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)10.167.208.0/21
network10.167.208.0/21
broadcast10.167.215.255
first host10.167.208.1
last host10.167.215.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.167.208.0/21
address00001010.10100111.11010000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.10100111.11010000.00000000
broadcast00001010.10100111.11010111.11111111
green = network part, grey = host part
hex0x0aa7d000
decimal178769920
reverse dns0.208.167.10.in-addr.arpa
ipv4-mapped::ffff:aa7:d000
/21 split into /28 · 128 subnets
close ×| # | network | host range | broadcast |
|---|---|---|---|
| 1 | 10.167.208.0/28 | 10.167.208.1 – 10.167.208.14 | 10.167.208.15 |
| 2 | 10.167.208.16/28 | 10.167.208.17 – 10.167.208.30 | 10.167.208.31 |
| 3 | 10.167.208.32/28 | 10.167.208.33 – 10.167.208.46 | 10.167.208.47 |
| 4 | 10.167.208.48/28 | 10.167.208.49 – 10.167.208.62 | 10.167.208.63 |
| 5 | 10.167.208.64/28 | 10.167.208.65 – 10.167.208.78 | 10.167.208.79 |
| 6 | 10.167.208.80/28 | 10.167.208.81 – 10.167.208.94 | 10.167.208.95 |
| 7 | 10.167.208.96/28 | 10.167.208.97 – 10.167.208.110 | 10.167.208.111 |
| 8 | 10.167.208.112/28 | 10.167.208.113 – 10.167.208.126 | 10.167.208.127 |
| 9 | 10.167.208.128/28 | 10.167.208.129 – 10.167.208.142 | 10.167.208.143 |
| 10 | 10.167.208.144/28 | 10.167.208.145 – 10.167.208.158 | 10.167.208.159 |
| 11 | 10.167.208.160/28 | 10.167.208.161 – 10.167.208.174 | 10.167.208.175 |
| 12 | 10.167.208.176/28 | 10.167.208.177 – 10.167.208.190 | 10.167.208.191 |
| 13 | 10.167.208.192/28 | 10.167.208.193 – 10.167.208.206 | 10.167.208.207 |
| 14 | 10.167.208.208/28 | 10.167.208.209 – 10.167.208.222 | 10.167.208.223 |
| 15 | 10.167.208.224/28 | 10.167.208.225 – 10.167.208.238 | 10.167.208.239 |
| 16 | 10.167.208.240/28 | 10.167.208.241 – 10.167.208.254 | 10.167.208.255 |
| 17 | 10.167.209.0/28 | 10.167.209.1 – 10.167.209.14 | 10.167.209.15 |
| 18 | 10.167.209.16/28 | 10.167.209.17 – 10.167.209.30 | 10.167.209.31 |
| 19 | 10.167.209.32/28 | 10.167.209.33 – 10.167.209.46 | 10.167.209.47 |
| 20 | 10.167.209.48/28 | 10.167.209.49 – 10.167.209.62 | 10.167.209.63 |
| 21 | 10.167.209.64/28 | 10.167.209.65 – 10.167.209.78 | 10.167.209.79 |
| 22 | 10.167.209.80/28 | 10.167.209.81 – 10.167.209.94 | 10.167.209.95 |
| 23 | 10.167.209.96/28 | 10.167.209.97 – 10.167.209.110 | 10.167.209.111 |
| 24 | 10.167.209.112/28 | 10.167.209.113 – 10.167.209.126 | 10.167.209.127 |
| 25 | 10.167.209.128/28 | 10.167.209.129 – 10.167.209.142 | 10.167.209.143 |
| 26 | 10.167.209.144/28 | 10.167.209.145 – 10.167.209.158 | 10.167.209.159 |
| 27 | 10.167.209.160/28 | 10.167.209.161 – 10.167.209.174 | 10.167.209.175 |
| 28 | 10.167.209.176/28 | 10.167.209.177 – 10.167.209.190 | 10.167.209.191 |
| 29 | 10.167.209.192/28 | 10.167.209.193 – 10.167.209.206 | 10.167.209.207 |
