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.
private IP (RFC 1918)10.0.18.128/25
network10.0.18.128/25
broadcast10.0.18.255
first host10.0.18.129
last host10.0.18.254
subnet mask255.255.255.128
wildcard0.0.0.127
addresses128
usable hosts126
classA
ipcalc 10.0.18.128/25
address00001010.00000000.00010010.10000000
subnet mask11111111.11111111.11111111.10000000
network00001010.00000000.00010010.10000000
broadcast00001010.00000000.00010010.11111111
green = network part, grey = host part
hex0x0a001280
decimal167776896
reverse dns128.18.0.10.in-addr.arpa
ipv4-mapped::ffff:a00:1280
/25 split into /30 · 32 subnets
close ×| # | network | host range | broadcast |
|---|---|---|---|
| 1 | 10.0.18.128/30 | 10.0.18.129 – 10.0.18.130 | 10.0.18.131 |
| 2 | 10.0.18.132/30 | 10.0.18.133 – 10.0.18.134 | 10.0.18.135 |
| 3 | 10.0.18.136/30 | 10.0.18.137 – 10.0.18.138 | 10.0.18.139 |
| 4 | 10.0.18.140/30 | 10.0.18.141 – 10.0.18.142 | 10.0.18.143 |
| 5 | 10.0.18.144/30 | 10.0.18.145 – 10.0.18.146 | 10.0.18.147 |
| 6 | 10.0.18.148/30 | 10.0.18.149 – 10.0.18.150 | 10.0.18.151 |
| 7 | 10.0.18.152/30 | 10.0.18.153 – 10.0.18.154 | 10.0.18.155 |
| 8 | 10.0.18.156/30 | 10.0.18.157 – 10.0.18.158 | 10.0.18.159 |
| 9 | 10.0.18.160/30 | 10.0.18.161 – 10.0.18.162 | 10.0.18.163 |
| 10 | 10.0.18.164/30 | 10.0.18.165 – 10.0.18.166 | 10.0.18.167 |
| 11 | 10.0.18.168/30 | 10.0.18.169 – 10.0.18.170 | 10.0.18.171 |
| 12 | 10.0.18.172/30 | 10.0.18.173 – 10.0.18.174 | 10.0.18.175 |
| 13 | 10.0.18.176/30 | 10.0.18.177 – 10.0.18.178 | 10.0.18.179 |
| 14 | 10.0.18.180/30 | 10.0.18.181 – 10.0.18.182 | 10.0.18.183 |
| 15 | 10.0.18.184/30 | 10.0.18.185 – 10.0.18.186 | 10.0.18.187 |
| 16 | 10.0.18.188/30 | 10.0.18.189 – 10.0.18.190 | 10.0.18.191 |
| 17 | 10.0.18.192/30 | 10.0.18.193 – 10.0.18.194 | 10.0.18.195 |
| 18 | 10.0.18.196/30 | 10.0.18.197 – 10.0.18.198 | 10.0.18.199 |
| 19 | 10.0.18.200/30 | 10.0.18.201 – 10.0.18.202 | 10.0.18.203 |
| 20 | 10.0.18.204/30 | 10.0.18.205 – 10.0.18.206 | 10.0.18.207 |
| 21 | 10.0.18.208/30 | 10.0.18.209 – 10.0.18.210 | 10.0.18.211 |
| 22 | 10.0.18.212/30 | 10.0.18.213 – 10.0.18.214 | 10.0.18.215 |
| 23 | 10.0.18.216/30 | 10.0.18.217 – 10.0.18.218 | 10.0.18.219 |
| 24 | 10.0.18.220/30 | 10.0.18.221 – 10.0.18.222 | 10.0.18.223 |
| 25 | 10.0.18.224/30 | 10.0.18.225 – 10.0.18.226 | 10.0.18.227 |
| 26 | 10.0.18.228/30 | 10.0.18.229 – 10.0.18.230 | 10.0.18.231 |
| 27 | 10.0.18.232/30 | 10.0.18.233 – 10.0.18.234 | 10.0.18.235 |
| 28 | 10.0.18.236/30 | 10.0.18.237 – 10.0.18.238 | 10.0.18.239 |
| 29 | 10.0.18.240/30 | 10.0.18.241 – 10.0.18.242 | 10.0.18.243 |
| 30 | 10.0.18.244/30 | 10.0.18.245 – 10.0.18.246 | 10.0.18.247 |
| 31 | 10.0.18.248/30 | 10.0.18.249 – 10.0.18.250 | 10.0.18.251 |
| 32 | 10.0.18.252/30 | 10.0.18.253 – 10.0.18.254 | 10.0.18.255 |
01 / table
IPv4 CIDR prefix table.
Click a prefix longer than your network to split it into subnets.
| prefix | subnet mask | addresses | hosts | in your /25 |
|---|---|---|---|---|
| /0 | 0.0.0.0 | 4,294,967,296 | 4,294,967,294 | - |
| /1 | 128.0.0.0 | 2,147,483,648 | 2,147,483,646 | - |
| /2 | 192.0.0.0 | 1,073,741,824 | 1,073,741,822 | - |
| /3 | 224.0.0.0 | 536,870,912 | 536,870,910 | - |
| /4 | 240.0.0.0 | 268,435,456 | 268,435,454 | - |
| /5 | 248.0.0.0 | 134,217,728 | 134,217,726 | - |
| /6 | 252.0.0.0 | 67,108,864 | 67,108,862 | - |
| /7 | 254.0.0.0 | 33,554,432 | 33,554,430 | - |
| /8 | 255.0.0.0 | 16,777,216 | 16,777,214 | - |
| /9 | 255.128.0.0 | 8,388,608 | 8,388,606 | - |
| /10 | 255.192.0.0 | 4,194,304 | 4,194,302 | - |
| /11 | 255.224.0.0 | 2,097,152 | 2,097,150 | - |
| /12 | 255.240.0.0 | 1,048,576 | 1,048,574 | - |
| /13 | 255.248.0.0 | 524,288 | 524,286 | - |
| /14 | 255.252.0.0 | 262,144 | 262,142 | - |
| /15 | 255.254.0.0 | 131,072 | 131,070 | - |
| /16 | 255.255.0.0 | 65,536 | 65,534 | - |
| /17 | 255.255.128.0 | 32,768 | 32,766 | - |
| /18 | 255.255.192.0 | 16,384 | 16,382 | - |
| /19 | 255.255.224.0 | 8,192 | 8,190 | - |
| /20 | 255.255.240.0 | 4,096 | 4,094 | - |
| /21 | 255.255.248.0 | 2,048 | 2,046 | - |
| /22 | 255.255.252.0 | 1,024 | 1,022 | - |
| /23 | 255.255.254.0 | 512 | 510 | - |
| /24 | 255.255.255.0 | 256 | 254 | - |
| /25 | 255.255.255.128 | 128 | 126 | 1 |
| /26 | 255.255.255.192 | 64 | 62 | 2 split → |
| /27 | 255.255.255.224 | 32 | 30 | 4 split → |
| /28 | 255.255.255.240 | 16 | 14 | 8 split → |
| /29 | 255.255.255.248 | 8 | 6 | 16 split → |
| /30 | 255.255.255.252 | 4 | 2 | 32 split → |
| /31 | 255.255.255.254 | 2 | 2 | 64 split → |
| /32 | 255.255.255.255 | 1 | 1 | 128 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.