RAID 0/1/5/6/10 Capacity Calculator

Calculate usable storage, parity loss, disk efficiency, and fault tolerance across RAID 0, 1, 5, 6, 10, 50, and 60 configurations.

Input Parameters

Try Example:

Calculation Results

drives: 4
driveSize: 2
unit: TB
raidType: RAID5
hotSpares: 0
rawTotalTB: 8
rawTotalTiB: 7.28
usableTB: 6
usableTiB: 5.46
parityLossTB: 2
parityLossTiB: 1.82
storageEfficiencyPct: 75
faultToleranceText: 1 drive bersamaan
speedReadGain: 3×
speedWriteGain: 1× (Parity write penalty)
warningMessage: undefined

How to Use This Tool

Select your target RAID level (RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, RAID 50, or RAID 60).
Enter the number of physical disk drives, individual disk capacity (TB or GB), and any dedicated Hot Spare drives.
Review the net usable capacity in TB and TiB, storage efficiency percentage, parity overhead, and hardware fault tolerance limits.

Worked Example: Standard Server RAID 5 (4 × 2 TB)

Computed example: An array of 4 drives × 2 TB (8 TB / 7.28 TiB raw) in RAID5 provides 6 TB (5.46 TiB) net usable storage with 75% storage efficiency, 2 TB parity overhead, and 1 drive bersamaan fault tolerance.

Example Input

{
  "drives": 4,
  "driveSize": 2,
  "unit": "TB",
  "raidType": "raid5",
  "hotSpares": 0
}

Calculated Output

drives:: 4
driveSize:: 2
unit:: TB
raidType:: RAID5
hotSpares:: 0
rawTotalTB:: 8
rawTotalTiB:: 7.28
usableTB:: 6
usableTiB:: 5.46
parityLossTB:: 2
parityLossTiB:: 1.82
storageEfficiencyPct:: 75
faultToleranceText:: 1 drive bersamaan
speedReadGain:: 3×
speedWriteGain:: 1× (Parity write penalty)
warningMessage:: undefined

Core Concept & Engineering Notes

Redundant Array of Independent Disks (RAID) aggregates multiple physical hard drives or solid-state drives into a single logical volume to deliver fault tolerance against hardware failures, improve read/write I/O performance, or achieve both concurrently. Sizing storage arrays and selecting the appropriate RAID level is a critical architecture milestone for systems administrators, directly dictating storage efficiency ratios, disk failure resilience, and I/O write penalties. RAID 0 (Striping) distributes data evenly across member disks without parity or mirroring, offering maximum throughput and 100% capacity utilization at the severe cost of zero fault tolerance—a single drive failure destroys the entire array. RAID 1 (Mirroring) creates duplicate copies across paired disks, delivering high read throughput and simple fault recovery at 50% storage efficiency. RAID 5 introduces distributed parity across three or more disks, withstanding a single drive loss while providing (N-1)/N capacity. With modern high-capacity drives (exceeding 4 TB), RAID 6 (Dual Parity) is strongly preferred over RAID 5 because its dual parity blocks safeguard against a catastrophic second disk failure during intensive, multi-hour rebuild operations. For I/O-intensive workloads such as transactional enterprise databases and virtual machine hypervisors, nested RAID 10 (Striping of Mirrors) provides optimal write throughput and fast rebuild times by eliminating parity calculation bottlenecks. This calculator evaluates gross raw capacity in decimal TB and binary TiB, net usable storage capacity, parity and spare disk consumption, overall storage efficiency percentages, and fault tolerance thresholds across all primary RAID topologies.

How It Was Calculated (Formulas & Steps)

Mathematical Formulas

RAID 0 Usable = N × Size (100% Efficiency)
RAID 1 Usable = 1 × Size (50% Efficiency for 2 drives)
RAID 5 Usable = (N − 1 − HotSpare) × Size
RAID 6 Usable = (N − 2 − HotSpare) × Size
RAID 10 Usable = floor((N − HotSpare) ÷ 2) × Size
RAID 50 Usable = (N − 2 − HotSpare) × Size (2 sub-arrays)
RAID 60 Usable = (N − 4 − HotSpare) × Size (2 sub-arrays)
Binary TiB = Decimal TB × 0.9094947

Step-by-Step Calculation

Total raw array capacity: 4 drives × 2 TB = 8 TB (7.28 TiB)
RAID5 allocation: 3 effective data drives, 1 parity/mirror/spare drives
Net usable capacity: 6 TB (5.46 TiB) with 75% storage efficiency
Fault tolerance: 1 drive bersamaan; Read gain: 3×, Write gain: 1× (Parity write penalty)

Frequently Asked Questions (FAQ)

Why is the hard drive capacity reported by the operating system smaller than the manufacturer label?

Drive manufacturers measure capacity using decimal SI units (1 TB = 10^12 bytes), whereas operating systems like Windows calculate storage in binary IEC units (1 TiB = 2^40 = 1,099,511,627,776 bytes). A physical 1 TB drive displays as approximately 0.91 TiB in system properties.

Why is RAID 5 discouraged for modern large-capacity drives (above 4 TB)?

When a failed drive is replaced, the rebuild process must read every sector across remaining drives over many hours or days. The statistical probability of encountering an Unrecoverable Read Error (URE) during this stressful rebuild is significant, causing complete RAID 5 array failure. RAID 6 or RAID 10 is strongly recommended.

When should I choose RAID 10 over RAID 6?

Choose RAID 10 for high-volume random write workloads (such as OLTP transactional databases and VM hypervisors) where you need fast rebuilds and zero parity calculation penalties. Choose RAID 6 for bulk storage, archiving, or video where cost per usable terabyte is the primary factor.

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References & Notes

Last updated: 2026-11-06Content Status: Draft (Pending Editorial Review)

Note: Results above are mathematical estimates based on standard formulas. Always verify against official vendor documentation and site conditions before production deployment.