Subnet Calculator
Calculate IPv4 networks, host ranges, and subnet masks.
Plan TTL reduction and a DNS change using explicit timestamps.
Current TTL (seconds): 86400 Planned change (ISO date with timezone): 2026-10-15T09:00:00Z Temporary TTL (seconds): 300
Use the labeled units and valid current ttl (seconds). The Example button supplies a reproducible starting input.
Calculate IPv4 networks, host ranges, and subnet masks.
Query public PTR records for an IPv4 address.
Check IPv6 address syntax, including compressed notation.
Your result will appear here.
Enter your input, then run the tool.