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)10.4.152.0/21
network10.4.152.0/21
broadcast10.4.159.255
first host10.4.152.1
last host10.4.159.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.4.152.0/21
address00001010.00000100.10011000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000100.10011000.00000000
broadcast00001010.00000100.10011111.11111111
green = network part, grey = host part
hex0x0a049800
decimal168073216
reverse dns0.152.4.10.in-addr.arpa
ipv4-mapped::ffff:a04:9800
/21 split into /28 · 128 subnets
close ×| # | network | host range | broadcast |
|---|---|---|---|
| 1 | 10.4.152.0/28 | 10.4.152.1 – 10.4.152.14 | 10.4.152.15 |
| 2 | 10.4.152.16/28 | 10.4.152.17 – 10.4.152.30 | 10.4.152.31 |
| 3 | 10.4.152.32/28 | 10.4.152.33 – 10.4.152.46 | 10.4.152.47 |
| 4 | 10.4.152.48/28 | 10.4.152.49 – 10.4.152.62 | 10.4.152.63 |
| 5 | 10.4.152.64/28 | 10.4.152.65 – 10.4.152.78 | 10.4.152.79 |
| 6 | 10.4.152.80/28 | 10.4.152.81 – 10.4.152.94 | 10.4.152.95 |
| 7 | 10.4.152.96/28 | 10.4.152.97 – 10.4.152.110 | 10.4.152.111 |
| 8 | 10.4.152.112/28 | 10.4.152.113 – 10.4.152.126 | 10.4.152.127 |
| 9 | 10.4.152.128/28 | 10.4.152.129 – 10.4.152.142 | 10.4.152.143 |
| 10 | 10.4.152.144/28 | 10.4.152.145 – 10.4.152.158 | 10.4.152.159 |
| 11 | 10.4.152.160/28 | 10.4.152.161 – 10.4.152.174 | 10.4.152.175 |
| 12 | 10.4.152.176/28 | 10.4.152.177 – 10.4.152.190 | 10.4.152.191 |
| 13 | 10.4.152.192/28 | 10.4.152.193 – 10.4.152.206 | 10.4.152.207 |
| 14 | 10.4.152.208/28 | 10.4.152.209 – 10.4.152.222 | 10.4.152.223 |
| 15 | 10.4.152.224/28 | 10.4.152.225 – 10.4.152.238 | 10.4.152.239 |
| 16 | 10.4.152.240/28 | 10.4.152.241 – 10.4.152.254 | 10.4.152.255 |
| 17 | 10.4.153.0/28 | 10.4.153.1 – 10.4.153.14 | 10.4.153.15 |
| 18 | 10.4.153.16/28 | 10.4.153.17 – 10.4.153.30 | 10.4.153.31 |
| 19 | 10.4.153.32/28 | 10.4.153.33 – 10.4.153.46 | 10.4.153.47 |
| 20 | 10.4.153.48/28 | 10.4.153.49 – 10.4.153.62 | 10.4.153.63 |
| 21 | 10.4.153.64/28 | 10.4.153.65 – 10.4.153.78 | 10.4.153.79 |
| 22 | 10.4.153.80/28 | 10.4.153.81 – 10.4.153.94 | 10.4.153.95 |
| 23 | 10.4.153.96/28 | 10.4.153.97 – 10.4.153.110 | 10.4.153.111 |
| 24 | 10.4.153.112/28 | 10.4.153.113 – 10.4.153.126 | 10.4.153.127 |
| 25 | 10.4.153.128/28 | 10.4.153.129 – 10.4.153.142 | 10.4.153.143 |
| 26 | 10.4.153.144/28 | 10.4.153.145 – 10.4.153.158 | 10.4.153.159 |
