Network Tools
Free network utilities for IP lookup, DNS, and basic diagnostics, plus home network planning: Wi-Fi coverage and throughput, mesh nodes, Ethernet cable limits, PoE budgets, household bandwidth and file transfer time.
CIDR Overlap Checker
Compare two IPv4 or IPv6 CIDR blocks and show containment, overlap, or separation with the shared range.
IPv6 Subnet & Prefix Calculator
Calculate network boundaries, address counts, and child-prefix capacity without sending an address anywhere.
What Is My IP Address?
My IP address, instantly: your public IPv4 and IPv6 address, location, ISP, ASN, timezone, browser and screen size, with one-tap copy.
IP Subnet / CIDR Calculator
Network address, broadcast, usable hosts, masks, binary, class and subnet splitting from an IP and CIDR prefix.
CIDR to Subnet Mask Converter
Convert a CIDR prefix to a subnet mask and a mask back to a prefix, with wildcard, hex and binary forms.
Subnet Mask Cheat Sheet
All 33 IPv4 prefixes from /0 to /32 with mask, wildcard mask, total addresses and usable hosts.
Wildcard Mask Calculator
Convert a subnet mask or prefix to its wildcard mask, or a wildcard back to a mask.
How Many Hosts in a /24?
See how many usable hosts any prefix holds, or find the smallest subnet for a host count.
VLSM Calculator
Allocate different-sized subnets from one block, largest first, with masks and host ranges.
IP Address to Binary Converter
IPv4 address to dotted binary, a 32-bit string, hex and decimal.
Binary to IP Address Converter
Dotted or 32-bit binary back to an IPv4 address.
Subnet Mask to Binary Converter
Mask to binary, CIDR prefix, wildcard mask and host count.
IP Address Type Checker
Is an IPv4 or IPv6 address private, CGNAT, loopback, link-local, multicast or public? Checked against the IANA registries.
Bandwidth Delay Product Calculator: TCP Window Size
Bytes in flight from link speed and round-trip time, with the TCP window needed.
IPv4 Header Checksum Calculator
Compute or verify an IPv4 header checksum from hex or fields, with the word sum and carry folding shown.
IP Range to CIDR Converter
Convert an IPv4 range to the minimal CIDR blocks, a CIDR block to its range, or an IP to decimal, hex and binary.
IPv6 Address Validator
Check an IPv6 address, compress or expand it to the RFC 5952 form, and see its type.
IPv6 ULA Prefix Generator
Generate a random fd00::/8 unique local /48 prefix and its first /64 subnets, per RFC 4193.
SSH Key Fingerprint Calculator
SHA256 and MD5 fingerprints, key type and bit length from an OpenSSH public key. Public keys only, all in your browser.
Reverse DNS PTR Name Generator
in-addr.arpa and ip6.arpa reverse lookup names, delegation zones including RFC 2317 classless zones, and a BIND PTR record.
MAC Address Generator
Random, valid locally-administered MAC addresses in any separator and case.
MAC Address Validator
Check a MAC address format, convert between colon, hyphen and dotted forms, and decode the I/G and U/L bits.
AS Number Range Classifier
Check whether an ASN is private, documentation or reserved, and convert between asplain and asdot+.
Wi-Fi Coverage Estimator
Rough Wi-Fi range and area by band, transmit power and walls
Mesh Wi-Fi Node Count Estimator
How many mesh nodes for your floor area, floors and overlap
Ethernet Cable Length Limit Checker
100 m channel, 90 m permanent link and 10 m patch cords by category and speed
PoE Power Budget Calculator
Switch PoE budget versus device draw for af, at and bt ports
Household Bandwidth Calculator
Add streams, calls, gaming and cameras into a Mbps range
File Transfer Time Calculator
Transfer time with Ethernet/IP/TCP overhead and the TCP window latency limit
Wi-Fi Throughput Calculator
Link rate by Wi-Fi standard, channel width, streams and MCS
Network Cable Run Cost Calculator
Total cable length, spools to buy and cost for your Ethernet runs
CCTV Storage Calculator
Terabytes of disk for CCTV and IP cameras from bitrate, retention days and motion-only recording.
IP Camera Bitrate Calculator
Estimate IP camera Mbps from resolution, fps and H.264 or H.265 with an editable compression factor.
CCTV Network Bandwidth Calculator
Total camera and live-view Mbps against a switch uplink or NVR link, with headroom and most cameras that fit.
CCTV Retention Days Calculator
Days of CCTV footage a disk or NVR holds from disk size, usable share, cameras and bitrate.
PoE Camera Power Budget Calculator
Check camera watts against a PoE switch budget and 802.3af, at or bt port limits, with spare margin.
Cloud Camera Upload Bandwidth Calculator
Upload Mbps and monthly data needed for cloud or remote-viewing security cameras against your plan.
Camera Pixel Density Calculator
Pixels per metre on target from resolution, field of view and distance, with identification, recognition and observation distances.
Camera Field of View Calculator
Camera field of view angle and scene width and height at a distance from focal length and sensor size.
Motion Event Storage Calculator
Disk used by motion-triggered camera recording from events per day, clip length, buffers and bitrate.
What Is My Screen Resolution
Your screen size in pixels is shown the moment the page loads, with the pixel ratio, aspect ratio and orientation your browser reports.
What Is My Viewport Size
The width and height your browser gives this page, in CSS pixels. Drag the window edge or rotate your phone and the numbers update live.
What Is My User Agent
Your browser's User-Agent string is shown in full below, copyable in one tap, with a plain-language breakdown of what it says.
What Is My Browser
Your browser name, version and engine, read from your own browser, with a few settings that matter for support requests.
What Operating System Do I Have
Windows, macOS, Linux, Android, iOS or ChromeOS, read from your browser, with the version and CPU type when your browser shares them.
What Is My Time Zone
Your time zone name, today's UTC offset, whether daylight saving time is in effect, and a live clock, read from your device settings.
What Is My Browser Language
Your preferred language as your browser reports it, decoded from its language tag, with the full ordered list and a sample of how dates and numbers will look.
What Is My Location
Press the button and your browser will ask permission, then show your latitude, longitude and how accurate the reading is. Nothing is looked up from your IP address.
dBm to mW Converter
Convert dBm to mW, W and dBW and back.
Free Space Path Loss Calculator
FSPL in dB from distance and frequency (ITU-R P.525).
Link Budget Calculator
Received power, fade margin and max range for a radio link.
Fresnel Zone Calculator
Fresnel zone radius and 60% clearance for a radio path.
EIRP Calculator
EIRP and ERP from transmit power, cable loss and antenna gain.
LoRa Airtime Calculator
LoRa time on air by spreading factor, bandwidth and payload.
VSWR to Return Loss Calculator with Mismatch Loss
VSWR, return loss, reflection coefficient and mismatch loss.
Wi-Fi Data Rate Calculator
802.11ac and 802.11ax PHY rate by MCS, width and streams.