NetOpsT

CIDR Reference

Compare common CIDR prefixes, subnet masks and usable host capacity.

Runs locally

Common IPv4 prefixes and their usable host capacity.

PrefixSubnet maskUsable hosts
/8255.0.0.016,777,214
/16255.255.0.065,534
/20255.255.240.04,094
/22255.255.252.01,022
/23255.255.254.0510
/24255.255.255.0254
/25255.255.255.128126
/26255.255.255.19262
/27255.255.255.22430
/28255.255.255.24014
/29255.255.255.2486
/30255.255.255.2522
/31255.255.255.2542
/32255.255.255.2551

Networking TOOL

CIDR Reference

Compare common CIDR prefixes, subnet masks and usable host capacity.

When to use this tool

Use the reference when selecting the right subnet size for a service.

Use it in three steps

  1. Choose a prefix and compare its mask, capacity and common use.
  2. Review the calculated values against your environment and its requirements.
  3. Copy or document the result only after validating it for production use.

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