| 27 | 10.4.153.160/28 | 10.4.153.161 – 10.4.153.174 | 10.4.153.175 |
| 28 | 10.4.153.176/28 | 10.4.153.177 – 10.4.153.190 | 10.4.153.191 |
| 29 | 10.4.153.192/28 | 10.4.153.193 – 10.4.153.206 | 10.4.153.207 |
| 30 | 10.4.153.208/28 | 10.4.153.209 – 10.4.153.222 | 10.4.153.223 |
| 31 | 10.4.153.224/28 | 10.4.153.225 – 10.4.153.238 | 10.4.153.239 |
| 32 | 10.4.153.240/28 | 10.4.153.241 – 10.4.153.254 | 10.4.153.255 |
| 33 | 10.4.154.0/28 | 10.4.154.1 – 10.4.154.14 | 10.4.154.15 |
| 34 | 10.4.154.16/28 | 10.4.154.17 – 10.4.154.30 | 10.4.154.31 |
| 35 | 10.4.154.32/28 | 10.4.154.33 – 10.4.154.46 | 10.4.154.47 |
| 36 | 10.4.154.48/28 | 10.4.154.49 – 10.4.154.62 | 10.4.154.63 |
| 37 | 10.4.154.64/28 | 10.4.154.65 – 10.4.154.78 | 10.4.154.79 |
| 38 | 10.4.154.80/28 | 10.4.154.81 – 10.4.154.94 | 10.4.154.95 |
| 39 | 10.4.154.96/28 | 10.4.154.97 – 10.4.154.110 | 10.4.154.111 |
| 40 | 10.4.154.112/28 | 10.4.154.113 – 10.4.154.126 | 10.4.154.127 |
| 41 | 10.4.154.128/28 | 10.4.154.129 – 10.4.154.142 | 10.4.154.143 |
| 42 | 10.4.154.144/28 | 10.4.154.145 – 10.4.154.158 | 10.4.154.159 |
| 43 | 10.4.154.160/28 | 10.4.154.161 – 10.4.154.174 | 10.4.154.175 |
| 44 | 10.4.154.176/28 | 10.4.154.177 – 10.4.154.190 | 10.4.154.191 |
| 45 | 10.4.154.192/28 | 10.4.154.193 – 10.4.154.206 | 10.4.154.207 |
| 46 | 10.4.154.208/28 | 10.4.154.209 – 10.4.154.222 | 10.4.154.223 |
| 47 | 10.4.154.224/28 | 10.4.154.225 – 10.4.154.238 | 10.4.154.239 |
| 48 | 10.4.154.240/28 | 10.4.154.241 – 10.4.154.254 | 10.4.154.255 |
| 49 | 10.4.155.0/28 | 10.4.155.1 – 10.4.155.14 | 10.4.155.15 |
| 50 | 10.4.155.16/28 | 10.4.155.17 – 10.4.155.30 | 10.4.155.31 |
| 51 | 10.4.155.32/28 | 10.4.155.33 – 10.4.155.46 | 10.4.155.47 |
| 52 | 10.4.155.48/28 | 10.4.155.49 – 10.4.155.62 | 10.4.155.63 |
| 53 | 10.4.155.64/28 | 10.4.155.65 – 10.4.155.78 | 10.4.155.79 |
| 54 | 10.4.155.80/28 | 10.4.155.81 – 10.4.155.94 | 10.4.155.95 |
| 55 | 10.4.155.96/28 | 10.4.155.97 – 10.4.155.110 | 10.4.155.111 |
| 56 | 10.4.155.112/28 | 10.4.155.113 – 10.4.155.126 | 10.4.155.127 |
| 57 | 10.4.155.128/28 | 10.4.155.129 – 10.4.155.142 | 10.4.155.143 |
| 58 | 10.4.155.144/28 | 10.4.155.145 – 10.4.155.158 | 10.4.155.159 |
| 59 | 10.4.155.160/28 | 10.4.155.161 – 10.4.155.174 | 10.4.155.175 |
| 60 | 10.4.155.176/28 | 10.4.155.177 – 10.4.155.190 | 10.4.155.191 |
