ip
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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)10.0.81.128/25
network10.0.81.128/25
broadcast10.0.81.255
first host10.0.81.129
last host10.0.81.254
subnet mask255.255.255.128
wildcard0.0.0.127
addresses128
usable hosts126
classA
ipcalc 10.0.81.128/25
address00001010.00000000.01010001.10000000
subnet mask11111111.11111111.11111111.10000000
network00001010.00000000.01010001.10000000
broadcast00001010.00000000.01010001.11111111
green = network part, grey = host part
hex0x0a005180
decimal167793024
reverse dns128.81.0.10.in-addr.arpa
ipv4-mapped::ffff:a00:5180

/25 split into /30 · 32 subnets

close ×
#networkhost rangebroadcast
110.0.81.128/3010.0.81.129 – 10.0.81.13010.0.81.131
210.0.81.132/3010.0.81.133 – 10.0.81.13410.0.81.135
310.0.81.136/3010.0.81.137 – 10.0.81.13810.0.81.139
410.0.81.140/3010.0.81.141 – 10.0.81.14210.0.81.143
510.0.81.144/3010.0.81.145 – 10.0.81.14610.0.81.147
610.0.81.148/3010.0.81.149 – 10.0.81.15010.0.81.151
710.0.81.152/3010.0.81.153 – 10.0.81.15410.0.81.155
810.0.81.156/3010.0.81.157 – 10.0.81.15810.0.81.159
910.0.81.160/3010.0.81.161 – 10.0.81.16210.0.81.163
1010.0.81.164/3010.0.81.165 – 10.0.81.16610.0.81.167
1110.0.81.168/3010.0.81.169 – 10.0.81.17010.0.81.171
1210.0.81.172/3010.0.81.173 – 10.0.81.17410.0.81.175
1310.0.81.176/3010.0.81.177 – 10.0.81.17810.0.81.179
1410.0.81.180/3010.0.81.181 – 10.0.81.18210.0.81.183
1510.0.81.184/3010.0.81.185 – 10.0.81.18610.0.81.187
1610.0.81.188/3010.0.81.189 – 10.0.81.19010.0.81.191
1710.0.81.192/3010.0.81.193 – 10.0.81.19410.0.81.195
1810.0.81.196/3010.0.81.197 – 10.0.81.19810.0.81.199
1910.0.81.200/3010.0.81.201 – 10.0.81.20210.0.81.203
2010.0.81.204/3010.0.81.205 – 10.0.81.20610.0.81.207
2110.0.81.208/3010.0.81.209 – 10.0.81.21010.0.81.211
2210.0.81.212/3010.0.81.213 – 10.0.81.21410.0.81.215
2310.0.81.216/3010.0.81.217 – 10.0.81.21810.0.81.219
2410.0.81.220/3010.0.81.221 – 10.0.81.22210.0.81.223
2510.0.81.224/3010.0.81.225 – 10.0.81.22610.0.81.227
2610.0.81.228/3010.0.81.229 – 10.0.81.23010.0.81.231
2710.0.81.232/3010.0.81.233 – 10.0.81.23410.0.81.235
2810.0.81.236/3010.0.81.237 – 10.0.81.23810.0.81.239
2910.0.81.240/3010.0.81.241 – 10.0.81.24210.0.81.243
3010.0.81.244/3010.0.81.245 – 10.0.81.24610.0.81.247
3110.0.81.248/3010.0.81.249 – 10.0.81.25010.0.81.251
3210.0.81.252/3010.0.81.253 – 10.0.81.25410.0.81.255
01 / table

IPv4 CIDR prefix table.

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

prefixsubnet maskaddresseshostsin your /25
/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-
/25255.255.255.1281281261
/26255.255.255.19264622 split →
/27255.255.255.22432304 split →
/28255.255.255.24016148 split →
/29255.255.255.2488616 split →
/30255.255.255.2524232 split →
/31255.255.255.2542264 split →
/32255.255.255.25511128 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 →