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)10.167.64.0/21
network10.167.64.0/21
broadcast10.167.71.255
first host10.167.64.1
last host10.167.71.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.167.64.0/21
address00001010.10100111.01000000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.10100111.01000000.00000000
broadcast00001010.10100111.01000111.11111111
green = network part, grey = host part
hex0x0aa74000
decimal178733056
reverse dns0.64.167.10.in-addr.arpa
ipv4-mapped::ffff:aa7:4000
/21 split into /28 · 128 subnets
close ×| # | network | host range | broadcast |
|---|---|---|---|
| 1 | 10.167.64.0/28 | 10.167.64.1 – 10.167.64.14 | 10.167.64.15 |
| 2 | 10.167.64.16/28 | 10.167.64.17 – 10.167.64.30 | 10.167.64.31 |
| 3 | 10.167.64.32/28 | 10.167.64.33 – 10.167.64.46 | 10.167.64.47 |
| 4 | 10.167.64.48/28 | 10.167.64.49 – 10.167.64.62 | 10.167.64.63 |
| 5 | 10.167.64.64/28 | 10.167.64.65 – 10.167.64.78 | 10.167.64.79 |
| 6 | 10.167.64.80/28 | 10.167.64.81 – 10.167.64.94 | 10.167.64.95 |
| 7 | 10.167.64.96/28 | 10.167.64.97 – 10.167.64.110 | 10.167.64.111 |
| 8 | 10.167.64.112/28 | 10.167.64.113 – 10.167.64.126 | 10.167.64.127 |
| 9 | 10.167.64.128/28 | 10.167.64.129 – 10.167.64.142 | 10.167.64.143 |
| 10 | 10.167.64.144/28 | 10.167.64.145 – 10.167.64.158 | 10.167.64.159 |
| 11 | 10.167.64.160/28 | 10.167.64.161 – 10.167.64.174 | 10.167.64.175 |
| 12 | 10.167.64.176/28 | 10.167.64.177 – 10.167.64.190 | 10.167.64.191 |
| 13 | 10.167.64.192/28 | 10.167.64.193 – 10.167.64.206 | 10.167.64.207 |
| 14 | 10.167.64.208/28 | 10.167.64.209 – 10.167.64.222 | 10.167.64.223 |
| 15 | 10.167.64.224/28 | 10.167.64.225 – 10.167.64.238 | 10.167.64.239 |
| 16 | 10.167.64.240/28 | 10.167.64.241 – 10.167.64.254 | 10.167.64.255 |
| 17 | 10.167.65.0/28 | 10.167.65.1 – 10.167.65.14 | 10.167.65.15 |
| 18 | 10.167.65.16/28 | 10.167.65.17 – 10.167.65.30 | 10.167.65.31 |
| 19 | 10.167.65.32/28 | 10.167.65.33 – 10.167.65.46 | 10.167.65.47 |
| 20 | 10.167.65.48/28 | 10.167.65.49 – 10.167.65.62 | 10.167.65.63 |
| 21 | 10.167.65.64/28 | 10.167.65.65 – 10.167.65.78 | 10.167.65.79 |
| 22 | 10.167.65.80/28 | 10.167.65.81 – 10.167.65.94 | 10.167.65.95 |
| 23 | 10.167.65.96/28 | 10.167.65.97 – 10.167.65.110 | 10.167.65.111 |
| 24 | 10.167.65.112/28 | 10.167.65.113 – 10.167.65.126 | 10.167.65.127 |
| 25 | 10.167.65.128/28 | 10.167.65.129 – 10.167.65.142 | 10.167.65.143 |
| 26 | 10.167.65.144/28 | 10.167.65.145 – 10.167.65.158 | 10.167.65.159 |
