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)10.0.200.0/21
network10.0.200.0/21
broadcast10.0.207.255
first host10.0.200.1
last host10.0.207.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.0.200.0/21
address00001010.00000000.11001000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000000.11001000.00000000
broadcast00001010.00000000.11001111.11111111
green = network part, grey = host part
hex0x0a00c800
decimal167823360
reverse dns0.200.0.10.in-addr.arpa
ipv4-mapped::ffff:a00:c800
/21 split into /28 · 128 subnets
close ×| # | network | host range | broadcast |
|---|---|---|---|
| 1 | 10.0.200.0/28 | 10.0.200.1 – 10.0.200.14 | 10.0.200.15 |
| 2 | 10.0.200.16/28 | 10.0.200.17 – 10.0.200.30 | 10.0.200.31 |
| 3 | 10.0.200.32/28 | 10.0.200.33 – 10.0.200.46 | 10.0.200.47 |
| 4 | 10.0.200.48/28 | 10.0.200.49 – 10.0.200.62 | 10.0.200.63 |
| 5 | 10.0.200.64/28 | 10.0.200.65 – 10.0.200.78 | 10.0.200.79 |
| 6 | 10.0.200.80/28 | 10.0.200.81 – 10.0.200.94 | 10.0.200.95 |
| 7 | 10.0.200.96/28 | 10.0.200.97 – 10.0.200.110 | 10.0.200.111 |
| 8 | 10.0.200.112/28 | 10.0.200.113 – 10.0.200.126 | 10.0.200.127 |
| 9 | 10.0.200.128/28 | 10.0.200.129 – 10.0.200.142 | 10.0.200.143 |
| 10 | 10.0.200.144/28 | 10.0.200.145 – 10.0.200.158 | 10.0.200.159 |
| 11 | 10.0.200.160/28 | 10.0.200.161 – 10.0.200.174 | 10.0.200.175 |
| 12 | 10.0.200.176/28 | 10.0.200.177 – 10.0.200.190 | 10.0.200.191 |
| 13 | 10.0.200.192/28 | 10.0.200.193 – 10.0.200.206 | 10.0.200.207 |
| 14 | 10.0.200.208/28 | 10.0.200.209 – 10.0.200.222 | 10.0.200.223 |
| 15 | 10.0.200.224/28 | 10.0.200.225 – 10.0.200.238 | 10.0.200.239 |
| 16 | 10.0.200.240/28 | 10.0.200.241 – 10.0.200.254 | 10.0.200.255 |
| 17 | 10.0.201.0/28 | 10.0.201.1 – 10.0.201.14 | 10.0.201.15 |
| 18 | 10.0.201.16/28 | 10.0.201.17 – 10.0.201.30 | 10.0.201.31 |
| 19 | 10.0.201.32/28 | 10.0.201.33 – 10.0.201.46 | 10.0.201.47 |
| 20 | 10.0.201.48/28 | 10.0.201.49 – 10.0.201.62 | 10.0.201.63 |
| 21 | 10.0.201.64/28 | 10.0.201.65 – 10.0.201.78 | 10.0.201.79 |
| 22 | 10.0.201.80/28 | 10.0.201.81 – 10.0.201.94 | 10.0.201.95 |
| 23 | 10.0.201.96/28 | 10.0.201.97 – 10.0.201.110 | 10.0.201.111 |
| 24 | 10.0.201.112/28 | 10.0.201.113 – 10.0.201.126 | 10.0.201.127 |
| 25 | 10.0.201.128/28 | 10.0.201.129 – 10.0.201.142 | 10.0.201.143 |
| 26 | 10.0.201.144/28 | 10.0.201.145 – 10.0.201.158 | 10.0.201.159 |
