Free tools
Free IP address tools
Calculators, lookups and checkers for everyday network work: subnetting, planning a /24, finding who holds an IP, checking DNS and cleaning up an IP spreadsheet. Free to use, with no sign-up.
Runs in your browser. Nothing you enter or upload is sent to us.
Calculators
IPv4 subnet calculator
Network, broadcast, usable range and masks for any block.
Open the toolIPv6 subnet calculator
First and last address, size, /64 count and reverse zone.
Open the toolSubnet mask cheat sheet
Every prefix from /8 to /32 with masks and host counts.
Open the toolCIDR and range converter
Turn first-to-last ranges into CIDR blocks, and back.
Open the toolSupernet and summarize
Merge many blocks into the shortest list for routes and ACLs.
Open the tool
Planning and checks
/24 planner
Split a /24 into customer, link and LAN blocks on a map.
Open the toolIP spreadsheet checker
Find duplicates, overlaps and typos in an Excel or CSV list.
Open the toolAddress in subnet check
Find which of your blocks holds each address.
Open the tool
Network tests
What is my IP
Your public IP address, network and reverse DNS name.
Open the toolPing
Check whether a host answers, and how fast, from a location you choose.
Open the toolTraceroute
See every network hop to a host, from a location you choose.
Open the tool
Lookups
IP lookup
Who holds an IP address: owner, ASN, country, abuse contact.
Open the toolDNS lookup
A, AAAA, MX, NS, TXT and other records for a domain.
Open the toolReverse DNS lookup
Find the PTR name for one or many IP addresses.
Open the toolFCrDNS check
Check that an IP's reverse name points back to it.
Open the toolMAC vendor lookup
Find the maker of a network device from its MAC address.
Open the tool
Your data stays with you
Nothing is sent to Helpnyx
Calculators and checkers run entirely on your own computer, and spreadsheets you open are never uploaded. Lookup tools ask public services (Cloudflare DNS and the internet registries) directly from your browser, and each one says so.
Built by an IPAM team
From the makers of IPAM Enterprise
These are the checks our portal runs every day: finding free blocks, catching overlaps and keeping /24s tidy. When a spreadsheet is no longer enough, see what the portal does.
Still tracking IPs in a spreadsheet?
IPAM Enterprise keeps every /24, block, customer and circuit in one portal, and checks each assignment for overlaps before it is saved.