All tools
All RouterFixer tools, organized by function. Everything runs in your browser, nothing to install.
IP Addressing 6 free tools
Subnet / CIDRPopular
Calculate the mask, broadcast, usable host range and CIDR notation of any IP, updating as you type. 100% in your browser.
IP AddressingMask ↔ CIDR
Convert between CIDR prefix (/24) and subnet mask (255.255.255.0) both ways, with validation.
IP AddressingIP Converter
Convert an IPv4 address between dotted decimal, binary, hexadecimal and 32-bit integer, as you type.
IP AddressingSubnet divider
Split a network into smaller subnets and see the usable range, broadcast and host count of each one.
IP AddressingWildcard / ACL
Convert a CIDR prefix into the wildcard mask used in Cisco ACLs and generate the example ACL line.
IP AddressingIPv6 expand/compress
Convert IPv6 addresses between the compressed form (::) and the full expanded form, with validation.
Diagnostics & Connection 7 free tools
Complete CheckPopular
Run the connection, latency, jitter, packet loss, DNS and public IP tests in sequence, all on one screen.
Diagnostics & ConnectionLatency & JitterPopular
Measure latency (ping), jitter and packet loss right in your browser to diagnose lag in games and video calls.
Diagnostics & ConnectionSpeed TestPopular
Measure your internet's real download, upload and ping speed, right in your browser, using the Cloudflare test server.
Diagnostics & ConnectionDNS Lookup
Look up the DNS records of any domain (A, AAAA, MX, TXT, CNAME, NS) via DNS-over-HTTPS, right in your browser.
Diagnostics & ConnectionDownload time
Calculate how long a file takes to download at your internet speed, from KB to TB, in Mbps or MB/s.
Diagnostics & ConnectionData usage
Estimate your internet usage per hour and per month for streaming, gaming, video calls and browsing.
Diagnostics & ConnectionData units
Convert between bits, bytes, KB, MB, GB, TB and the binary units KiB, MiB, GiB. Understand why KB isn't KiB.
Wi-Fi & Signal 3 free tools
Wi-Fi QR CodePopular
Create a QR code for your Wi-Fi network: point the camera and join without typing the password. Generated in your browser, nothing is sent.
Wi-Fi & SignalWi-Fi Signal (dBm)
Enter the signal value in dBm (RSSI) and see whether it's excellent, good or weak, and what to expect from the connection.
Wi-Fi & SignalWi-Fi Channels
Channel table for the 2.4 GHz, 5 GHz and 6 GHz bands, with the non-overlapping channels and which one to pick.
Email & Domain 3 free tools
SPF & DMARCPopular
Check a domain's SPF and DMARC records to see whether its email is protected against spoofing.
Email & DomainEmail validator
Validate an email address's syntax and check whether the domain has MX records able to receive messages.
Email & DomainSPF Generator
Build a valid SPF record for your domain by choosing the servers authorized to send email on your behalf.