Free Network Tools
64 fast, free, no-nonsense networking tools — subnet math, IP & IPv6 converters, DNS and RDAP lookups, encoders, generators and references. Most run entirely in your browser; nothing is stored.
🧮 Subnetting & IP Math
🧮 Subnet Calculator
Network, broadcast, mask, wildcard, host range & host count from any IP/CIDR.
📏 CIDR → IP Range
Turn 10.0.0.0/8 into its first IP, last IP and total address count.
📐 IP Range → CIDR
Given a start and end IP, get the smallest set of CIDR blocks covering it.
🔃 IP Address Sorter
Sort a messy list of IPv4 addresses numerically and de-duplicate them.
🎭 Subnet Mask Converter
Convert between dotted mask, /CIDR prefix, and wildcard mask instantly.
🔟 IP → Binary
See any IPv4 address as 32 bits of binary, octet by octet.
🔢 IP → Decimal
Turn 192.168.0.1 into its 32-bit integer, and integers back into IPs.
#️⃣ IP → Hex
Convert 192.168.0.1 to 0xC0A80001 and hex back to an IP.
🧩 VLSM Calculator
Carve a network into right-sized subnets from a list of host requirements.
🏠 Hosts per Subnet
How many usable hosts are in a /24, /26, /30? Look up any prefix.
🧷 CIDR Aggregator
Merge and summarise a list of CIDRs into the fewest possible blocks.
🎯 IP-in-Subnet Checker
Is 10.0.5.7 inside 10.0.0.0/16? Check any IP against any CIDR.
🃏 Wildcard Mask Calculator
Get the wildcard (inverse) mask for any subnet mask or CIDR prefix.
🎲 Random IP Generator
Generate random IPv4/IPv6 addresses for testing, with public-only option.
⚖️ Compare Subnets
Compare two CIDRs — overlap, containment, and ranges side by side.
🔳 CIDR Visualizer
See a subnet drawn as a grid of addresses (network, hosts, broadcast).
📦 MTU / MSS Calculator
Work out TCP MSS from MTU (IPv4/IPv6), including PPPoE and tunnel overhead.
🌐 IPv6 Tools
🔬 IPv6 Expand/Compress
Expand 2001:db8::1 to full form, or compress a long IPv6 to its shortest form.
🧮 IPv6 Subnet Calculator
Prefix, first/last address and subnet counts for any IPv6 CIDR.
🔟 IPv6 → Binary
See any IPv6 address as 128 bits of binary.
🔀 IPv4 → IPv6
Turn an IPv4 into its ::ffff: mapped, compatible and 6to4 IPv6 forms.
🔄 IPv6 Reverse DNS
Build the ip6.arpa PTR name for any IPv6 address.
↩️ IPv4 Reverse DNS
Build the in-addr.arpa PTR name for any IPv4 address.
🧬 EUI-64 Calculator
Turn a MAC address into a Modified EUI-64 IPv6 interface identifier.
🔢 Converters & Encoders
🔢 Base Converter
Convert numbers between binary, decimal, hex and octal instantly.
🅱️ Base64 Encode/Decode
Encode text to Base64 and decode it back — UTF-8 safe, in-browser.
🔗 URL Encode/Decode
Percent-encode text for URLs or decode it back to plain text.
🔠 Hex ↔ Text
Convert text to hex bytes and hex back to text.
0️⃣ Text ↔ Binary
Convert text to 8-bit binary and binary back to readable text.
🔤 ASCII Table
A searchable ASCII table: decimal, hex, octal, binary and the character.
🏷️ MAC Address Formatter
Reformat a MAC between colon, hyphen, Cisco-dot and bare styles.
📋 JSON Formatter
Prettify, minify and validate JSON — 100% in your browser.
🎫 JWT Decoder
Decode a JWT's header and payload locally — nothing is uploaded.
⏱️ Unix Timestamp Converter
Convert Unix epoch seconds/millis to human time (UTC & local) and back.
⏳ Download Time Calculator
Estimate download time from file size and connection speed.
🔎 Network Lookups
📍 What Is My IP
Your public IPv4/IPv6, location, ISP and browser — looked up in your browser.
🗺️ IP Geolocation Lookup
Look up the approximate location, ISP and ASN of any public IP.
🔎 DNS Lookup
Look up A, AAAA, MX, TXT, NS, CNAME and more for any domain.
🔁 Reverse DNS Lookup
Find the hostname (PTR record) behind any IPv4 or IPv6 address.
📧 MX Record Lookup
See which mail servers handle a domain's email, with priorities.
📝 TXT Record Lookup
Read a domain's TXT records, including SPF and verification strings.
🌐 Domain RDAP Lookup
Modern WHOIS: registrar, statuses and nameservers for a domain via RDAP.
🏢 IP RDAP Lookup
Find the owning network, org and ASN for any IP via RDAP.
🏭 MAC Vendor Lookup
Identify a device's manufacturer from its MAC address (OUI).
📡 HTTP Ping Test
Measure round-trip latency to a URL from your browser (HTTP-based).
🧭 User-Agent Parser
Break down any User-Agent string into browser, OS, engine and device.
🕵️ Browser Info
See what your browser exposes: UA, OS, screen, timezone, languages…
✉️ Email Header Analyzer
Trace an email's path from raw headers: hops, delays, SPF/DKIM/DMARC.
🔓 WebRTC Leak Test
See the local IPs your browser exposes via WebRTC (even behind a VPN).
🔐 Generators & Security
🔑 Password Generator
Generate strong random passwords locally — length and character sets your call.
🆔 UUID Generator
Generate random v4 UUIDs — one or a batch — and copy them.
🔒 Hash Generator
SHA-1/256/384/512 hashes of any text, computed locally.
🎰 Random MAC Generator
Generate random MAC addresses for testing, in your preferred format.
🚪 Random Port Generator
Generate random port numbers within well-known, registered or ephemeral ranges.
🎟️ Token Generator
Generate random hex, base64url or alphanumeric tokens locally.
✍️ HMAC Generator
Compute HMAC-SHA256 (and more) of a message and key, locally.
🛡️ Password Strength Checker
Estimate a password's entropy and rough crack time, locally.
📋 References & Cheat Sheets
🚦 Common Ports
A searchable list of common TCP/UDP ports and their services.
🚥 HTTP Status Codes
Every HTTP status code, its name and meaning — searchable.
🔐 Private IP Ranges
RFC 1918 private ranges and other special IP blocks, with a live checker.
🗂️ DNS Record Types
What A, AAAA, CNAME, MX, TXT, SRV, CAA and other DNS records do.
📑 Subnetting Cheat Sheet
Every CIDR /0–/32 with mask, wildcard, block size and host count.
📶 IP Protocol Numbers
IANA IP protocol numbers: 1 ICMP, 6 TCP, 17 UDP, 47 GRE and more.
🗺️ IPv4 Address Map
Visualize all 256 IPv4 /8 blocks, colour-coded by their designation.