| 27 | 10.167.65.160/28 | 10.167.65.161 – 10.167.65.174 | 10.167.65.175 |
| 28 | 10.167.65.176/28 | 10.167.65.177 – 10.167.65.190 | 10.167.65.191 |
| 29 | 10.167.65.192/28 | 10.167.65.193 – 10.167.65.206 | 10.167.65.207 |
| 30 | 10.167.65.208/28 | 10.167.65.209 – 10.167.65.222 | 10.167.65.223 |
| 31 | 10.167.65.224/28 | 10.167.65.225 – 10.167.65.238 | 10.167.65.239 |
| 32 | 10.167.65.240/28 | 10.167.65.241 – 10.167.65.254 | 10.167.65.255 |
| 33 | 10.167.66.0/28 | 10.167.66.1 – 10.167.66.14 | 10.167.66.15 |
| 34 | 10.167.66.16/28 | 10.167.66.17 – 10.167.66.30 | 10.167.66.31 |
| 35 | 10.167.66.32/28 | 10.167.66.33 – 10.167.66.46 | 10.167.66.47 |
| 36 | 10.167.66.48/28 | 10.167.66.49 – 10.167.66.62 | 10.167.66.63 |
| 37 | 10.167.66.64/28 | 10.167.66.65 – 10.167.66.78 | 10.167.66.79 |
| 38 | 10.167.66.80/28 | 10.167.66.81 – 10.167.66.94 | 10.167.66.95 |
| 39 | 10.167.66.96/28 | 10.167.66.97 – 10.167.66.110 | 10.167.66.111 |
| 40 | 10.167.66.112/28 | 10.167.66.113 – 10.167.66.126 | 10.167.66.127 |
| 41 | 10.167.66.128/28 | 10.167.66.129 – 10.167.66.142 | 10.167.66.143 |
| 42 | 10.167.66.144/28 | 10.167.66.145 – 10.167.66.158 | 10.167.66.159 |
| 43 | 10.167.66.160/28 | 10.167.66.161 – 10.167.66.174 | 10.167.66.175 |
| 44 | 10.167.66.176/28 | 10.167.66.177 – 10.167.66.190 | 10.167.66.191 |
| 45 | 10.167.66.192/28 | 10.167.66.193 – 10.167.66.206 | 10.167.66.207 |
| 46 | 10.167.66.208/28 | 10.167.66.209 – 10.167.66.222 | 10.167.66.223 |
| 47 | 10.167.66.224/28 | 10.167.66.225 – 10.167.66.238 | 10.167.66.239 |
| 48 | 10.167.66.240/28 | 10.167.66.241 – 10.167.66.254 | 10.167.66.255 |
| 49 | 10.167.67.0/28 | 10.167.67.1 – 10.167.67.14 | 10.167.67.15 |
| 50 | 10.167.67.16/28 | 10.167.67.17 – 10.167.67.30 | 10.167.67.31 |
| 51 | 10.167.67.32/28 | 10.167.67.33 – 10.167.67.46 | 10.167.67.47 |
| 52 | 10.167.67.48/28 | 10.167.67.49 – 10.167.67.62 | 10.167.67.63 |
| 53 | 10.167.67.64/28 | 10.167.67.65 – 10.167.67.78 | 10.167.67.79 |
| 54 | 10.167.67.80/28 | 10.167.67.81 – 10.167.67.94 | 10.167.67.95 |
| 55 | 10.167.67.96/28 | 10.167.67.97 – 10.167.67.110 | 10.167.67.111 |
| 56 | 10.167.67.112/28 | 10.167.67.113 – 10.167.67.126 | 10.167.67.127 |
| 57 | 10.167.67.128/28 | 10.167.67.129 – 10.167.67.142 | 10.167.67.143 |
| 58 | 10.167.67.144/28 | 10.167.67.145 – 10.167.67.158 | 10.167.67.159 |
| 59 | 10.167.67.160/28 | 10.167.67.161 – 10.167.67.174 | 10.167.67.175 |
| 60 | 10.167.67.176/28 | 10.167.67.177 – 10.167.67.190 | 10.167.67.191 |
