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CIDR Calculator
Calculate IP ranges, subnets, and network addressing for infrastructure planning.
CIDR Reference Table
| CIDR | Subnet Mask | Hosts | Class |
|---|---|---|---|
| /32 | 255.255.255.255 | 1 | Single host |
| /31 | 255.255.255.254 | 2 | Point-to-point |
| /30 | 255.255.255.252 | 4 (2 usable) | Point-to-point |
| /29 | 255.255.255.248 | 8 (6 usable) | Small subnet |
| /28 | 255.255.255.240 | 16 (14 usable) | Small subnet |
| /27 | 255.255.255.224 | 32 (30 usable) | Small subnet |
| /26 | 255.255.255.192 | 64 (62 usable) | Small subnet |
| /25 | 255.255.255.128 | 128 (126 usable) | Half Class C |
| /24 | 255.255.255.0 | 256 (254 usable) | Class C |
| /23 | 255.255.254.0 | 512 (510 usable) | 2x Class C |
| /22 | 255.255.252.0 | 1,024 (1,022 usable) | 4x Class C |
| /21 | 255.255.248.0 | 2,048 (2,046 usable) | 8x Class C |
| /20 | 255.255.240.0 | 4,096 (4,094 usable) | 16x Class C |
| /16 | 255.255.0.0 | 65,536 (65,534 usable) | Class B |
| /8 | 255.0.0.0 | 16,777,216 | Class A |