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)10.12.128.0/20
network10.12.128.0/20
broadcast10.12.143.255
first host10.12.128.1
last host10.12.143.254
subnet mask255.255.240.0
wildcard0.0.15.255
addresses4,096
usable hosts4,094
classA
ipcalc 10.12.128.0/20
address00001010.00001100.10000000.00000000
subnet mask11111111.11111111.11110000.00000000
network00001010.00001100.10000000.00000000
broadcast00001010.00001100.10001111.11111111
green = network part, grey = host part
hex0x0a0c8000
decimal168591360
reverse dns0.128.12.10.in-addr.arpa
ipv4-mapped::ffff:a0c:8000
/20 split into /27 · 128 subnets
close ×| # | network | host range | broadcast |
|---|---|---|---|
| 1 | 10.12.128.0/27 | 10.12.128.1 – 10.12.128.30 | 10.12.128.31 |
| 2 | 10.12.128.32/27 | 10.12.128.33 – 10.12.128.62 | 10.12.128.63 |
| 3 | 10.12.128.64/27 | 10.12.128.65 – 10.12.128.94 | 10.12.128.95 |
| 4 | 10.12.128.96/27 | 10.12.128.97 – 10.12.128.126 | 10.12.128.127 |
| 5 | 10.12.128.128/27 | 10.12.128.129 – 10.12.128.158 | 10.12.128.159 |
| 6 | 10.12.128.160/27 | 10.12.128.161 – 10.12.128.190 | 10.12.128.191 |
| 7 | 10.12.128.192/27 | 10.12.128.193 – 10.12.128.222 | 10.12.128.223 |
| 8 | 10.12.128.224/27 | 10.12.128.225 – 10.12.128.254 | 10.12.128.255 |
| 9 | 10.12.129.0/27 | 10.12.129.1 – 10.12.129.30 | 10.12.129.31 |
| 10 | 10.12.129.32/27 | 10.12.129.33 – 10.12.129.62 | 10.12.129.63 |
| 11 | 10.12.129.64/27 | 10.12.129.65 – 10.12.129.94 | 10.12.129.95 |
| 12 | 10.12.129.96/27 | 10.12.129.97 – 10.12.129.126 | 10.12.129.127 |
| 13 | 10.12.129.128/27 | 10.12.129.129 – 10.12.129.158 | 10.12.129.159 |
| 14 | 10.12.129.160/27 | 10.12.129.161 – 10.12.129.190 | 10.12.129.191 |
| 15 | 10.12.129.192/27 | 10.12.129.193 – 10.12.129.222 | 10.12.129.223 |
| 16 | 10.12.129.224/27 | 10.12.129.225 – 10.12.129.254 | 10.12.129.255 |
| 17 | 10.12.130.0/27 | 10.12.130.1 – 10.12.130.30 | 10.12.130.31 |
| 18 | 10.12.130.32/27 | 10.12.130.33 – 10.12.130.62 | 10.12.130.63 |
| 19 | 10.12.130.64/27 | 10.12.130.65 – 10.12.130.94 | 10.12.130.95 |
| 20 | 10.12.130.96/27 | 10.12.130.97 – 10.12.130.126 | 10.12.130.127 |
| 21 | 10.12.130.128/27 | 10.12.130.129 – 10.12.130.158 | 10.12.130.159 |
| 22 | 10.12.130.160/27 | 10.12.130.161 – 10.12.130.190 | 10.12.130.191 |
| 23 | 10.12.130.192/27 | 10.12.130.193 – 10.12.130.222 | 10.12.130.223 |
| 24 | 10.12.130.224/27 | 10.12.130.225 – 10.12.130.254 | 10.12.130.255 |
| 25 | 10.12.131.0/27 | 10.12.131.1 – 10.12.131.30 | 10.12.131.31 |
| 26 | 10.12.131.32/27 | 10.12.131.33 – 10.12.131.62 | 10.12.131.63 |
| 27 | 10.12.131.64/27 | 10.12.131.65 – 10.12.131.94 | 10.12.131.95 |
| 28 | 10.12.131.96/27 | 10.12.131.97 – 10.12.131.126 | 10.12.131.127 |
