/21 Subnet Mask: 255.255.248.0

Answer
255.255.248.0 · 2,046 usable hosts

A /21 network uses 21 bits for the network and 11 for hosts, giving 2,048 addresses and 2,046 usable hosts. It is typically used for large office networks.

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    /21 at a glance

    PropertyValue
    Subnet mask255.255.248.0
    Wildcard mask0.0.7.255
    Total addresses2,048
    Usable hosts2,046
    Size relative to /248 × /24

    Example: 192.168.0.0/21

    FieldAddress
    Network192.168.0.0
    First host192.168.0.1
    Last host192.168.7.254
    Broadcast192.168.7.255

    Frequently asked questions

    How many hosts are in a /21?

    2,046 usable hosts out of 2,048 addresses.

    What is the wildcard mask for /21?

    0.0.7.255, the inverse of 255.255.248.0.

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