Synology Drive Calculator

When setting up a Synology NAS (Network-Attached Storage), one of the biggest challenges is estimating how much usable storage you’ll actually get after configuring your drives in RAID. Different RAID levels, disk sizes, and redundancy requirements can make manual calculations confusing.

Synology RAID Storage Calculator

Note: For RAID 5, usable = (N-1)*size; RAID 6: (N-2)*size; RAID 10: (N/2)*size; RAID 1: size; SHR is similar to RAID 5/6 for identical drives. JBOD: sum of all drives.
Always check with Synology’s official calculator for mixed drives or advanced SHR!

The Synology Drive Calculator is an online tool that estimates:

  • Total raw storage capacity based on the number and size of drives.
  • Usable capacity after RAID configuration.
  • Disk efficiency and redundancy percentage.
  • Best RAID options for balancing performance, safety, and storage space.

It’s especially useful when comparing different RAID setups such as RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, and SHR (Synology Hybrid RAID).

How to Use the Synology Drive Calculator

  1. Enter Number of Drives – Input how many HDDs/SSDs you plan to use.
  2. Enter Drive Size – Specify the capacity of each drive (e.g., 2TB, 4TB, 10TB).
  3. Select RAID Type – Choose from RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, or SHR.
  4. Calculate – Instantly get results for usable storage, redundancy, and efficiency.
  5. Compare – Adjust different RAID options to see which setup works best for your needs.

Storage Calculation Formulas

The actual formula depends on the RAID type:

  1. RAID 0 (Striping):
    Usable Storage = Number of Drives × Drive Size
    (No redundancy, maximum efficiency)
  2. RAID 1 (Mirroring):
    Usable Storage = Drive Size (only one drive’s capacity)
    (Redundancy = 50%)
  3. RAID 5:
    Usable Storage = (Number of Drives – 1) × Drive Size
    (Redundancy uses 1 drive for parity)
  4. RAID 6:
    Usable Storage = (Number of Drives – 2) × Drive Size
    (Redundancy uses 2 drives for parity)
  5. RAID 10 (1+0):
    Usable Storage = (Number of Drives ÷ 2) × Drive Size
    (50% redundancy, higher performance)
  6. SHR (Synology Hybrid RAID):
    Usable Storage = Total Capacity – Largest Drive (for 1-disk redundancy)
    (flexible with different drive sizes)

Example Calculations

Example 1 – RAID 5 Setup

  • 4 drives × 4TB each
  • Formula: (4 – 1) × 4TB = 12TB usable storage

Example 2 – RAID 6 Setup

  • 6 drives × 6TB each
  • Formula: (6 – 2) × 6TB = 24TB usable storage

Example 3 – RAID 10 Setup

  • 8 drives × 2TB each
  • Formula: (8 ÷ 2) × 2TB = 8TB usable storage

Example 4 – SHR Setup (Mixed Drives)

  • 2 × 6TB + 2 × 4TB
  • Usable = 6TB + 4TB + 4TB – 6TB = 8TB usable storage

Benefits of Using a Synology Drive Calculator

  • Accuracy: No guesswork in RAID calculations.
  • Planning: Helps decide how many drives to buy.
  • Efficiency Check: See storage loss due to redundancy.
  • Flexibility: Compare different RAID setups instantly.
  • Cost Optimization: Prevents overbuying or underutilizing drives.

Real-Life Applications

  • Home Media Server: Plan storage for movies, photos, and backups.
  • Small Businesses: Balance data protection with usable storage.
  • Enterprises: Ensure redundancy without compromising performance.
  • Hybrid Drive Setups: Calculate SHR capacity when using different drive sizes.

20 Frequently Asked Questions (FAQs)

1. What is the Synology Drive Calculator?
It’s a tool to calculate NAS storage capacity based on drives and RAID setup.

2. Why do I need it?
Because RAID configurations change the amount of usable storage.

3. Does RAID affect storage capacity?
Yes, redundancy uses part of the total drive space.

4. What is RAID 0 best for?
High speed, but no redundancy.

5. What is RAID 1 best for?
Data protection, since one drive mirrors the other.

6. Is RAID 5 safe?
Yes, but only one drive can fail without losing data.

7. How safe is RAID 6?
Safer than RAID 5, as two drives can fail.

8. What is RAID 10?
A mix of RAID 1 and RAID 0, balancing speed and redundancy.

9. What is SHR in Synology?
Synology Hybrid RAID, which allows flexible drive sizes.

10. Can I mix different drive sizes in SHR?
Yes, unlike traditional RAID setups.

11. How do I calculate RAID efficiency?
Efficiency = (Usable Storage ÷ Raw Storage) × 100%.

12. Is the calculator accurate?
Yes, it follows standard RAID formulas.

13. Can I upgrade drives later?
Yes, Synology NAS supports drive replacement and expansion.

14. Which RAID is best for home use?
RAID 5 or SHR are popular choices.

15. Which RAID is best for business use?
RAID 6 or RAID 10 for better protection and performance.

16. What happens if a drive fails in RAID 0?
All data is lost.

17. Can I calculate SSD storage too?
Yes, the calculator works for both HDDs and SSDs.

18. Does Synology NAS waste storage?
Not wasted, but part is reserved for redundancy and protection.

19. Can I use the calculator before buying drives?
Yes, it helps plan purchases and avoid overspending.

20. Is the Synology Drive Calculator free?
Yes, it’s a free tool available online.

Final Thoughts

The Synology Drive Calculator is the perfect companion for anyone setting up or upgrading a Synology NAS. By accurately showing usable storage, redundancy, and efficiency, it saves time, money, and confusion.

Whether you’re a tech enthusiast building a home server or a business ensuring reliable backups, this calculator makes NAS planning simple and precise.