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)10.0.121.128/25
network10.0.121.128/25
broadcast10.0.121.255
first host10.0.121.129
last host10.0.121.254
subnet mask255.255.255.128
wildcard0.0.0.127
addresses128
usable hosts126
classA
ipcalc 10.0.121.128/25
address00001010.00000000.01111001.10000000
subnet mask11111111.11111111.11111111.10000000
network00001010.00000000.01111001.10000000
broadcast00001010.00000000.01111001.11111111
green = network part, grey = host part
hex0x0a007980
decimal167803264
reverse dns128.121.0.10.in-addr.arpa
ipv4-mapped::ffff:a00:7980
/25 split into /31 · 64 subnets
close ×| # | network | host range | broadcast |
|---|---|---|---|
| 1 | 10.0.121.128/31 | 10.0.121.128 – 10.0.121.129 | 10.0.121.129 |
| 2 | 10.0.121.130/31 | 10.0.121.130 – 10.0.121.131 | 10.0.121.131 |
| 3 | 10.0.121.132/31 | 10.0.121.132 – 10.0.121.133 | 10.0.121.133 |
| 4 | 10.0.121.134/31 | 10.0.121.134 – 10.0.121.135 | 10.0.121.135 |
| 5 | 10.0.121.136/31 | 10.0.121.136 – 10.0.121.137 | 10.0.121.137 |
| 6 | 10.0.121.138/31 | 10.0.121.138 – 10.0.121.139 | 10.0.121.139 |
| 7 | 10.0.121.140/31 | 10.0.121.140 – 10.0.121.141 | 10.0.121.141 |
| 8 | 10.0.121.142/31 | 10.0.121.142 – 10.0.121.143 | 10.0.121.143 |
| 9 | 10.0.121.144/31 | 10.0.121.144 – 10.0.121.145 | 10.0.121.145 |
| 10 | 10.0.121.146/31 | 10.0.121.146 – 10.0.121.147 | 10.0.121.147 |
| 11 | 10.0.121.148/31 | 10.0.121.148 – 10.0.121.149 | 10.0.121.149 |
| 12 | 10.0.121.150/31 | 10.0.121.150 – 10.0.121.151 | 10.0.121.151 |
| 13 | 10.0.121.152/31 | 10.0.121.152 – 10.0.121.153 | 10.0.121.153 |
| 14 | 10.0.121.154/31 | 10.0.121.154 – 10.0.121.155 | 10.0.121.155 |
| 15 | 10.0.121.156/31 | 10.0.121.156 – 10.0.121.157 | 10.0.121.157 |
| 16 | 10.0.121.158/31 | 10.0.121.158 – 10.0.121.159 | 10.0.121.159 |
| 17 | 10.0.121.160/31 | 10.0.121.160 – 10.0.121.161 | 10.0.121.161 |
| 18 | 10.0.121.162/31 | 10.0.121.162 – 10.0.121.163 | 10.0.121.163 |
| 19 | 10.0.121.164/31 | 10.0.121.164 – 10.0.121.165 | 10.0.121.165 |
| 20 | 10.0.121.166/31 | 10.0.121.166 – 10.0.121.167 | 10.0.121.167 |
| 21 | 10.0.121.168/31 | 10.0.121.168 – 10.0.121.169 | 10.0.121.169 |
| 22 | 10.0.121.170/31 | 10.0.121.170 – 10.0.121.171 | 10.0.121.171 |
| 23 | 10.0.121.172/31 | 10.0.121.172 – 10.0.121.173 | 10.0.121.173 |
| 24 | 10.0.121.174/31 | 10.0.121.174 – 10.0.121.175 | 10.0.121.175 |
| 25 | 10.0.121.176/31 | 10.0.121.176 – 10.0.121.177 | 10.0.121.177 |
| 26 | 10.0.121.178/31 | 10.0.121.178 – 10.0.121.179 | 10.0.121.179 |
| 27 | 10.0.121.180/31 | 10.0.121.180 – 10.0.121.181 | 10.0.121.181 |
| 28 | 10.0.121.182/31 | 10.0.121.182 – 10.0.121.183 | 10.0.121.183 |