| 61 | 10.167.67.192/28 | 10.167.67.193 – 10.167.67.206 | 10.167.67.207 |
| 62 | 10.167.67.208/28 | 10.167.67.209 – 10.167.67.222 | 10.167.67.223 |
| 63 | 10.167.67.224/28 | 10.167.67.225 – 10.167.67.238 | 10.167.67.239 |
| 64 | 10.167.67.240/28 | 10.167.67.241 – 10.167.67.254 | 10.167.67.255 |
| 65 | 10.167.68.0/28 | 10.167.68.1 – 10.167.68.14 | 10.167.68.15 |
| 66 | 10.167.68.16/28 | 10.167.68.17 – 10.167.68.30 | 10.167.68.31 |
| 67 | 10.167.68.32/28 | 10.167.68.33 – 10.167.68.46 | 10.167.68.47 |
| 68 | 10.167.68.48/28 | 10.167.68.49 – 10.167.68.62 | 10.167.68.63 |
| 69 | 10.167.68.64/28 | 10.167.68.65 – 10.167.68.78 | 10.167.68.79 |
| 70 | 10.167.68.80/28 | 10.167.68.81 – 10.167.68.94 | 10.167.68.95 |
| 71 | 10.167.68.96/28 | 10.167.68.97 – 10.167.68.110 | 10.167.68.111 |
| 72 | 10.167.68.112/28 | 10.167.68.113 – 10.167.68.126 | 10.167.68.127 |
| 73 | 10.167.68.128/28 | 10.167.68.129 – 10.167.68.142 | 10.167.68.143 |
| 74 | 10.167.68.144/28 | 10.167.68.145 – 10.167.68.158 | 10.167.68.159 |
| 75 | 10.167.68.160/28 | 10.167.68.161 – 10.167.68.174 | 10.167.68.175 |
| 76 | 10.167.68.176/28 | 10.167.68.177 – 10.167.68.190 | 10.167.68.191 |
| 77 | 10.167.68.192/28 | 10.167.68.193 – 10.167.68.206 | 10.167.68.207 |
| 78 | 10.167.68.208/28 | 10.167.68.209 – 10.167.68.222 | 10.167.68.223 |
| 79 | 10.167.68.224/28 | 10.167.68.225 – 10.167.68.238 | 10.167.68.239 |
| 80 | 10.167.68.240/28 | 10.167.68.241 – 10.167.68.254 | 10.167.68.255 |
| 81 | 10.167.69.0/28 | 10.167.69.1 – 10.167.69.14 | 10.167.69.15 |
| 82 | 10.167.69.16/28 | 10.167.69.17 – 10.167.69.30 | 10.167.69.31 |
| 83 | 10.167.69.32/28 | 10.167.69.33 – 10.167.69.46 | 10.167.69.47 |
| 84 | 10.167.69.48/28 | 10.167.69.49 – 10.167.69.62 | 10.167.69.63 |
| 85 | 10.167.69.64/28 | 10.167.69.65 – 10.167.69.78 | 10.167.69.79 |
| 86 | 10.167.69.80/28 | 10.167.69.81 – 10.167.69.94 | 10.167.69.95 |
| 87 | 10.167.69.96/28 | 10.167.69.97 – 10.167.69.110 | 10.167.69.111 |
| 88 | 10.167.69.112/28 | 10.167.69.113 – 10.167.69.126 | 10.167.69.127 |
| 89 | 10.167.69.128/28 | 10.167.69.129 – 10.167.69.142 | 10.167.69.143 |
| 90 | 10.167.69.144/28 | 10.167.69.145 – 10.167.69.158 | 10.167.69.159 |
| 91 | 10.167.69.160/28 | 10.167.69.161 – 10.167.69.174 | 10.167.69.175 |
| 92 | 10.167.69.176/28 | 10.167.69.177 – 10.167.69.190 | 10.167.69.191 |
| 93 | 10.167.69.192/28 | 10.167.69.193 – 10.167.69.206 | 10.167.69.207 |
| 94 | 10.167.69.208/28 | 10.167.69.209 – 10.167.69.222 | 10.167.69.223 |
| 95 | 10.167.69.224/28 | 10.167.69.225 – 10.167.69.238 | 10.167.69.239 |
