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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)10.2.200.0/21
network10.2.200.0/21
broadcast10.2.207.255
first host10.2.200.1
last host10.2.207.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.2.200.0/21
address00001010.00000010.11001000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000010.11001000.00000000
broadcast00001010.00000010.11001111.11111111
green = network part, grey = host part
hex0x0a02c800
decimal167954432
reverse dns0.200.2.10.in-addr.arpa
ipv4-mapped::ffff:a02:c800

/21 split into /26 · 32 subnets

close ×
#networkhost rangebroadcast
110.2.200.0/2610.2.200.1 – 10.2.200.6210.2.200.63
210.2.200.64/2610.2.200.65 – 10.2.200.12610.2.200.127
310.2.200.128/2610.2.200.129 – 10.2.200.19010.2.200.191
410.2.200.192/2610.2.200.193 – 10.2.200.25410.2.200.255
510.2.201.0/2610.2.201.1 – 10.2.201.6210.2.201.63
610.2.201.64/2610.2.201.65 – 10.2.201.12610.2.201.127
710.2.201.128/2610.2.201.129 – 10.2.201.19010.2.201.191
810.2.201.192/2610.2.201.193 – 10.2.201.25410.2.201.255
910.2.202.0/2610.2.202.1 – 10.2.202.6210.2.202.63
1010.2.202.64/2610.2.202.65 – 10.2.202.12610.2.202.127
1110.2.202.128/2610.2.202.129 – 10.2.202.19010.2.202.191
1210.2.202.192/2610.2.202.193 – 10.2.202.25410.2.202.255
1310.2.203.0/2610.2.203.1 – 10.2.203.6210.2.203.63
1410.2.203.64/2610.2.203.65 – 10.2.203.12610.2.203.127
1510.2.203.128/2610.2.203.129 – 10.2.203.19010.2.203.191
1610.2.203.192/2610.2.203.193 – 10.2.203.25410.2.203.255
1710.2.204.0/2610.2.204.1 – 10.2.204.6210.2.204.63
1810.2.204.64/2610.2.204.65 – 10.2.204.12610.2.204.127
1910.2.204.128/2610.2.204.129 – 10.2.204.19010.2.204.191
2010.2.204.192/2610.2.204.193 – 10.2.204.25410.2.204.255
2110.2.205.0/2610.2.205.1 – 10.2.205.6210.2.205.63
2210.2.205.64/2610.2.205.65 – 10.2.205.12610.2.205.127
2310.2.205.128/2610.2.205.129 – 10.2.205.19010.2.205.191
2410.2.205.192/2610.2.205.193 – 10.2.205.25410.2.205.255
2510.2.206.0/2610.2.206.1 – 10.2.206.6210.2.206.63
2610.2.206.64/2610.2.206.65 – 10.2.206.12610.2.206.127
2710.2.206.128/2610.2.206.129 – 10.2.206.19010.2.206.191
2810.2.206.192/2610.2.206.193 – 10.2.206.25410.2.206.255
2910.2.207.0/2610.2.207.1 – 10.2.207.6210.2.207.63
3010.2.207.64/2610.2.207.65 – 10.2.207.12610.2.207.127
3110.2.207.128/2610.2.207.129 – 10.2.207.19010.2.207.191
3210.2.207.192/2610.2.207.193 – 10.2.207.25410.2.207.255
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 →