Slash - Subnet Calculator

About

An offline subnet calculator for CCNA, Network+, and anyone who works with IP networks day to day. This is the original Slash - the calculator I built for myself so I could check subnetting in seconds instead of doing the math by hand every time. Type it in or paste it from wherever you copied it; Slash works out the rest, all on-device. Features: - Type or paste a CIDR (192.168.1.0/24), a bare address, or a subnet mask - Slash fills in the rest - Network address, first and last host, broadcast, and where the next subnet starts - Paste straight from Cisco IOS, ifconfig, or ipconfig output and it pulls the address and mask out for you - Tap any value to copy it - "More details" opens the wildcard mask, usable host count, and a bit-by-bit binary view - Hand it just a mask and get the CIDR prefix, wildcard, and the hex netmask (the ifconfig / route-table style) - /31 point-to-point (RFC 3021) and /32 handled the way they actually behave - IPv6 when you need it, light or dark, Recents, optional haptics - Fully offline. No accounts, ads, tracking, or subscriptions. Free. - Shamelessly vibe coded using Fable 5; the subnet math lives in its own package and is hand-verified for accuracy About me: I'm a working network engineer and active CCNA, currently living in the beautifully warm state of Arizona. Questions, feedback, or a result you can't explain? Email me any time - I'm responsive, and my email actually works. Privacy: https://tylerdix.com/slash/#privacy Slash is an independent tool, not affiliated with, endorsed by, or sponsored by Cisco Systems, Inc. or CompTIA, Inc. CCNA and Network+ are trademarks of their respective owners.