| 29 | 10.0.121.184/31 | 10.0.121.184 – 10.0.121.185 | 10.0.121.185 |
| 30 | 10.0.121.186/31 | 10.0.121.186 – 10.0.121.187 | 10.0.121.187 |
| 31 | 10.0.121.188/31 | 10.0.121.188 – 10.0.121.189 | 10.0.121.189 |
| 32 | 10.0.121.190/31 | 10.0.121.190 – 10.0.121.191 | 10.0.121.191 |
| 33 | 10.0.121.192/31 | 10.0.121.192 – 10.0.121.193 | 10.0.121.193 |
| 34 | 10.0.121.194/31 | 10.0.121.194 – 10.0.121.195 | 10.0.121.195 |
| 35 | 10.0.121.196/31 | 10.0.121.196 – 10.0.121.197 | 10.0.121.197 |
| 36 | 10.0.121.198/31 | 10.0.121.198 – 10.0.121.199 | 10.0.121.199 |
| 37 | 10.0.121.200/31 | 10.0.121.200 – 10.0.121.201 | 10.0.121.201 |
| 38 | 10.0.121.202/31 | 10.0.121.202 – 10.0.121.203 | 10.0.121.203 |
| 39 | 10.0.121.204/31 | 10.0.121.204 – 10.0.121.205 | 10.0.121.205 |
| 40 | 10.0.121.206/31 | 10.0.121.206 – 10.0.121.207 | 10.0.121.207 |
| 41 | 10.0.121.208/31 | 10.0.121.208 – 10.0.121.209 | 10.0.121.209 |
| 42 | 10.0.121.210/31 | 10.0.121.210 – 10.0.121.211 | 10.0.121.211 |
| 43 | 10.0.121.212/31 | 10.0.121.212 – 10.0.121.213 | 10.0.121.213 |
| 44 | 10.0.121.214/31 | 10.0.121.214 – 10.0.121.215 | 10.0.121.215 |
| 45 | 10.0.121.216/31 | 10.0.121.216 – 10.0.121.217 | 10.0.121.217 |
| 46 | 10.0.121.218/31 | 10.0.121.218 – 10.0.121.219 | 10.0.121.219 |
| 47 | 10.0.121.220/31 | 10.0.121.220 – 10.0.121.221 | 10.0.121.221 |
| 48 | 10.0.121.222/31 | 10.0.121.222 – 10.0.121.223 | 10.0.121.223 |
| 49 | 10.0.121.224/31 | 10.0.121.224 – 10.0.121.225 | 10.0.121.225 |
| 50 | 10.0.121.226/31 | 10.0.121.226 – 10.0.121.227 | 10.0.121.227 |
| 51 | 10.0.121.228/31 | 10.0.121.228 – 10.0.121.229 | 10.0.121.229 |
| 52 | 10.0.121.230/31 | 10.0.121.230 – 10.0.121.231 | 10.0.121.231 |
| 53 | 10.0.121.232/31 | 10.0.121.232 – 10.0.121.233 | 10.0.121.233 |
| 54 | 10.0.121.234/31 | 10.0.121.234 – 10.0.121.235 | 10.0.121.235 |
| 55 | 10.0.121.236/31 | 10.0.121.236 – 10.0.121.237 | 10.0.121.237 |
| 56 | 10.0.121.238/31 | 10.0.121.238 – 10.0.121.239 | 10.0.121.239 |
| 57 | 10.0.121.240/31 | 10.0.121.240 – 10.0.121.241 | 10.0.121.241 |
| 58 | 10.0.121.242/31 | 10.0.121.242 – 10.0.121.243 | 10.0.121.243 |
| 59 | 10.0.121.244/31 | 10.0.121.244 – 10.0.121.245 | 10.0.121.245 |
| 60 | 10.0.121.246/31 | 10.0.121.246 – 10.0.121.247 | 10.0.121.247 |
| 61 | 10.0.121.248/31 | 10.0.121.248 – 10.0.121.249 | 10.0.121.249 |
| 62 | 10.0.121.250/31 | 10.0.121.250 – 10.0.121.251 | 10.0.121.251 |
| 63 | 10.0.121.252/31 | 10.0.121.252 – 10.0.121.253 | 10.0.121.253 |
| 64 | 10.0.121.254/31 | 10.0.121.254 – 10.0.121.255 | 10.0.121.255 |
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.