| 96 | 10.167.69.240/28 | 10.167.69.241 – 10.167.69.254 | 10.167.69.255 |
| 97 | 10.167.70.0/28 | 10.167.70.1 – 10.167.70.14 | 10.167.70.15 |
| 98 | 10.167.70.16/28 | 10.167.70.17 – 10.167.70.30 | 10.167.70.31 |
| 99 | 10.167.70.32/28 | 10.167.70.33 – 10.167.70.46 | 10.167.70.47 |
| 100 | 10.167.70.48/28 | 10.167.70.49 – 10.167.70.62 | 10.167.70.63 |
| 101 | 10.167.70.64/28 | 10.167.70.65 – 10.167.70.78 | 10.167.70.79 |
| 102 | 10.167.70.80/28 | 10.167.70.81 – 10.167.70.94 | 10.167.70.95 |
| 103 | 10.167.70.96/28 | 10.167.70.97 – 10.167.70.110 | 10.167.70.111 |
| 104 | 10.167.70.112/28 | 10.167.70.113 – 10.167.70.126 | 10.167.70.127 |
| 105 | 10.167.70.128/28 | 10.167.70.129 – 10.167.70.142 | 10.167.70.143 |
| 106 | 10.167.70.144/28 | 10.167.70.145 – 10.167.70.158 | 10.167.70.159 |
| 107 | 10.167.70.160/28 | 10.167.70.161 – 10.167.70.174 | 10.167.70.175 |
| 108 | 10.167.70.176/28 | 10.167.70.177 – 10.167.70.190 | 10.167.70.191 |
| 109 | 10.167.70.192/28 | 10.167.70.193 – 10.167.70.206 | 10.167.70.207 |
| 110 | 10.167.70.208/28 | 10.167.70.209 – 10.167.70.222 | 10.167.70.223 |
| 111 | 10.167.70.224/28 | 10.167.70.225 – 10.167.70.238 | 10.167.70.239 |
| 112 | 10.167.70.240/28 | 10.167.70.241 – 10.167.70.254 | 10.167.70.255 |
| 113 | 10.167.71.0/28 | 10.167.71.1 – 10.167.71.14 | 10.167.71.15 |
| 114 | 10.167.71.16/28 | 10.167.71.17 – 10.167.71.30 | 10.167.71.31 |
| 115 | 10.167.71.32/28 | 10.167.71.33 – 10.167.71.46 | 10.167.71.47 |
| 116 | 10.167.71.48/28 | 10.167.71.49 – 10.167.71.62 | 10.167.71.63 |
| 117 | 10.167.71.64/28 | 10.167.71.65 – 10.167.71.78 | 10.167.71.79 |
| 118 | 10.167.71.80/28 | 10.167.71.81 – 10.167.71.94 | 10.167.71.95 |
| 119 | 10.167.71.96/28 | 10.167.71.97 – 10.167.71.110 | 10.167.71.111 |
| 120 | 10.167.71.112/28 | 10.167.71.113 – 10.167.71.126 | 10.167.71.127 |
| 121 | 10.167.71.128/28 | 10.167.71.129 – 10.167.71.142 | 10.167.71.143 |
| 122 | 10.167.71.144/28 | 10.167.71.145 – 10.167.71.158 | 10.167.71.159 |
| 123 | 10.167.71.160/28 | 10.167.71.161 – 10.167.71.174 | 10.167.71.175 |
| 124 | 10.167.71.176/28 | 10.167.71.177 – 10.167.71.190 | 10.167.71.191 |
| 125 | 10.167.71.192/28 | 10.167.71.193 – 10.167.71.206 | 10.167.71.207 |
| 126 | 10.167.71.208/28 | 10.167.71.209 – 10.167.71.222 | 10.167.71.223 |
| 127 | 10.167.71.224/28 | 10.167.71.225 – 10.167.71.238 | 10.167.71.239 |
| 128 | 10.167.71.240/28 | 10.167.71.241 – 10.167.71.254 | 10.167.71.255 |
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.