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RAID Calculator

Estimate usable capacity, space used for protection, and unused capacity for common RAID levels. Results update instantly as you change inputs.

Real-time Mixed drive sizes Mobile-friendly

Array setup

If mixed sizes are used, parity-based RAID levels are limited by the smallest drive size per group.
How this estimate works: We calculate total raw capacity, then subtract parity/mirror overhead and show any unusable remainder created by mixing drive sizes.

Results

Usable capacity
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Protection / parity
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Unused (from mixed sizes)
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Usable Protection Unused
Note: This is an estimate. Actual usable capacity can differ due to OS formatting, system partitions, vendor TB vs OS TiB reporting, and device/model limits. Use results as a planning reference, then confirm in your NAS/RAID manager.

RAID Calculator Overview

How the RAID Calculator Works in Real Use

When I first started working with storage systems, I realized how confusing RAID planning could be. That is why using a RAID calculator makes things much easier. The calculator is designed to keep the inputs simple and straightforward, even for someone who is not deeply technical. You only need to select the RAID type, enter the drive capacity, define the cost, choose the drives per RAID, and set the number of RAID groups.

This tool supports over 10 major types of RAID setups, which helps both beginners and professionals compare options quickly. The data units are fully supported, and every input is easy to understand. Even though the default pricing uses U.S. dollars, any currency can be entered, and the output will stay consistent because the RAID calculator software does not perform currency conversions.

From my experience managing storage for both home labs and office environments, this flexibility is extremely helpful. Whether you are planning a small NAS or a large enterprise array, understanding RAID capacity is critical. The calculator generates multiple outputs, including advanced metrics such as redundancy factor, price per usable TB or GB, and performance-related values.

One feature I personally rely on is how clearly it shows read speed and write speed gains. These numbers make it easier to judge whether a specific configuration is worth using for your selected particular case, whether that is a server or a workstation. The clarity of this decision-making process saves time and prevents costly mistakes.

From a planning standpoint, the calculator gives deep insight into storage, overall performance, and accurate calculation of resources before the actual setup. It also supports side-by-side evaluation and comparison, which is useful when choosing between different RAID layouts.

“This calculator is part of our Everyday Life & Tools calculators collection, which covers conversions, sports metrics, gaming calculations, and travel planning.”

For technical accuracy and industry standards, RAID behavior and performance models align with documentation available from trusted sources such as:
 https://en.wikipedia.org/wiki/RAID

RAID Basics Explained

When I first started working with storage systems, understanding RAID became much easier after using a RAID calculator. RAID means Redundant Array of Independent Disks, also known as Redundant Array of Inexpensive Disks. It is a data storage virtualization technology that combines multiple physical disk drive components into logical units.

The main purposes of RAID are data redundancy, performance improvement, or sometimes both. The term was coined in a research paper by Patterson in 1987 and 1988, where it was shown that an array of magnetic disks could outperform expensive mainframe drives. This proved the business case and confirmed that the need for RAID calculator solutions truly exists.

In RAID systems, data is distributed across multiple drives, whether HDD or SSD, using different ways called RAID levels. Each configuration depends on the required performance, redundancy, and the right balance between key variables such as reliability, availability, and capacity.

Several techniques make RAID work efficiently. Mirroring ensures identical data is copied to more than one drive. Striping divides storage space into smaller units, sometimes down to a sector or a few mb, improving speed. Parity stores information that is striped across disks so the system can continue working even during a drive failure. This recovery depends on the XOR operation, allowing data to be restored after a failure.

A RAID calculator visually explains these ideas using graphs, a levels table, and helpful visuals. While RAID 0 focuses on speed, higher RAID levels provide protection from unrecoverable sector read errors, system failures, and even complete loss of whole physical drives. A detailed list of supported RAID levels is normally included in the tool, making it easier to compare options and plan storage accurately.

Reference:
https://en.wikipedia.org/wiki/RAID

RAID Levels Explained

When working with a RAID calculator, understanding different RAID levels and their configurations is very important for calculating correct RAID capacity. From my own experience setting up storage systems, I’ve learned that choosing the right setup saves both time and money while improving reliability.

The most basic option is RAID 0, which uses striping only. This is the simplest configuration because it works without mirroring or parity. There is no redundancy or recovery, but it offers high performance. Both reads and writes improve because data is split across drives, and speed approaches the sum of the throughputs of every drive in the set. The big benefit of this spanned layout is speed, not safety.

With RAID 1, mirroring is used. The data is written identically to two drives in a mirrored set. Any read request can be serviced from either disk, achieving redundancy. A hypothetical speed increase is possible for reads, but write speed is negatively affected because the slowest drive limits the array.

