Calculate IPv4 CIDR ranges, subnet sizes, wildcard masks, and usable host boundaries with a fast subnetting workflow.
Enter an IPv4 address and a CIDR prefix to calculate subnet boundaries, mask values, and usable host range.
Network boundaries, mask values, host counts, and binary subnet breakdown.
The IPv4 address 10.0.5.23 belongs to the 10.0.0.0/16 network, and the subnet broadcast boundary is 10.0.255.255.
This subnet provides 65,536 total addresses and 65,534 usable host addresses, with a host range from 10.0.0.1 to 10.0.255.254.
The subnet mask is 255.255.0.0, the wildcard mask is 0.0.255.255, and the address falls into Class A.
Inspect the binary representation of the IP, subnet mask, network, and broadcast values.
00001010.00000000.00000101.00010111
11111111.11111111.00000000.00000000
00001010.00000000.00000000.00000000
00001010.00000000.11111111.11111111
Useful reminders for subnetting and host calculations.
/24 means 24 network bits and 8 host bits.
Subnet mask shows the network boundary, while wildcard mask is its inverse.
/31 is commonly used for point-to-point links, while /32 represents a single-host route.
Common IPv4 subnet sizes for fast comparison without recalculating each time.
| Prefix | Subnet mask | Total addresses | Usable hosts |
|---|---|---|---|
| /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 |
| /22 | 255.255.252.0 | 1,024 | 1,022 |
| /23 | 255.255.254.0 | 512 | 510 |
| /24 | 255.255.255.0 | 256 | 254 |
| /25 | 255.255.255.128 | 128 | 126 |
| /26 | 255.255.255.192 | 64 | 62 |
| /27 | 255.255.255.224 | 32 | 30 |
| /28 | 255.255.255.240 | 16 | 14 |
| /29 | 255.255.255.248 | 8 | 6 |
| /30 | 255.255.255.252 | 4 | 2 |
| /31 | 255.255.255.254 | 2 | 2 |
| /32 | 255.255.255.255 | 1 | 1 |