410.6.177.160/2710.6.177.161 – 10.6.177.19010.6.177.191
1510.6.177.192/2710.6.177.193 – 10.6.177.22210.6.177.223
1610.6.177.224/2710.6.177.225 – 10.6.177.25410.6.177.255
1710.6.178.0/2710.6.178.1 – 10.6.178.3010.6.178.31
1810.6.178.32/2710.6.178.33 – 10.6.178.6210.6.178.63
1910.6.178.64/2710.6.178.65 – 10.6.178.9410.6.178.95
2010.6.178.96/2710.6.178.97 – 10.6.178.12610.6.178.127
2110.6.178.128/2710.6.178.129 – 10.6.178.15810.6.178.159
2210.6.178.160/2710.6.178.161 – 10.6.178.19010.6.178.191
2310.6.178.192/2710.6.178.193 – 10.6.178.22210.6.178.223
2410.6.178.224/2710.6.178.225 – 10.6.178.25410.6.178.255
2510.6.179.0/2710.6.179.1 – 10.6.179.3010.6.179.31
2610.6.179.32/2710.6.179.33 – 10.6.179.6210.6.179.63
2710.6.179.64/2710.6.179.65 – 10.6.179.9410.6.179.95
2810.6.179.96/2710.6.179.97 – 10.6.179.12610.6.179.127
2910.6.179.128/2710.6.179.129 – 10.6.179.15810.6.179.159
3010.6.179.160/2710.6.179.161 – 10.6.179.19010.6.179.191
3110.6.179.192/2710.6.179.193 – 10.6.179.22210.6.179.223
3210.6.179.224/2710.6.179.225 – 10.6.179.25410.6.179.255
3310.6.180.0/2710.6.180.1 – 10.6.180.3010.6.180.31
3410.6.180.32/2710.6.180.33 – 10.6.180.6210.6.180.63
3510.6.180.64/2710.6.180.65 – 10.6.180.9410.6.180.95
3610.6.180.96/2710.6.180.97 – 10.6.180.12610.6.180.127
3710.6.180.128/2710.6.180.129 – 10.6.180.15810.6.180.159
3810.6.180.160/2710.6.180.161 – 10.6.180.19010.6.180.191
3910.6.180.192/2710.6.180.193 – 10.6.180.22210.6.180.223
4010.6.180.224/2710.6.180.225 – 10.6.180.25410.6.180.255
4110.6.181.0/2710.6.181.1 – 10.6.181.3010.6.181.31
4210.6.181.32/2710.6.181.33 – 10.6.181.6210.6.181.63
4310.6.181.64/2710.6.181.65 – 10.6.181.9410.6.181.95
4410.6.181.96/2710.6.181.97 – 10.6.181.12610.6.181.127
4510.6.181.128/2710.6.181.129 – 10.6.181.15810.6.181.159
4610.6.181.160/2710.6.181.161 – 10.6.181.19010.6.181.191
4710.6.181.192/2710.6.181.193 – 10.6.181.22210.6.181.223
4810.6.181.224/2710.6.181.225 – 10.6.181.25410.6.181.255
4910.6.182.0/2710.6.182.1 – 10.6.182.3010.6.182.31
5010.6.182.32/2710.6.182.33 – 10.6.182.6210.6.182.63
5110.6.182.64/2710.6.182.65 – 10.6.182.9410.6.182.95
5210.6.182.96/2710.6.182.97 – 10.6.182.12610.6.182.127
5310.6.182.128/2710.6.182.129 – 10.6.182.15810.6.182.159
5410.6.182.160/2710.6.182.161 – 10.6.182.19010.6.182.191
5510.6.182.192/2710.6.182.193 – 10.6.182.22210.6.182.223
5610.6.182.224/2710.6.182.225 – 10.6.182.25410.6.182.255
5710.6.183.0/2710.6.183.1 – 10.6.183.3010.6.183.31
5810.6.183.32/2710.6.183.33 – 10.6.183.6210.6.183.63
5910.6.183.64/2710.6.183.65 – 10.6.183.9410.6.183.95
6010.6.183.96/2710.6.183.97 – 10.6.183.12610.6.183.127
6110.6.183.128/2710.6.183.129 – 10.6.183.15810.6.183.159
6210.6.183.160/2710.6.183.161 – 10.6.183.19010.6.183.191
6310.6.183.192/2710.6.183.193 – 10.6.183.22210.6.183.223
6410.6.183.224/2710.6.183.225 – 10.6.183.25410.6.183.255
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 →