| 61 | 10.4.155.192/28 | 10.4.155.193 – 10.4.155.206 | 10.4.155.207 |
| 62 | 10.4.155.208/28 | 10.4.155.209 – 10.4.155.222 | 10.4.155.223 |
| 63 | 10.4.155.224/28 | 10.4.155.225 – 10.4.155.238 | 10.4.155.239 |
| 64 | 10.4.155.240/28 | 10.4.155.241 – 10.4.155.254 | 10.4.155.255 |
| 65 | 10.4.156.0/28 | 10.4.156.1 – 10.4.156.14 | 10.4.156.15 |
| 66 | 10.4.156.16/28 | 10.4.156.17 – 10.4.156.30 | 10.4.156.31 |
| 67 | 10.4.156.32/28 | 10.4.156.33 – 10.4.156.46 | 10.4.156.47 |
| 68 | 10.4.156.48/28 | 10.4.156.49 – 10.4.156.62 | 10.4.156.63 |
| 69 | 10.4.156.64/28 | 10.4.156.65 – 10.4.156.78 | 10.4.156.79 |
| 70 | 10.4.156.80/28 | 10.4.156.81 – 10.4.156.94 | 10.4.156.95 |
| 71 | 10.4.156.96/28 | 10.4.156.97 – 10.4.156.110 | 10.4.156.111 |
| 72 | 10.4.156.112/28 | 10.4.156.113 – 10.4.156.126 | 10.4.156.127 |
| 73 | 10.4.156.128/28 | 10.4.156.129 – 10.4.156.142 | 10.4.156.143 |
| 74 | 10.4.156.144/28 | 10.4.156.145 – 10.4.156.158 | 10.4.156.159 |
| 75 | 10.4.156.160/28 | 10.4.156.161 – 10.4.156.174 | 10.4.156.175 |
| 76 | 10.4.156.176/28 | 10.4.156.177 – 10.4.156.190 | 10.4.156.191 |
| 77 | 10.4.156.192/28 | 10.4.156.193 – 10.4.156.206 | 10.4.156.207 |
| 78 | 10.4.156.208/28 | 10.4.156.209 – 10.4.156.222 | 10.4.156.223 |
| 79 | 10.4.156.224/28 | 10.4.156.225 – 10.4.156.238 | 10.4.156.239 |
| 80 | 10.4.156.240/28 | 10.4.156.241 – 10.4.156.254 | 10.4.156.255 |
| 81 | 10.4.157.0/28 | 10.4.157.1 – 10.4.157.14 | 10.4.157.15 |
| 82 | 10.4.157.16/28 | 10.4.157.17 – 10.4.157.30 | 10.4.157.31 |
| 83 | 10.4.157.32/28 | 10.4.157.33 – 10.4.157.46 | 10.4.157.47 |
| 84 | 10.4.157.48/28 | 10.4.157.49 – 10.4.157.62 | 10.4.157.63 |
| 85 | 10.4.157.64/28 | 10.4.157.65 – 10.4.157.78 | 10.4.157.79 |
| 86 | 10.4.157.80/28 | 10.4.157.81 – 10.4.157.94 | 10.4.157.95 |
| 87 | 10.4.157.96/28 | 10.4.157.97 – 10.4.157.110 | 10.4.157.111 |
| 88 | 10.4.157.112/28 | 10.4.157.113 – 10.4.157.126 | 10.4.157.127 |
| 89 | 10.4.157.128/28 | 10.4.157.129 – 10.4.157.142 | 10.4.157.143 |
| 90 | 10.4.157.144/28 | 10.4.157.145 – 10.4.157.158 | 10.4.157.159 |
| 91 | 10.4.157.160/28 | 10.4.157.161 – 10.4.157.174 | 10.4.157.175 |
| 92 | 10.4.157.176/28 | 10.4.157.177 – 10.4.157.190 | 10.4.157.191 |
| 93 | 10.4.157.192/28 | 10.4.157.193 – 10.4.157.206 | 10.4.157.207 |
| 94 | 10.4.157.208/28 | 10.4.157.209 – 10.4.157.222 | 10.4.157.223 |
| 95 | 10.4.157.224/28 | 10.4.157.225 – 10.4.157.238 | 10.4.157.239 |
