Tool overview
What is a Subnet Calculator?
A subnet calculator computes CIDR ranges, masks, network/broadcast addresses, and usable host counts from IP inputs.
Why use this Subnet Calculator?
Plan VPC and LAN allocations quickly without spreadsheet math or leaking network diagrams to a third party.
Key Features
CIDR math, broadcast/host counts, instant results, and private client-side calculation.
How to Use
Follow these steps to get accurate results from the tool interface above.
- Enter CIDR notation (192.168.1.0/24) or IP + mask.
- Read network, broadcast, first/last host, and usable host count.
- Use results for firewall rules, VPC planning, or interview prep.
CIDR Planning Specs
CIDR notation
Prefix length determines host bits—/24 yields 256 addresses, 254 usable hosts.
RFC1918 ranges
10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 are private-use.
Broadcast address
Last address in subnet—typically excluded from assignable host pools.
Frequently Asked Questions
Expandable answers for common debugging bottlenecks and data privacy questions.
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Official Documentation & References
Authoritative specifications and platform documentation for this utility.