| 27 | 10.0.201.160/28 | 10.0.201.161 – 10.0.201.174 | 10.0.201.175 |
| 28 | 10.0.201.176/28 | 10.0.201.177 – 10.0.201.190 | 10.0.201.191 |
| 29 | 10.0.201.192/28 | 10.0.201.193 – 10.0.201.206 | 10.0.201.207 |
| 30 | 10.0.201.208/28 | 10.0.201.209 – 10.0.201.222 | 10.0.201.223 |
| 31 | 10.0.201.224/28 | 10.0.201.225 – 10.0.201.238 | 10.0.201.239 |
| 32 | 10.0.201.240/28 | 10.0.201.241 – 10.0.201.254 | 10.0.201.255 |
| 33 | 10.0.202.0/28 | 10.0.202.1 – 10.0.202.14 | 10.0.202.15 |
| 34 | 10.0.202.16/28 | 10.0.202.17 – 10.0.202.30 | 10.0.202.31 |
| 35 | 10.0.202.32/28 | 10.0.202.33 – 10.0.202.46 | 10.0.202.47 |
| 36 | 10.0.202.48/28 | 10.0.202.49 – 10.0.202.62 | 10.0.202.63 |
| 37 | 10.0.202.64/28 | 10.0.202.65 – 10.0.202.78 | 10.0.202.79 |
| 38 | 10.0.202.80/28 | 10.0.202.81 – 10.0.202.94 | 10.0.202.95 |
| 39 | 10.0.202.96/28 | 10.0.202.97 – 10.0.202.110 | 10.0.202.111 |
| 40 | 10.0.202.112/28 | 10.0.202.113 – 10.0.202.126 | 10.0.202.127 |
| 41 | 10.0.202.128/28 | 10.0.202.129 – 10.0.202.142 | 10.0.202.143 |
| 42 | 10.0.202.144/28 | 10.0.202.145 – 10.0.202.158 | 10.0.202.159 |
| 43 | 10.0.202.160/28 | 10.0.202.161 – 10.0.202.174 | 10.0.202.175 |
| 44 | 10.0.202.176/28 | 10.0.202.177 – 10.0.202.190 | 10.0.202.191 |
| 45 | 10.0.202.192/28 | 10.0.202.193 – 10.0.202.206 | 10.0.202.207 |
| 46 | 10.0.202.208/28 | 10.0.202.209 – 10.0.202.222 | 10.0.202.223 |
| 47 | 10.0.202.224/28 | 10.0.202.225 – 10.0.202.238 | 10.0.202.239 |
| 48 | 10.0.202.240/28 | 10.0.202.241 – 10.0.202.254 | 10.0.202.255 |
| 49 | 10.0.203.0/28 | 10.0.203.1 – 10.0.203.14 | 10.0.203.15 |
| 50 | 10.0.203.16/28 | 10.0.203.17 – 10.0.203.30 | 10.0.203.31 |
| 51 | 10.0.203.32/28 | 10.0.203.33 – 10.0.203.46 | 10.0.203.47 |
| 52 | 10.0.203.48/28 | 10.0.203.49 – 10.0.203.62 | 10.0.203.63 |
| 53 | 10.0.203.64/28 | 10.0.203.65 – 10.0.203.78 | 10.0.203.79 |
| 54 | 10.0.203.80/28 | 10.0.203.81 – 10.0.203.94 | 10.0.203.95 |
| 55 | 10.0.203.96/28 | 10.0.203.97 – 10.0.203.110 | 10.0.203.111 |
| 56 | 10.0.203.112/28 | 10.0.203.113 – 10.0.203.126 | 10.0.203.127 |
| 57 | 10.0.203.128/28 | 10.0.203.129 – 10.0.203.142 | 10.0.203.143 |
| 58 | 10.0.203.144/28 | 10.0.203.145 – 10.0.203.158 | 10.0.203.159 |
| 59 | 10.0.203.160/28 | 10.0.203.161 – 10.0.203.174 | 10.0.203.175 |
| 60 | 10.0.203.176/28 | 10.0.203.177 – 10.0.203.190 | 10.0.203.191 |
