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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)172.16.4.128/27
network172.16.4.128/27
broadcast172.16.4.159
first host172.16.4.129
last host172.16.4.158
subnet mask255.255.255.224
wildcard0.0.0.31
addresses32
usable hosts30
classB
ipcalc 172.16.4.128/27
address10101100.00010000.00000100.10000000
subnet mask11111111.11111111.11111111.11100000
network10101100.00010000.00000100.10000000
broadcast10101100.00010000.00000100.10011111
green = network part, grey = host part
hex0xac100480
decimal2886730880
reverse dns128.4.16.172.in-addr.arpa
ipv4-mapped::ffff:ac10:480

/27 split into /31 · 16 subnets

close ×
#networkhost rangebroadcast
1172.16.4.128/31172.16.4.128 – 172.16.4.129172.16.4.129
2172.16.4.130/31172.16.4.130 – 172.16.4.131172.16.4.131
3172.16.4.132/31172.16.4.132 – 172.16.4.133172.16.4.133
4172.16.4.134/31172.16.4.134 – 172.16.4.135172.16.4.135
5172.16.4.136/31172.16.4.136 – 172.16.4.137172.16.4.137
6172.16.4.138/31172.16.4.138 – 172.16.4.139172.16.4.139
7172.16.4.140/31172.16.4.140 – 172.16.4.141172.16.4.141
8172.16.4.142/31172.16.4.142 – 172.16.4.143172.16.4.143
9172.16.4.144/31172.16.4.144 – 172.16.4.145172.16.4.145
10172.16.4.146/31172.16.4.146 – 172.16.4.147172.16.4.147
11172.16.4.148/31172.16.4.148 – 172.16.4.149172.16.4.149
12172.16.4.150/31172.16.4.150 – 172.16.4.151172.16.4.151
13172.16.4.152/31172.16.4.152 – 172.16.4.153172.16.4.153
14172.16.4.154/31172.16.4.154 – 172.16.4.155172.16.4.155
15172.16.4.156/31172.16.4.156 – 172.16.4.157172.16.4.157
16172.16.4.158/31172.16.4.158 – 172.16.4.159172.16.4.159
01 / table

IPv4 CIDR prefix table.

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

prefixsubnet maskaddresseshostsin your /27
/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-
/21255.255.248.02,0482,046-
/22255.255.252.01,0241,022-
/23255.255.254.0512510-
/24255.255.255.0256254-
/25255.255.255.128128126-
/26255.255.255.1926462-
/27255.255.255.22432301
/28255.255.255.24016142 split →
/29255.255.255.248864 split →
/30255.255.255.252428 split →
/31255.255.255.2542216 split →
/32255.255.255.2551132 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 →