Subnet Calculator & Networking Tools

Enter an IP and mask or CIDR to get network address, broadcast, usable range, wildcard mask, class, and binary breakdown.

Break one network into a set of smaller, equally-sized subnets — split by new prefix length or by number of subnets needed.

Give it a list of departments and host counts; it packs right-sized subnets into your address pool as efficiently as possible.

Expand, compress, and inspect an IPv6 address and prefix — network range, address type, and total addresses.

Paste a list of known CIDR networks and check which one(s) a given IPv4 address falls inside — handy for VLAN troubleshooting.

Full /8–/32 prefix-to-mask reference table, plus the common private & reserved IPv4/IPv6 ranges.

IPv4 Address / Mask

IP Address (optionally with /CIDR)

Subnet Mask (if no /CIDR above)

Need the splitter, VLSM planner, or share links? Head to the full IPv4 Calculator page.