About NetCalc

What this is

NetCalc collects the everyday utilities a network engineer reaches for: subnet maths, VLSM allocation, IPv6 planning, CIDR conversion, wildcard masks, ACL syntax, VLAN sizing, route summarization, TCP throughput, bandwidth, DNS records, SSL certificate inspection, password entropy, and hash generation. All client-side, all free.

It also includes two practice quizzes for CCNA-level subnetting and Security+/CISSP-level hashing.

Who it is for

• Network engineers doing daily subnet maths, VLAN planning, ACL design.
• CCNA / CCNP / CISSP / Security+ candidates drilling fundamentals.
• System administrators sizing UPS budgets, planning DNS records, validating SSL certs.
• Students and instructors who want a clean reference + practice surface.

Design principles

• No account, no tracking. Calculations happen in your browser.
• Cite the standard. Where we reference behaviour, we link to the RFC, IEEE spec, NIST publication, or vendor doc.
• Fast and ad-light. Page weight kept small. Tools work on a phone.

Standards we cite

RFC 791, 1918, 3021, 4291, 5735, 6598, 7519. IEEE 802.3af / 802.3at / 802.3bt. NIST SP 800-63B. FIPS 180-4. Cisco IOS reference. Where a calculator produces a number you would defend in a design review, we make the source explicit.