Practical IT, Cybersecurity & AI — Explained Clearly
Use this free RAID storage calculator to find out exactly how much usable storage your drives will give you. Select your RAID level, enter your drive count and size — the results update instantly to show usable capacity, storage efficiency, fault tolerance, and whether your configuration meets the minimum drive requirements.
The right RAID level depends on what matters most to you — storage capacity, speed, or protection against drive failure.
RAID 0 gives you the most usable space and the best performance, but offers no protection at all. If one drive fails, everything is lost. Use it only for temporary or easily replaceable data.
RAID 1 mirrors your data across two or more drives. It is the simplest form of redundancy and keeps working even if half your drives fail, but you only get the capacity of one drive.
RAID 5 is the most popular choice for NAS and home lab setups. It balances capacity, speed, and redundancy — one drive can fail without data loss, and you only sacrifice one drive’s worth of capacity for parity.
RAID 6 works like RAID 5 but with two drives dedicated to parity, meaning two simultaneous drive failures are survivable. Recommended for large arrays where the risk of a second failure during a rebuild is a real concern.
RAID 10 stripes data across mirrored pairs. It offers excellent read and write performance and strong redundancy, but requires at least four drives and sacrifices half your raw capacity.
For most home lab NAS setups, RAID 5 with 4 drives is the most practical starting point. See our guide to NAS storage for more on choosing the right configuration.
S Stafford is a UK-based IT consultant and technology writer with over 30 years of hands-on experience in the industry, dating back to 1993. He specialises in cybersecurity, networking, server infrastructure, and AI tools for small and medium businesses, and writes practical guides aimed at helping UK business owners understand and implement technology confidently.
