Free tools
Free study tools
Calculators and unlimited practice for the number-heavy topics on CompTIA A+ and CompTIA Network+. Every answer shows its working and links the standard behind it. No account needed.
All tools
- CompTIA Network+ · CompTIA A+ Core 1
IPv4 subnet calculator
Network, broadcast, usable range, and host count for any address and prefix, with the working shown. - CompTIA Network+ · CompTIA A+ Core 1
Subnetting practice
Unlimited subnetting questions. Answer, check, and see the block-size method worked through. - CompTIA A+ Core 1 · CompTIA Network+
Port and protocol reference
The well-known ports for CompTIA A+ and CompTIA Network+, each linked to its IANA registry entry. - CompTIA Network+
IPv6 compression and expansion
Shorten or expand any IPv6 address the RFC 5952 way, identify its type, and practice. - CompTIA A+ Core 1 · CompTIA Network+
Binary, decimal, and hex converter
Convert 8-bit and 16-bit values between binary, decimal, and hexadecimal, step by step. - CompTIA A+ Core 1
RAID capacity calculator
Usable space and fault tolerance for RAID 0, 1, 5, 6, and 10 with any number of equal drives.
How the tools work
Each tool runs in your browser on the same code the CertLighthouse app uses for its generated practice. The answers are computed, not looked up, so they're correct for any input, and the worked steps come from the same calculation.
Sources are IETF RFCs, the IANA registries, NIST, and vendor documentation, linked to the section that backs each rule. Nothing you type is sent anywhere.