| 29 | 10.12.131.128/27 | 10.12.131.129 – 10.12.131.158 | 10.12.131.159 |
| 30 | 10.12.131.160/27 | 10.12.131.161 – 10.12.131.190 | 10.12.131.191 |
| 31 | 10.12.131.192/27 | 10.12.131.193 – 10.12.131.222 | 10.12.131.223 |
| 32 | 10.12.131.224/27 | 10.12.131.225 – 10.12.131.254 | 10.12.131.255 |
| 33 | 10.12.132.0/27 | 10.12.132.1 – 10.12.132.30 | 10.12.132.31 |
| 34 | 10.12.132.32/27 | 10.12.132.33 – 10.12.132.62 | 10.12.132.63 |
| 35 | 10.12.132.64/27 | 10.12.132.65 – 10.12.132.94 | 10.12.132.95 |
| 36 | 10.12.132.96/27 | 10.12.132.97 – 10.12.132.126 | 10.12.132.127 |
| 37 | 10.12.132.128/27 | 10.12.132.129 – 10.12.132.158 | 10.12.132.159 |
| 38 | 10.12.132.160/27 | 10.12.132.161 – 10.12.132.190 | 10.12.132.191 |
| 39 | 10.12.132.192/27 | 10.12.132.193 – 10.12.132.222 | 10.12.132.223 |
| 40 | 10.12.132.224/27 | 10.12.132.225 – 10.12.132.254 | 10.12.132.255 |
| 41 | 10.12.133.0/27 | 10.12.133.1 – 10.12.133.30 | 10.12.133.31 |
| 42 | 10.12.133.32/27 | 10.12.133.33 – 10.12.133.62 | 10.12.133.63 |
| 43 | 10.12.133.64/27 | 10.12.133.65 – 10.12.133.94 | 10.12.133.95 |
| 44 | 10.12.133.96/27 | 10.12.133.97 – 10.12.133.126 | 10.12.133.127 |
| 45 | 10.12.133.128/27 | 10.12.133.129 – 10.12.133.158 | 10.12.133.159 |
| 46 | 10.12.133.160/27 | 10.12.133.161 – 10.12.133.190 | 10.12.133.191 |
| 47 | 10.12.133.192/27 | 10.12.133.193 – 10.12.133.222 | 10.12.133.223 |
| 48 | 10.12.133.224/27 | 10.12.133.225 – 10.12.133.254 | 10.12.133.255 |
| 49 | 10.12.134.0/27 | 10.12.134.1 – 10.12.134.30 | 10.12.134.31 |
| 50 | 10.12.134.32/27 | 10.12.134.33 – 10.12.134.62 | 10.12.134.63 |
| 51 | 10.12.134.64/27 | 10.12.134.65 – 10.12.134.94 | 10.12.134.95 |
| 52 | 10.12.134.96/27 | 10.12.134.97 – 10.12.134.126 | 10.12.134.127 |
| 53 | 10.12.134.128/27 | 10.12.134.129 – 10.12.134.158 | 10.12.134.159 |
| 54 | 10.12.134.160/27 | 10.12.134.161 – 10.12.134.190 | 10.12.134.191 |
| 55 | 10.12.134.192/27 | 10.12.134.193 – 10.12.134.222 | 10.12.134.223 |
| 56 | 10.12.134.224/27 | 10.12.134.225 – 10.12.134.254 | 10.12.134.255 |
| 57 | 10.12.135.0/27 | 10.12.135.1 – 10.12.135.30 | 10.12.135.31 |
| 58 | 10.12.135.32/27 | 10.12.135.33 – 10.12.135.62 | 10.12.135.63 |
| 59 | 10.12.135.64/27 | 10.12.135.65 – 10.12.135.94 | 10.12.135.95 |
| 60 | 10.12.135.96/27 | 10.12.135.97 – 10.12.135.126 | 10.12.135.127 |
| 61 | 10.12.135.128/27 | 10.12.135.129 – 10.12.135.158 | 10.12.135.159 |
| 62 | 10.12.135.160/27 | 10.12.135.161 – 10.12.135.190 | 10.12.135.191 |
| 63 | 10.12.135.192/27 | 10.12.135.193 – 10.12.135.222 | 10.12.135.223 |
| 64 | 10.12.135.224/27 | 10.12.135.225 – 10.12.135.254 | 10.12.135.255 |
| 65 | 10.12.136.0/27 | 10.12.136.1 – 10.12.136.30 | 10.12.136.31 |
