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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)10.6.0.0/21
network10.6.0.0/21
broadcast10.6.7.255
first host10.6.0.1
last host10.6.7.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.6.0.0/21
address00001010.00000110.00000000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000110.00000000.00000000
broadcast00001010.00000110.00000111.11111111
green = network part, grey = host part
hex0x0a060000
decimal168165376
reverse dns0.0.6.10.in-addr.arpa
ipv4-mapped::ffff:a06:0

/21 split into /27 · 64 subnets

close ×
#networkhost rangebroadcast
110.6.0.0/2710.6.0.1 – 10.6.0.3010.6.0.31
210.6.0.32/2710.6.0.33 – 10.6.0.6210.6.0.63
310.6.0.64/2710.6.0.65 – 10.6.0.9410.6.0.95
410.6.0.96/2710.6.0.97 – 10.6.0.12610.6.0.127
510.6.0.128/2710.6.0.129 – 10.6.0.15810.6.0.159
610.6.0.160/2710.6.0.161 – 10.6.0.19010.6.0.191
710.6.0.192/2710.6.0.193 – 10.6.0.22210.6.0.223
810.6.0.224/2710.6.0.225 – 10.6.0.25410.6.0.255
910.6.1.0/2710.6.1.1 – 10.6.1.3010.6.1.31
1010.6.1.32/2710.6.1.33 – 10.6.1.6210.6.1.63
1110.6.1.64/2710.6.1.65 – 10.6.1.9410.6.1.95
1210.6.1.96/2710.6.1.97 – 10.6.1.12610.6.1.127
1310.6.1.128/2710.6.1.129 – 10.6.1.15810.6.1.159
1410.6.1.160/2710.6.1.161 – 10.6.1.19010.6.1.191
1510.6.1.192/2710.6.1.193 – 10.6.1.22210.6.1.223
1610.6.1.224/2710.6.1.225 – 10.6.1.25410.6.1.255
1710.6.2.0/2710.6.2.1 – 10.6.2.3010.6.2.31
1810.6.2.32/2710.6.2.33 – 10.6.2.6210.6.2.63
1910.6.2.64/2710.6.2.65 – 10.6.2.9410.6.2.95
2010.6.2.96/2710.6.2.97 – 10.6.2.12610.6.2.127
2110.6.2.128/2710.6.2.129 – 10.6.2.15810.6.2.159
2210.6.2.160/2710.6.2.161 – 10.6.2.19010.6.2.191
2310.6.2.192/2710.6.2.193 – 10.6.2.22210.6.2.223
2410.6.2.224/2710.6.2.225 – 10.6.2.25410.6.2.255
2510.6.3.0/2710.6.3.1 – 10.6.3.3010.6.3.31
2610.6.3.32/2710.6.3.33 – 10.6.3.6210.6.3.63
2710.6.3.64/2710.6.3.65 – 10.6.3.9410.6.3.95
2810.6.3.96/2710.6.3.97 – 10.6.3.12610.6.3.127
2910.6.3.128/2710.6.3.129 – 10.6.3.15810.6.3.159
3010.6.3.160/2710.6.3.161 – 10.6.3.19010.6.3.191
3110.6.3.192/2710.6.3.193 – 10.6.3.22210.6.3.223
3210.6.3.224/2710.6.3.225 – 10.6.3.25410.6.3.255
3310.6.4.0/2710.6.4.1 – 10.6.4.3010.6.4.31
3410.6.4.32/2710.6.4.33 – 10.6.4.6210.6.4.63
3510.6.4.64/2710.6.4.65 – 10.6.4.9410.6.4.95
3610.6.4.96/2710.6.4.97 – 10.6.4.12610.6.4.127
3710.6.4.128/2710.6.4.129 – 10.6.4.15810.6.4.159
3810.6.4.160/2710.6.4.161 – 10.6.4.19010.6.4.191
3910.6.4.192/2710.6.4.193 – 10.6.4.22210.6.4.223
4010.6.4.224/2710.6.4.225 – 10.6.4.25410.6.4.255
4110.6.5.0/2710.6.5.1 – 10.6.5.3010.6.5.31
4210.6.5.32/2710.6.5.33 – 10.6.5.6210.6.5.63
4310.6.5.64/2710.6.5.65 – 10.6.5.9410.6.5.95
4410.6.5.96/2710.6.5.97 – 10.6.5.12610.6.5.127
4510.6.5.128/2710.6.5.129 – 10.6.5.15810.6.5.159
4610.6.5.160/2710.6.5.161 – 10.6.5.19010.6.5.191
4710.6.5.192/2710.6.5.193 – 10.6.5.22210.6.5.223
4810.6.5.224/2710.6.5.225 – 10.6.5.25410.6.5.255
4910.6.6.0/2710.6.6.1 – 10.6.6.3010.6.6.31
5010.6.6.32/2710.6.6.33 – 10.6.6.6210.6.6.63
5110.6.6.64/2710.6.6.65 – 10.6.6.9410.6.6.95
5210.6.6.96/2710.6.6.97 – 10.6.6.12610.6.6.127
5310.6.6.128/2710.6.6.129 – 10.6.6.15810.6.6.159
5410.6.6.160/2710.6.6.161 – 10.6.6.19010.6.6.191
5510.6.6.192/2710.6.6.193 – 10.6.6.22210.6.6.223
5610.6.6.224/2710.6.6.225 – 10.6.6.25410.6.6.255
5710.6.7.0/2710.6.7.1 – 10.6.7.3010.6.7.31
5810.6.7.32/2710.6.7.33 – 10.6.7.6210.6.7.63
5910.6.7.64/2710.6.7.65 – 10.6.7.9410.6.7.95
6010.6.7.96/2710.6.7.97 – 10.6.7.12610.6.7.127
6110.6.7.128/2710.6.7.129 – 10.6.7.15810.6.7.159
6210.6.7.160/2710.6.7.161 – 10.6.7.19010.6.7.191
6310.6.7.192/2710.6.7.193 – 10.6.7.22210.6.7.223
6410.6.7.224/2710.6.7.225 – 10.6.7.25410.6.7.255
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 →