| 30 | 10.167.209.208/28 | 10.167.209.209 – 10.167.209.222 | 10.167.209.223 |
| 31 | 10.167.209.224/28 | 10.167.209.225 – 10.167.209.238 | 10.167.209.239 |
| 32 | 10.167.209.240/28 | 10.167.209.241 – 10.167.209.254 | 10.167.209.255 |
| 33 | 10.167.210.0/28 | 10.167.210.1 – 10.167.210.14 | 10.167.210.15 |
| 34 | 10.167.210.16/28 | 10.167.210.17 – 10.167.210.30 | 10.167.210.31 |
| 35 | 10.167.210.32/28 | 10.167.210.33 – 10.167.210.46 | 10.167.210.47 |
| 36 | 10.167.210.48/28 | 10.167.210.49 – 10.167.210.62 | 10.167.210.63 |
| 37 | 10.167.210.64/28 | 10.167.210.65 – 10.167.210.78 | 10.167.210.79 |
| 38 | 10.167.210.80/28 | 10.167.210.81 – 10.167.210.94 | 10.167.210.95 |
| 39 | 10.167.210.96/28 | 10.167.210.97 – 10.167.210.110 | 10.167.210.111 |
| 40 | 10.167.210.112/28 | 10.167.210.113 – 10.167.210.126 | 10.167.210.127 |
| 41 | 10.167.210.128/28 | 10.167.210.129 – 10.167.210.142 | 10.167.210.143 |
| 42 | 10.167.210.144/28 | 10.167.210.145 – 10.167.210.158 | 10.167.210.159 |
| 43 | 10.167.210.160/28 | 10.167.210.161 – 10.167.210.174 | 10.167.210.175 |
| 44 | 10.167.210.176/28 | 10.167.210.177 – 10.167.210.190 | 10.167.210.191 |
| 45 | 10.167.210.192/28 | 10.167.210.193 – 10.167.210.206 | 10.167.210.207 |
| 46 | 10.167.210.208/28 | 10.167.210.209 – 10.167.210.222 | 10.167.210.223 |
| 47 | 10.167.210.224/28 | 10.167.210.225 – 10.167.210.238 | 10.167.210.239 |
| 48 | 10.167.210.240/28 | 10.167.210.241 – 10.167.210.254 | 10.167.210.255 |
| 49 | 10.167.211.0/28 | 10.167.211.1 – 10.167.211.14 | 10.167.211.15 |
| 50 | 10.167.211.16/28 | 10.167.211.17 – 10.167.211.30 | 10.167.211.31 |
| 51 | 10.167.211.32/28 | 10.167.211.33 – 10.167.211.46 | 10.167.211.47 |
| 52 | 10.167.211.48/28 | 10.167.211.49 – 10.167.211.62 | 10.167.211.63 |
| 53 | 10.167.211.64/28 | 10.167.211.65 – 10.167.211.78 | 10.167.211.79 |
| 54 | 10.167.211.80/28 | 10.167.211.81 – 10.167.211.94 | 10.167.211.95 |
| 55 | 10.167.211.96/28 | 10.167.211.97 – 10.167.211.110 | 10.167.211.111 |
| 56 | 10.167.211.112/28 | 10.167.211.113 – 10.167.211.126 | 10.167.211.127 |
| 57 | 10.167.211.128/28 | 10.167.211.129 – 10.167.211.142 | 10.167.211.143 |
| 58 | 10.167.211.144/28 | 10.167.211.145 – 10.167.211.158 | 10.167.211.159 |
| 59 | 10.167.211.160/28 | 10.167.211.161 – 10.167.211.174 | 10.167.211.175 |
| 60 | 10.167.211.176/28 | 10.167.211.177 – 10.167.211.190 | 10.167.211.191 |
| 61 | 10.167.211.192/28 | 10.167.211.193 – 10.167.211.206 | 10.167.211.207 |
| 62 | 10.167.211.208/28 | 10.167.211.209 – 10.167.211.222 | 10.167.211.223 |
| 63 | 10.167.211.224/28 | 10.167.211.225 – 10.167.211.238 | 10.167.211.239 |
| 64 | 10.167.211.240/28 | 10.167.211.241 – 10.167.211.254 | 10.167.211.255 |
| 65 | 10.167.212.0/28 | 10.167.212.1 – 10.167.212.14 | 10.167.212.15 |
