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RAID Calculator

1 Click on an HDD

Selected Configuration

1 Click on an HDD

  • 2Select the RAID type you wish to be compared, and the result will be available immediately

    RAID Type


    Unused space
    Used for protection
    Available space

    3Select the recommended models and compare them

    Recommended Models

    Other models


    1. Visit here for more information on choosing the correct HDD for your Synology DiskStation.
    2. Synology RAID Calculator offers you an estimate on the space utilization with various mixed HDD configurations and RAID types. Actual HDD sizes can vary between vendors, and values calculated may differ from actual results. Please refer to Synology Storage Manager for precise data calculations for storage installed in your Synology DiskStation.
    3. When using SHR or SHR-2 HDD protection as your RAID type, the Unused space will be automatically reserved for future expansion. On the contrary, Unused space under other RAID types indicates the space that can't be utilized and is thus wasted.
    4. The result of calculation helps you evaluate the available space when you are creating a new volume only. If you're going to expand an existing volume, please read Expand Volumes or Disk Groups by Adding Hard Disks and Expand Volumes or Disk Groups by Replacing Hard Disks for detailed information.
    5. Models listed under "Other models" support the selected number of drives and their capacities but may have limitations on how large you can create a single volume. In cases where you are over the limit, you may create multiple volumes or designate a drive as a hot spare. Some models can support larger single volume capacities after upgrading the installed memory capacity. To find out more, please refer to Why does my Synology NAS have a single volume size limitation of 16, 108, or 200 TB?
    6. The Synology RAID Calculator makes recommendations based on the total capacity picked. Some models or configurations may not support a certain capacity drive but will be able to achieve the total capacity through other combinations or when paired with an expansion unit. Always check and refer to the HDD/SSD compatibility list for the latest information.
    7. Results from the RAID Calculator should be used as a reference only. The decimal prefix is used to show the calculated result of disk-array capacity. However, since Synology DSM calculates the volume size based on binary prefix, this tool does not reflect the conversion deviation. Check with a certified Synology sales or support representative for confirmation. Synology makes no guarantees for results generated with this tool.