| 61 | 10.0.203.192/28 | 10.0.203.193 – 10.0.203.206 | 10.0.203.207 |
| 62 | 10.0.203.208/28 | 10.0.203.209 – 10.0.203.222 | 10.0.203.223 |
| 63 | 10.0.203.224/28 | 10.0.203.225 – 10.0.203.238 | 10.0.203.239 |
| 64 | 10.0.203.240/28 | 10.0.203.241 – 10.0.203.254 | 10.0.203.255 |
| 65 | 10.0.204.0/28 | 10.0.204.1 – 10.0.204.14 | 10.0.204.15 |
| 66 | 10.0.204.16/28 | 10.0.204.17 – 10.0.204.30 | 10.0.204.31 |
| 67 | 10.0.204.32/28 | 10.0.204.33 – 10.0.204.46 | 10.0.204.47 |
| 68 | 10.0.204.48/28 | 10.0.204.49 – 10.0.204.62 | 10.0.204.63 |
| 69 | 10.0.204.64/28 | 10.0.204.65 – 10.0.204.78 | 10.0.204.79 |
| 70 | 10.0.204.80/28 | 10.0.204.81 – 10.0.204.94 | 10.0.204.95 |
| 71 | 10.0.204.96/28 | 10.0.204.97 – 10.0.204.110 | 10.0.204.111 |
| 72 | 10.0.204.112/28 | 10.0.204.113 – 10.0.204.126 | 10.0.204.127 |
| 73 | 10.0.204.128/28 | 10.0.204.129 – 10.0.204.142 | 10.0.204.143 |
| 74 | 10.0.204.144/28 | 10.0.204.145 – 10.0.204.158 | 10.0.204.159 |
| 75 | 10.0.204.160/28 | 10.0.204.161 – 10.0.204.174 | 10.0.204.175 |
| 76 | 10.0.204.176/28 | 10.0.204.177 – 10.0.204.190 | 10.0.204.191 |
| 77 | 10.0.204.192/28 | 10.0.204.193 – 10.0.204.206 | 10.0.204.207 |
| 78 | 10.0.204.208/28 | 10.0.204.209 – 10.0.204.222 | 10.0.204.223 |
| 79 | 10.0.204.224/28 | 10.0.204.225 – 10.0.204.238 | 10.0.204.239 |
| 80 | 10.0.204.240/28 | 10.0.204.241 – 10.0.204.254 | 10.0.204.255 |
| 81 | 10.0.205.0/28 | 10.0.205.1 – 10.0.205.14 | 10.0.205.15 |
| 82 | 10.0.205.16/28 | 10.0.205.17 – 10.0.205.30 | 10.0.205.31 |
| 83 | 10.0.205.32/28 | 10.0.205.33 – 10.0.205.46 | 10.0.205.47 |
| 84 | 10.0.205.48/28 | 10.0.205.49 – 10.0.205.62 | 10.0.205.63 |
| 85 | 10.0.205.64/28 | 10.0.205.65 – 10.0.205.78 | 10.0.205.79 |
| 86 | 10.0.205.80/28 | 10.0.205.81 – 10.0.205.94 | 10.0.205.95 |
| 87 | 10.0.205.96/28 | 10.0.205.97 – 10.0.205.110 | 10.0.205.111 |
| 88 | 10.0.205.112/28 | 10.0.205.113 – 10.0.205.126 | 10.0.205.127 |
| 89 | 10.0.205.128/28 | 10.0.205.129 – 10.0.205.142 | 10.0.205.143 |
| 90 | 10.0.205.144/28 | 10.0.205.145 – 10.0.205.158 | 10.0.205.159 |
| 91 | 10.0.205.160/28 | 10.0.205.161 – 10.0.205.174 | 10.0.205.175 |
| 92 | 10.0.205.176/28 | 10.0.205.177 – 10.0.205.190 | 10.0.205.191 |
| 93 | 10.0.205.192/28 | 10.0.205.193 – 10.0.205.206 | 10.0.205.207 |
| 94 | 10.0.205.208/28 | 10.0.205.209 – 10.0.205.222 | 10.0.205.223 |
| 95 | 10.0.205.224/28 | 10.0.205.225 – 10.0.205.238 | 10.0.205.239 |