| 66 | 10.167.212.16/28 | 10.167.212.17 – 10.167.212.30 | 10.167.212.31 |
| 67 | 10.167.212.32/28 | 10.167.212.33 – 10.167.212.46 | 10.167.212.47 |
| 68 | 10.167.212.48/28 | 10.167.212.49 – 10.167.212.62 | 10.167.212.63 |
| 69 | 10.167.212.64/28 | 10.167.212.65 – 10.167.212.78 | 10.167.212.79 |
| 70 | 10.167.212.80/28 | 10.167.212.81 – 10.167.212.94 | 10.167.212.95 |
| 71 | 10.167.212.96/28 | 10.167.212.97 – 10.167.212.110 | 10.167.212.111 |
| 72 | 10.167.212.112/28 | 10.167.212.113 – 10.167.212.126 | 10.167.212.127 |
| 73 | 10.167.212.128/28 | 10.167.212.129 – 10.167.212.142 | 10.167.212.143 |
| 74 | 10.167.212.144/28 | 10.167.212.145 – 10.167.212.158 | 10.167.212.159 |
| 75 | 10.167.212.160/28 | 10.167.212.161 – 10.167.212.174 | 10.167.212.175 |
| 76 | 10.167.212.176/28 | 10.167.212.177 – 10.167.212.190 | 10.167.212.191 |
| 77 | 10.167.212.192/28 | 10.167.212.193 – 10.167.212.206 | 10.167.212.207 |
| 78 | 10.167.212.208/28 | 10.167.212.209 – 10.167.212.222 | 10.167.212.223 |
| 79 | 10.167.212.224/28 | 10.167.212.225 – 10.167.212.238 | 10.167.212.239 |
| 80 | 10.167.212.240/28 | 10.167.212.241 – 10.167.212.254 | 10.167.212.255 |
| 81 | 10.167.213.0/28 | 10.167.213.1 – 10.167.213.14 | 10.167.213.15 |
| 82 | 10.167.213.16/28 | 10.167.213.17 – 10.167.213.30 | 10.167.213.31 |
| 83 | 10.167.213.32/28 | 10.167.213.33 – 10.167.213.46 | 10.167.213.47 |
| 84 | 10.167.213.48/28 | 10.167.213.49 – 10.167.213.62 | 10.167.213.63 |
| 85 | 10.167.213.64/28 | 10.167.213.65 – 10.167.213.78 | 10.167.213.79 |
| 86 | 10.167.213.80/28 | 10.167.213.81 – 10.167.213.94 | 10.167.213.95 |
| 87 | 10.167.213.96/28 | 10.167.213.97 – 10.167.213.110 | 10.167.213.111 |
| 88 | 10.167.213.112/28 | 10.167.213.113 – 10.167.213.126 | 10.167.213.127 |
| 89 | 10.167.213.128/28 | 10.167.213.129 – 10.167.213.142 | 10.167.213.143 |
| 90 | 10.167.213.144/28 | 10.167.213.145 – 10.167.213.158 | 10.167.213.159 |
| 91 | 10.167.213.160/28 | 10.167.213.161 – 10.167.213.174 | 10.167.213.175 |
| 92 | 10.167.213.176/28 | 10.167.213.177 – 10.167.213.190 | 10.167.213.191 |
| 93 | 10.167.213.192/28 | 10.167.213.193 – 10.167.213.206 | 10.167.213.207 |
| 94 | 10.167.213.208/28 | 10.167.213.209 – 10.167.213.222 | 10.167.213.223 |
| 95 | 10.167.213.224/28 | 10.167.213.225 – 10.167.213.238 | 10.167.213.239 |
| 96 | 10.167.213.240/28 | 10.167.213.241 – 10.167.213.254 | 10.167.213.255 |
| 97 | 10.167.214.0/28 | 10.167.214.1 – 10.167.214.14 | 10.167.214.15 |
| 98 | 10.167.214.16/28 | 10.167.214.17 – 10.167.214.30 | 10.167.214.31 |
| 99 | 10.167.214.32/28 | 10.167.214.33 – 10.167.214.46 | 10.167.214.47 |
| 100 | 10.167.214.48/28 | 10.167.214.49 – 10.167.214.62 | 10.167.214.63 |
| 101 | 10.167.214.64/28 | 10.167.214.65 – 10.167.214.78 | 10.167.214.79 |
| 102 | 10.167.214.80/28 | 10.167.214.81 – 10.167.214.94 | 10.167.214.95 |
