Capacity before complexity
RAID Calc helps you estimate the usable capacity of RAID 0, RAID 1, RAID 5, RAID 6 and RAID 10 arrays. Enter a drive count and capacity to compare raw storage, redundancy overhead, storage efficiency and fault tolerance.
What the estimates cover
The calculator assumes equal-capacity drives. RAID 1 is limited to exactly two drives. Results describe RAID-level capacity before filesystem formatting, metadata or system reservations. Actual available space depends on your storage system and configuration.
Calculations run in your browser. No account or upload is required. This site does not model performance, rebuild times or hardware compatibility.
Use redundancy alongside backups
RAID protects against certain drive failures. It is not a substitute for separate backups of important data.
Open the RAID calculator or explore the RAID 5, RAID 6 and RAID 10 guides.