RAID 1E combines striping with mirroring, where each written stripe is mirrored to remaining disks. It offers better random read performance even in a degraded array. This enhanced version is still preferred in some cases, and the calculator supports it.

RAID 2 uses bit-level striping with dedicated parity, but it is rarely used and not supported by most tools. RAID 3, based on byte-level striping, has similar limitations.

RAID 4 uses block-level striping and offers an advantage over RAID 2 and 3 because of improved I/O parallelism. A single request does not require reading the whole group, which improves small transfers.

RAID 5 introduces distributed parity. Unlike RAID 4, parity is spread across disks, allowing the system to operate even if one drive fails. However, it can be susceptible to system failures during long rebuild time, especially if a second drive fail occurs. Because of this usage, it may not always be ideal.

RAID 5E / 5EE adds an integrated hot spare that stays active in rotation, spreading the load and giving increased performance. The spare cannot be shared, but it is considered enhanced in reliability.

RAID 6 uses double parity, providing fault tolerance for two failed drives. It works well for larger arrays and high-availability systems. Although rebuilds can be big and slow, once restored, the calculation clearly shines in enterprise use.

RAID 10 combines mirroring without losing block-level speed. It consists of a striped series of RAID 1 over RAID 0, allowing the array to survive failures while maintaining high security.

RAID 50 combines multiple RAID 5 groups, allowing the system to tolerate drive loss with improved writes. Using hot spares further strengthens reliability.

RAID 60 requires a minimum number of disks and offers strong reliability, but at a heavy cost to usable capacity. A large percent of overall disk space is lost. When exploring options, you may notice you lose between 12% and 50%, due to parity information being added. Still, reads are boosted, making it suitable for demanding workloads.

For deeper technical reference, RAID behavior and design are documented here:
 https://en.wikipedia.org/wiki/RAID

RAID Calculator Guide

 Choosing the Right RAID Level

When using a RAID calculator, the first question most people ask is which RAID level they should choose. The right answer always depends on the application you are working on. In my experience managing storage systems, I’ve learned that performance is often the most important factor at the start, but it should never be the only one.

If speed is your top priority, RAID 0 is often the first choice. You can start with just two disks, making it the cheapest option available. However, you should expect to lose all data if a drive fails, because there is no fault tolerance. It is fast, but risky.

If you need better protection and quicker rebuild times, then RAID 10 becomes a strong option. It offers better capacity utilization, although it is limited to 50%. Every RAID option has its pros and cons, which is why it’s always best to try different possible configurations using a calculator. This helps show how each setup will use storage and how performance depends on design choices.

Some setups are good and cheap, but they come with higher data loss risk. Others focus on speed, while some aim for reliability during failure scenarios. Choosing the right storage design is a decision based on comparison, real-world example, and expected usage. Your final setup should balance efficiency, reliability, reading, and writing performance.

H3: Worked Example of RAID 6 vs RAID 10

A RAID 6 array usually consists of 5 disks, each with 1 TB size. It uses parity blocks across each data stripe, meaning two disks are used for parity. This leaves usable capacity of 3 TB, with the rest unavailable.

To calculate utilization, we use a simple formula:

total capacity = 5 TB
 usable capacity = 3 TB
 utilization = 60%

This percentage shows how space is allocated. The read speed factor depends on the maximum theoretical throughput. The read speed gain follows this equation:

  1. disks – 2

In this case, 5 – 2 = 3, which defines the performance level. The fault tolerance allows the system to fail without loss of data as long as no more than two drives fail.

Now consider cost calculations. If each disk costs 50 dollars, the total cost is 250. The cost per usable TB is divided as:

250 / 3 = 83.33

With RAID 10, the standard option requires the same amount of storage, but an even number of disks. The minimum is 6 disks. Write speed is handled by half the drives, which gives better increase compared to RAID 6.

Although nominally the same, RAID 10 can lose one drive per half of the array. If you are unlucky and a second failure occurs, data loss can happen. That makes it not quite as good as RAID 6 in terms of protection, though it is often cheaper and slower for writing, but faster for reading.

Different applications place different demands on storage. What really helps you determine the best option is understanding how vital read and write performance is for your workload. A proper comparison, including RAID 5, checking minimum drives, and running values through a calculator, will always give the clearest answer.

Reference for technical accuracy:
 https://en.wikipedia.org/wiki/RAID

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Disclaimer Notice
Before making any financial decisions or taking any action, you must consult with a qualified and licensed financial advisor, accountant, or other professional who can provide advice tailored to your individual circumstances.