Free CCNA networking tools
No account, nothing to install — the interactive tools we built to make CCNA study faster: calculators to check your work, drills to build fluency, and a live grader to prove your config works.
Subnet Calculator
Enter an IPv4 address and prefix — get the network, broadcast, host range, masks, and host count instantly.
Open →Free toolVLSM Calculator
Allocate variable-length subnets from a base network by per-subnet host requirement, largest-first.
Open →Free toolSubnetting Practice
Random CCNA-style subnetting questions, graded the instant you answer, with a streak counter.
Open →Free toolWell-Known Ports
A searchable TCP/UDP port reference — SSH 22, DNS 53, HTTPS 443 — plus a quiz to drill them.
Open →Free toolOSI Model Quiz
A protocol or device appears; you pick the right OSI layer. Instant feedback and a streak.
Open →Free toolTry the Grader
Edit a real Cisco IOS config in your browser and get instant per-requirement pass/fail.
Open →How to use these tools to study
These aren't busywork — each one targets a skill the CCNA actually tests. Use the subnet calculator to check work you first did by hand, then build speed on the subnetting practice drill until the math is automatic. The OSI model quiz and well-known ports reference lock in the fundamentals you'll lean on all exam long.
When the theory is solid, prove it on a real device: the live config grader checks an actual Cisco configuration against an answer key — the same engine behind the daily labs. Pair the tools with the free study hub for the roadmap, and when you're ready to practice for real, a subscription gives you a fresh graded lab every day.
Free tools — FAQ
Are these tools really free — do I need an account?
Yes — completely free, no account, no sign-up, no card. Every tool runs entirely in your browser, so nothing is sent to a server and you can use them as much as you like.
Which tool should I start with for the CCNA?
Start with the subnet calculator and the subnetting practice drill — subnetting is the single most-tested CCNA skill, and doing it fast by hand pays off across the whole exam. From there, the OSI model quiz and well-known ports reference lock in the fundamentals, and the live grader proves your actual Cisco config works.
Do the calculators cover IPv6 and VLSM?
The VLSM calculator handles variable-length subnetting — carving one block into right-sized subnets, exactly what the exam asks. The subnet calculator focuses on IPv4 network/broadcast/host math; for the addressing theory behind it, the study hub and concept explainers go deeper.
How is the config grader different from the calculators?
The calculators check your networking math; the grader checks a real Cisco config against an answer key, requirement by requirement — the same engine behind the daily labs. Try it free, then subscribe for a fresh graded lab every day.