CIDR Subnet CalculatorIPv4 / IPv6 Supported
Instantly calculate network details (ranges, host counts, etc.) from an IP address and prefix length.
πView IPv4 / IPv6 Common Prefixes Cheat Sheet
IPv4: Private IP Ranges and Common Prefixes
IP ranges for private networks not routed on the internet, and commonly used allocation sizes.
- β’Class A:
10.0.0.0/8 - β’Class B:
172.16.0.0/12 - β’Class C:
192.168.0.0/16 - β’
/24(255.255.255.0): Usable IPs: 254. The most standard and intuitive basic unit for small to medium networks. - β’
/28(255.255.255.240): Usable IPs: 14. Used for limited purposes such as load balancers or small DMZs. - β’
/31(RFC 3021): Point-to-Point only. Prevents address exhaustion in environments with only two devices like router-to-router connections. - β’
/32: Specifies a single host (the exact IP address itself).
IPv6: Common Prefixes and Subnetting
With IPv6, host exhaustion is rarely a concern. Usually, an ISP assigns a /48 or /56, which is then divided into /64 subnets for internal networks.
- β’
/48: Standard allocation for enterprises. Can create 65,536 internal/64subnets. - β’
/56: Allocation for small sites or residential users. Can create 256 internal/64subnets. - β’
/64: Standard subnet size for a single LAN segment (e.g., VLAN). Required for SLAAC (Stateless Address Autoconfiguration). - β’
/127(RFC 6164): Dedicated for Point-to-Point router links. Equivalent to IPv4/31. - β’
/128: Specifies a single host (equivalent to IPv4/32).
Configuration Parameters
IPv4
/
Analysis Results
192.168.1.0/24
IPv4 Subnet
| IP Address | 192.168.1.0 | |
|---|---|---|
| Network Address | 192.168.1.0 | |
| Broadcast Address | 192.168.1.255 | |
| First Assignable IP | 192.168.1.1 | |
| Last Assignable IP | 192.168.1.254 | |
| Subnet Mask | 255.255.255.0 | |
| Wildcard Mask | 0.0.0.255 | |
| Usable IPs | 254 | |
| * Prefixes /31 and /32 are calculated based on Point-to-Point links (RFC 3021). | ||
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