| 103 | 10.167.214.96/28 | 10.167.214.97 – 10.167.214.110 | 10.167.214.111 |
| 104 | 10.167.214.112/28 | 10.167.214.113 – 10.167.214.126 | 10.167.214.127 |
| 105 | 10.167.214.128/28 | 10.167.214.129 – 10.167.214.142 | 10.167.214.143 |
| 106 | 10.167.214.144/28 | 10.167.214.145 – 10.167.214.158 | 10.167.214.159 |
| 107 | 10.167.214.160/28 | 10.167.214.161 – 10.167.214.174 | 10.167.214.175 |
| 108 | 10.167.214.176/28 | 10.167.214.177 – 10.167.214.190 | 10.167.214.191 |
| 109 | 10.167.214.192/28 | 10.167.214.193 – 10.167.214.206 | 10.167.214.207 |
| 110 | 10.167.214.208/28 | 10.167.214.209 – 10.167.214.222 | 10.167.214.223 |
| 111 | 10.167.214.224/28 | 10.167.214.225 – 10.167.214.238 | 10.167.214.239 |
| 112 | 10.167.214.240/28 | 10.167.214.241 – 10.167.214.254 | 10.167.214.255 |
| 113 | 10.167.215.0/28 | 10.167.215.1 – 10.167.215.14 | 10.167.215.15 |
| 114 | 10.167.215.16/28 | 10.167.215.17 – 10.167.215.30 | 10.167.215.31 |
| 115 | 10.167.215.32/28 | 10.167.215.33 – 10.167.215.46 | 10.167.215.47 |
| 116 | 10.167.215.48/28 | 10.167.215.49 – 10.167.215.62 | 10.167.215.63 |
| 117 | 10.167.215.64/28 | 10.167.215.65 – 10.167.215.78 | 10.167.215.79 |
| 118 | 10.167.215.80/28 | 10.167.215.81 – 10.167.215.94 | 10.167.215.95 |
| 119 | 10.167.215.96/28 | 10.167.215.97 – 10.167.215.110 | 10.167.215.111 |
| 120 | 10.167.215.112/28 | 10.167.215.113 – 10.167.215.126 | 10.167.215.127 |
| 121 | 10.167.215.128/28 | 10.167.215.129 – 10.167.215.142 | 10.167.215.143 |
| 122 | 10.167.215.144/28 | 10.167.215.145 – 10.167.215.158 | 10.167.215.159 |
| 123 | 10.167.215.160/28 | 10.167.215.161 – 10.167.215.174 | 10.167.215.175 |
| 124 | 10.167.215.176/28 | 10.167.215.177 – 10.167.215.190 | 10.167.215.191 |
| 125 | 10.167.215.192/28 | 10.167.215.193 – 10.167.215.206 | 10.167.215.207 |
| 126 | 10.167.215.208/28 | 10.167.215.209 – 10.167.215.222 | 10.167.215.223 |
| 127 | 10.167.215.224/28 | 10.167.215.225 – 10.167.215.238 | 10.167.215.239 |
| 128 | 10.167.215.240/28 | 10.167.215.241 – 10.167.215.254 | 10.167.215.255 |
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 /21 |
|---|---|---|---|---|
| /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 | 1 |
| /22 | 255.255.252.0 | 1,024 | 1,022 | 2 split → |
| /23 | 255.255.254.0 | 512 | 510 | 4 split → |
| /24 | 255.255.255.0 | 256 | 254 | 8 split → |
| /25 | 255.255.255.128 | 128 | 126 | 16 split → |
| /26 | 255.255.255.192 | 64 | 62 | 32 split → |
| /27 | 255.255.255.224 | 32 | 30 | 64 split → |
| /28 | 255.255.255.240 | 16 | 14 | 128 split → |
| /29 | 255.255.255.248 | 8 | 6 | 256 split → |
| /30 | 255.255.255.252 | 4 | 2 | 512 split → |
| /31 | 255.255.255.254 | 2 | 2 | 1,024 split → |
| /32 | 255.255.255.255 | 1 | 1 | 2,048 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.