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)10.2.32.0/21
network10.2.32.0/21
broadcast10.2.39.255
first host10.2.32.1
last host10.2.39.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.2.32.0/21
address00001010.00000010.00100000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.00000010.00100000.00000000
broadcast00001010.00000010.00100111.11111111
green = network part, grey = host part
hex0x0a022000
decimal167911424
reverse dns0.32.2.10.in-addr.arpa
ipv4-mapped::ffff:a02:2000
/21 split into /26 · 32 subnets
close ×| # | network | host range | broadcast |
|---|---|---|---|
| 1 | 10.2.32.0/26 | 10.2.32.1 – 10.2.32.62 | 10.2.32.63 |
| 2 | 10.2.32.64/26 | 10.2.32.65 – 10.2.32.126 | 10.2.32.127 |
| 3 | 10.2.32.128/26 | 10.2.32.129 – 10.2.32.190 | 10.2.32.191 |
| 4 | 10.2.32.192/26 | 10.2.32.193 – 10.2.32.254 | 10.2.32.255 |
| 5 | 10.2.33.0/26 | 10.2.33.1 – 10.2.33.62 | 10.2.33.63 |
| 6 | 10.2.33.64/26 | 10.2.33.65 – 10.2.33.126 | 10.2.33.127 |
| 7 | 10.2.33.128/26 | 10.2.33.129 – 10.2.33.190 | 10.2.33.191 |
| 8 | 10.2.33.192/26 | 10.2.33.193 – 10.2.33.254 | 10.2.33.255 |
| 9 | 10.2.34.0/26 | 10.2.34.1 – 10.2.34.62 | 10.2.34.63 |
| 10 | 10.2.34.64/26 | 10.2.34.65 – 10.2.34.126 | 10.2.34.127 |
| 11 | 10.2.34.128/26 | 10.2.34.129 – 10.2.34.190 | 10.2.34.191 |
| 12 | 10.2.34.192/26 | 10.2.34.193 – 10.2.34.254 | 10.2.34.255 |
| 13 | 10.2.35.0/26 | 10.2.35.1 – 10.2.35.62 | 10.2.35.63 |
| 14 | 10.2.35.64/26 | 10.2.35.65 – 10.2.35.126 | 10.2.35.127 |
| 15 | 10.2.35.128/26 | 10.2.35.129 – 10.2.35.190 | 10.2.35.191 |
| 16 | 10.2.35.192/26 | 10.2.35.193 – 10.2.35.254 | 10.2.35.255 |
| 17 | 10.2.36.0/26 | 10.2.36.1 – 10.2.36.62 | 10.2.36.63 |
| 18 | 10.2.36.64/26 | 10.2.36.65 – 10.2.36.126 | 10.2.36.127 |
| 19 | 10.2.36.128/26 | 10.2.36.129 – 10.2.36.190 | 10.2.36.191 |
| 20 | 10.2.36.192/26 | 10.2.36.193 – 10.2.36.254 | 10.2.36.255 |
| 21 | 10.2.37.0/26 | 10.2.37.1 – 10.2.37.62 | 10.2.37.63 |
| 22 | 10.2.37.64/26 | 10.2.37.65 – 10.2.37.126 | 10.2.37.127 |
| 23 | 10.2.37.128/26 | 10.2.37.129 – 10.2.37.190 | 10.2.37.191 |
| 24 | 10.2.37.192/26 | 10.2.37.193 – 10.2.37.254 | 10.2.37.255 |
| 25 | 10.2.38.0/26 | 10.2.38.1 – 10.2.38.62 | 10.2.38.63 |
| 26 | 10.2.38.64/26 | 10.2.38.65 – 10.2.38.126 | 10.2.38.127 |
| 27 | 10.2.38.128/26 | 10.2.38.129 – 10.2.38.190 | 10.2.38.191 |
| 28 | 10.2.38.192/26 | 10.2.38.193 – 10.2.38.254 | 10.2.38.255 |
| 29 | 10.2.39.0/26 | 10.2.39.1 – 10.2.39.62 | 10.2.39.63 |
| 30 | 10.2.39.64/26 | 10.2.39.65 – 10.2.39.126 | 10.2.39.127 |
| 31 | 10.2.39.128/26 | 10.2.39.129 – 10.2.39.190 | 10.2.39.191 |
| 32 | 10.2.39.192/26 | 10.2.39.193 – 10.2.39.254 | 10.2.39.255 |
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.