IP Calculator
IPv4 and IPv6 subnet math, wildcard masks, CIDR helper, and IP range tools.
Calculator type
Inputs & calculate
Results
Enter values and calculate to see results.
CIDR quick reference
| CIDR | Subnet mask | Wildcard | Usable hosts |
|---|---|---|---|
| /32 | 255.255.255.255 | 0.0.0.0 | 1 |
| /30 | 255.255.255.252 | 0.0.0.3 | 2 |
| /29 | 255.255.255.248 | 0.0.0.7 | 6 |
| /28 | 255.255.255.240 | 0.0.0.15 | 14 |
| /27 | 255.255.255.224 | 0.0.0.31 | 30 |
| /26 | 255.255.255.192 | 0.0.0.63 | 62 |
| /25 | 255.255.255.128 | 0.0.0.127 | 126 |
| /24 | 255.255.255.0 | 0.0.0.255 | 254 |
| /23 | 255.255.254.0 | 0.0.1.255 | 510 |
| /22 | 255.255.252.0 | 0.0.3.255 | 1,022 |
| /21 | 255.255.248.0 | 0.0.7.255 | 2,046 |
| /20 | 255.255.240.0 | 0.0.15.255 | 4,094 |
| /16 | 255.255.0.0 | 0.0.255.255 | 65,534 |
| /8 | 255.0.0.0 | 0.255.255.255 | 16,777,214 |
/31 and /32 follow special rules; usable counts here match common exam-style defaults. Verify RFC 3021 for point-to-point /31.