| 96 | 10.4.157.240/28 | 10.4.157.241 – 10.4.157.254 | 10.4.157.255 |
| 97 | 10.4.158.0/28 | 10.4.158.1 – 10.4.158.14 | 10.4.158.15 |
| 98 | 10.4.158.16/28 | 10.4.158.17 – 10.4.158.30 | 10.4.158.31 |
| 99 | 10.4.158.32/28 | 10.4.158.33 – 10.4.158.46 | 10.4.158.47 |
| 100 | 10.4.158.48/28 | 10.4.158.49 – 10.4.158.62 | 10.4.158.63 |
| 101 | 10.4.158.64/28 | 10.4.158.65 – 10.4.158.78 | 10.4.158.79 |
| 102 | 10.4.158.80/28 | 10.4.158.81 – 10.4.158.94 | 10.4.158.95 |
| 103 | 10.4.158.96/28 | 10.4.158.97 – 10.4.158.110 | 10.4.158.111 |
| 104 | 10.4.158.112/28 | 10.4.158.113 – 10.4.158.126 | 10.4.158.127 |
| 105 | 10.4.158.128/28 | 10.4.158.129 – 10.4.158.142 | 10.4.158.143 |
| 106 | 10.4.158.144/28 | 10.4.158.145 – 10.4.158.158 | 10.4.158.159 |
| 107 | 10.4.158.160/28 | 10.4.158.161 – 10.4.158.174 | 10.4.158.175 |
| 108 | 10.4.158.176/28 | 10.4.158.177 – 10.4.158.190 | 10.4.158.191 |
| 109 | 10.4.158.192/28 | 10.4.158.193 – 10.4.158.206 | 10.4.158.207 |
| 110 | 10.4.158.208/28 | 10.4.158.209 – 10.4.158.222 | 10.4.158.223 |
| 111 | 10.4.158.224/28 | 10.4.158.225 – 10.4.158.238 | 10.4.158.239 |
| 112 | 10.4.158.240/28 | 10.4.158.241 – 10.4.158.254 | 10.4.158.255 |
| 113 | 10.4.159.0/28 | 10.4.159.1 – 10.4.159.14 | 10.4.159.15 |
| 114 | 10.4.159.16/28 | 10.4.159.17 – 10.4.159.30 | 10.4.159.31 |
| 115 | 10.4.159.32/28 | 10.4.159.33 – 10.4.159.46 | 10.4.159.47 |
| 116 | 10.4.159.48/28 | 10.4.159.49 – 10.4.159.62 | 10.4.159.63 |
| 117 | 10.4.159.64/28 | 10.4.159.65 – 10.4.159.78 | 10.4.159.79 |
| 118 | 10.4.159.80/28 | 10.4.159.81 – 10.4.159.94 | 10.4.159.95 |
| 119 | 10.4.159.96/28 | 10.4.159.97 – 10.4.159.110 | 10.4.159.111 |
| 120 | 10.4.159.112/28 | 10.4.159.113 – 10.4.159.126 | 10.4.159.127 |
| 121 | 10.4.159.128/28 | 10.4.159.129 – 10.4.159.142 | 10.4.159.143 |
| 122 | 10.4.159.144/28 | 10.4.159.145 – 10.4.159.158 | 10.4.159.159 |
| 123 | 10.4.159.160/28 | 10.4.159.161 – 10.4.159.174 | 10.4.159.175 |
| 124 | 10.4.159.176/28 | 10.4.159.177 – 10.4.159.190 | 10.4.159.191 |
| 125 | 10.4.159.192/28 | 10.4.159.193 – 10.4.159.206 | 10.4.159.207 |
| 126 | 10.4.159.208/28 | 10.4.159.209 – 10.4.159.222 | 10.4.159.223 |
| 127 | 10.4.159.224/28 | 10.4.159.225 – 10.4.159.238 | 10.4.159.239 |
| 128 | 10.4.159.240/28 | 10.4.159.241 – 10.4.159.254 | 10.4.159.255 |
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.