| 96 | 10.0.205.240/28 | 10.0.205.241 – 10.0.205.254 | 10.0.205.255 |
| 97 | 10.0.206.0/28 | 10.0.206.1 – 10.0.206.14 | 10.0.206.15 |
| 98 | 10.0.206.16/28 | 10.0.206.17 – 10.0.206.30 | 10.0.206.31 |
| 99 | 10.0.206.32/28 | 10.0.206.33 – 10.0.206.46 | 10.0.206.47 |
| 100 | 10.0.206.48/28 | 10.0.206.49 – 10.0.206.62 | 10.0.206.63 |
| 101 | 10.0.206.64/28 | 10.0.206.65 – 10.0.206.78 | 10.0.206.79 |
| 102 | 10.0.206.80/28 | 10.0.206.81 – 10.0.206.94 | 10.0.206.95 |
| 103 | 10.0.206.96/28 | 10.0.206.97 – 10.0.206.110 | 10.0.206.111 |
| 104 | 10.0.206.112/28 | 10.0.206.113 – 10.0.206.126 | 10.0.206.127 |
| 105 | 10.0.206.128/28 | 10.0.206.129 – 10.0.206.142 | 10.0.206.143 |
| 106 | 10.0.206.144/28 | 10.0.206.145 – 10.0.206.158 | 10.0.206.159 |
| 107 | 10.0.206.160/28 | 10.0.206.161 – 10.0.206.174 | 10.0.206.175 |
| 108 | 10.0.206.176/28 | 10.0.206.177 – 10.0.206.190 | 10.0.206.191 |
| 109 | 10.0.206.192/28 | 10.0.206.193 – 10.0.206.206 | 10.0.206.207 |
| 110 | 10.0.206.208/28 | 10.0.206.209 – 10.0.206.222 | 10.0.206.223 |
| 111 | 10.0.206.224/28 | 10.0.206.225 – 10.0.206.238 | 10.0.206.239 |
| 112 | 10.0.206.240/28 | 10.0.206.241 – 10.0.206.254 | 10.0.206.255 |
| 113 | 10.0.207.0/28 | 10.0.207.1 – 10.0.207.14 | 10.0.207.15 |
| 114 | 10.0.207.16/28 | 10.0.207.17 – 10.0.207.30 | 10.0.207.31 |
| 115 | 10.0.207.32/28 | 10.0.207.33 – 10.0.207.46 | 10.0.207.47 |
| 116 | 10.0.207.48/28 | 10.0.207.49 – 10.0.207.62 | 10.0.207.63 |
| 117 | 10.0.207.64/28 | 10.0.207.65 – 10.0.207.78 | 10.0.207.79 |
| 118 | 10.0.207.80/28 | 10.0.207.81 – 10.0.207.94 | 10.0.207.95 |
| 119 | 10.0.207.96/28 | 10.0.207.97 – 10.0.207.110 | 10.0.207.111 |
| 120 | 10.0.207.112/28 | 10.0.207.113 – 10.0.207.126 | 10.0.207.127 |
| 121 | 10.0.207.128/28 | 10.0.207.129 – 10.0.207.142 | 10.0.207.143 |
| 122 | 10.0.207.144/28 | 10.0.207.145 – 10.0.207.158 | 10.0.207.159 |
| 123 | 10.0.207.160/28 | 10.0.207.161 – 10.0.207.174 | 10.0.207.175 |
| 124 | 10.0.207.176/28 | 10.0.207.177 – 10.0.207.190 | 10.0.207.191 |
| 125 | 10.0.207.192/28 | 10.0.207.193 – 10.0.207.206 | 10.0.207.207 |
| 126 | 10.0.207.208/28 | 10.0.207.209 – 10.0.207.222 | 10.0.207.223 |
| 127 | 10.0.207.224/28 | 10.0.207.225 – 10.0.207.238 | 10.0.207.239 |
| 128 | 10.0.207.240/28 | 10.0.207.241 – 10.0.207.254 | 10.0.207.255 |
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.