How to Use the IPv4 Subnet & CIDR Calculator
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1
Enter an IPv4 address and choose a CIDR prefix (e.g. 10.0.0.1/16 or 192.168.1.100/24).
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2
The calculator computes Network Address, Usable Host Range, Broadcast Address, and Subnet Mask.
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3
Inspect total and usable host capacities.
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4
Review the 32-bit binary representation showing network bits vs host bits.
Practical Example & Use Case
Common Real-World Scenario
Calculating usable IP range (172.16.0.1 to 172.16.3.254) for an office VPC subnet with prefix /22 (1,022 usable hosts).
Technical Notes & Limitations
Browser Engine Architecture
Calculates standard IPv4 RFC 791 and RFC 4632 CIDR allocations.
Frequently Asked Questions
Why are there 2 fewer usable hosts than total hosts?
The first address in a subnet is reserved for the Network ID, and the last address is reserved for the Subnet Broadcast.