| 66 | 10.12.136.32/27 | 10.12.136.33 – 10.12.136.62 | 10.12.136.63 |
| 67 | 10.12.136.64/27 | 10.12.136.65 – 10.12.136.94 | 10.12.136.95 |
| 68 | 10.12.136.96/27 | 10.12.136.97 – 10.12.136.126 | 10.12.136.127 |
| 69 | 10.12.136.128/27 | 10.12.136.129 – 10.12.136.158 | 10.12.136.159 |
| 70 | 10.12.136.160/27 | 10.12.136.161 – 10.12.136.190 | 10.12.136.191 |
| 71 | 10.12.136.192/27 | 10.12.136.193 – 10.12.136.222 | 10.12.136.223 |
| 72 | 10.12.136.224/27 | 10.12.136.225 – 10.12.136.254 | 10.12.136.255 |
| 73 | 10.12.137.0/27 | 10.12.137.1 – 10.12.137.30 | 10.12.137.31 |
| 74 | 10.12.137.32/27 | 10.12.137.33 – 10.12.137.62 | 10.12.137.63 |
| 75 | 10.12.137.64/27 | 10.12.137.65 – 10.12.137.94 | 10.12.137.95 |
| 76 | 10.12.137.96/27 | 10.12.137.97 – 10.12.137.126 | 10.12.137.127 |
| 77 | 10.12.137.128/27 | 10.12.137.129 – 10.12.137.158 | 10.12.137.159 |
| 78 | 10.12.137.160/27 | 10.12.137.161 – 10.12.137.190 | 10.12.137.191 |
| 79 | 10.12.137.192/27 | 10.12.137.193 – 10.12.137.222 | 10.12.137.223 |
| 80 | 10.12.137.224/27 | 10.12.137.225 – 10.12.137.254 | 10.12.137.255 |
| 81 | 10.12.138.0/27 | 10.12.138.1 – 10.12.138.30 | 10.12.138.31 |
| 82 | 10.12.138.32/27 | 10.12.138.33 – 10.12.138.62 | 10.12.138.63 |
| 83 | 10.12.138.64/27 | 10.12.138.65 – 10.12.138.94 | 10.12.138.95 |
| 84 | 10.12.138.96/27 | 10.12.138.97 – 10.12.138.126 | 10.12.138.127 |
| 85 | 10.12.138.128/27 | 10.12.138.129 – 10.12.138.158 | 10.12.138.159 |
| 86 | 10.12.138.160/27 | 10.12.138.161 – 10.12.138.190 | 10.12.138.191 |
| 87 | 10.12.138.192/27 | 10.12.138.193 – 10.12.138.222 | 10.12.138.223 |
| 88 | 10.12.138.224/27 | 10.12.138.225 – 10.12.138.254 | 10.12.138.255 |
| 89 | 10.12.139.0/27 | 10.12.139.1 – 10.12.139.30 | 10.12.139.31 |
| 90 | 10.12.139.32/27 | 10.12.139.33 – 10.12.139.62 | 10.12.139.63 |
| 91 | 10.12.139.64/27 | 10.12.139.65 – 10.12.139.94 | 10.12.139.95 |
| 92 | 10.12.139.96/27 | 10.12.139.97 – 10.12.139.126 | 10.12.139.127 |
| 93 | 10.12.139.128/27 | 10.12.139.129 – 10.12.139.158 | 10.12.139.159 |
| 94 | 10.12.139.160/27 | 10.12.139.161 – 10.12.139.190 | 10.12.139.191 |
| 95 | 10.12.139.192/27 | 10.12.139.193 – 10.12.139.222 | 10.12.139.223 |
| 96 | 10.12.139.224/27 | 10.12.139.225 – 10.12.139.254 | 10.12.139.255 |
| 97 | 10.12.140.0/27 | 10.12.140.1 – 10.12.140.30 | 10.12.140.31 |
| 98 | 10.12.140.32/27 | 10.12.140.33 – 10.12.140.62 | 10.12.140.63 |
| 99 | 10.12.140.64/27 | 10.12.140.65 – 10.12.140.94 | 10.12.140.95 |
| 100 | 10.12.140.96/27 | 10.12.140.97 – 10.12.140.126 | 10.12.140.127 |
| 101 | 10.12.140.128/27 | 10.12.140.129 – 10.12.140.158 | 10.12.140.159 |
| 102 | 10.12.140.160/27 | 10.12.140.161 – 10.12.140.190 | 10.12.140.191 |
