RAID Storage Calculator

Calculate usable capacity, fault tolerance, parity overhead, and speed gain for RAID 0, 1, 5, 6, and 10.

RAID Storage Calculator Live Calculation
Usable Storage Capacity:
24.00 TB
Raw Total Capacity:32.00 TB
Parity Protection / Mirror:8.00 TB (25.0%)
Storage Efficiency:75.0%
Fault Tolerance:1 drive failure survived
Read Speed Multiplier:3x (theoretical estimate)
Storage Architecture Note: RAID provides system uptime and hardware disk redundancy, not an independent backup. Speed multipliers are theoretical estimates rather than guaranteed benchmark performance. A RAID array cannot protect against accidental deletion, ransomware, file corruption, power surges, or disaster. Always maintain independent external or offsite backups.

What is the RAID Storage Calculator?

Essential for NAS buyers, server builders, and IT professionals building Synology, QNAP, or TrueNAS storage pools.

How to Use This Tool

Select RAID configuration level (0, 1, 5, 6, 10), number of hard drives, and individual drive capacity in TB or GB.

Formula & Calculation Logic

The mathematical formula used to calculate this conversion is:

RAID 0: N × Capacity RAID 1: Capacity (1 drive) RAID 5: (N - 1) × Capacity RAID 6: (N - 2) × Capacity RAID 10: (N ÷ 2) × Capacity

Step-by-Step Example Calculation

Here is a real-world calculation example demonstrating the mathematics:

Example: 4 drives of 8 TB in RAID 5 Total Raw = 32 TB Usable Storage = (4 - 1) × 8 TB = 24 TB Parity Protection = 8 TB (25%) Fault Tolerance = 1 drive can fail safely

Frequently Asked Questions

RAID 5 is the most popular for 3 to 5 drives, balancing high usable storage (N-1) with single-drive fault tolerance. For 6 or more drives, RAID 6 (two drive failure protection) is recommended due to rebuild stress.

In standard hardware/software RAID, all drives will be limited to the size of the smallest disk. Systems like Synology Hybrid RAID (SHR) or unRAID allow mixed drive sizes.

NO! RAID protects against physical drive hardware failure, but does NOT protect against accidental deletion, ransomware, file corruption, or disaster. You still need an independent backup.