| 103 | 10.12.140.192/27 | 10.12.140.193 – 10.12.140.222 | 10.12.140.223 |
| 104 | 10.12.140.224/27 | 10.12.140.225 – 10.12.140.254 | 10.12.140.255 |
| 105 | 10.12.141.0/27 | 10.12.141.1 – 10.12.141.30 | 10.12.141.31 |
| 106 | 10.12.141.32/27 | 10.12.141.33 – 10.12.141.62 | 10.12.141.63 |
| 107 | 10.12.141.64/27 | 10.12.141.65 – 10.12.141.94 | 10.12.141.95 |
| 108 | 10.12.141.96/27 | 10.12.141.97 – 10.12.141.126 | 10.12.141.127 |
| 109 | 10.12.141.128/27 | 10.12.141.129 – 10.12.141.158 | 10.12.141.159 |
| 110 | 10.12.141.160/27 | 10.12.141.161 – 10.12.141.190 | 10.12.141.191 |
| 111 | 10.12.141.192/27 | 10.12.141.193 – 10.12.141.222 | 10.12.141.223 |
| 112 | 10.12.141.224/27 | 10.12.141.225 – 10.12.141.254 | 10.12.141.255 |
| 113 | 10.12.142.0/27 | 10.12.142.1 – 10.12.142.30 | 10.12.142.31 |
| 114 | 10.12.142.32/27 | 10.12.142.33 – 10.12.142.62 | 10.12.142.63 |
| 115 | 10.12.142.64/27 | 10.12.142.65 – 10.12.142.94 | 10.12.142.95 |
| 116 | 10.12.142.96/27 | 10.12.142.97 – 10.12.142.126 | 10.12.142.127 |
| 117 | 10.12.142.128/27 | 10.12.142.129 – 10.12.142.158 | 10.12.142.159 |
| 118 | 10.12.142.160/27 | 10.12.142.161 – 10.12.142.190 | 10.12.142.191 |
| 119 | 10.12.142.192/27 | 10.12.142.193 – 10.12.142.222 | 10.12.142.223 |
| 120 | 10.12.142.224/27 | 10.12.142.225 – 10.12.142.254 | 10.12.142.255 |
| 121 | 10.12.143.0/27 | 10.12.143.1 – 10.12.143.30 | 10.12.143.31 |
| 122 | 10.12.143.32/27 | 10.12.143.33 – 10.12.143.62 | 10.12.143.63 |
| 123 | 10.12.143.64/27 | 10.12.143.65 – 10.12.143.94 | 10.12.143.95 |
| 124 | 10.12.143.96/27 | 10.12.143.97 – 10.12.143.126 | 10.12.143.127 |
| 125 | 10.12.143.128/27 | 10.12.143.129 – 10.12.143.158 | 10.12.143.159 |
| 126 | 10.12.143.160/27 | 10.12.143.161 – 10.12.143.190 | 10.12.143.191 |
| 127 | 10.12.143.192/27 | 10.12.143.193 – 10.12.143.222 | 10.12.143.223 |
| 128 | 10.12.143.224/27 | 10.12.143.225 – 10.12.143.254 | 10.12.143.255 |
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 /20 |
|---|---|---|---|---|
| /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 | 1 |
| /21 | 255.255.248.0 | 2,048 | 2,046 | 2 split → |
| /22 | 255.255.252.0 | 1,024 | 1,022 | 4 split → |
| /23 | 255.255.254.0 | 512 | 510 | 8 split → |
| /24 | 255.255.255.0 | 256 | 254 | 16 split → |
| /25 | 255.255.255.128 | 128 | 126 | 32 split → |
| /26 | 255.255.255.192 | 64 | 62 | 64 split → |
| /27 | 255.255.255.224 | 32 | 30 | 128 split → |
| /28 | 255.255.255.240 | 16 | 14 | 256 split → |
| /29 | 255.255.255.248 | 8 | 6 | 512 split → |
| /30 | 255.255.255.252 | 4 | 2 | 1,024 split → |
| /31 | 255.255.255.254 | 2 | 2 | 2,048 split → |
| /32 | 255.255.255.255 | 1 | 1 | 4,096 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.