How to Use the CIDR Subnet & IP Range Calculator
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1
Enter an IPv4 address with CIDR prefix (e.g. 10.0.0.0/8).
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2
View subnet mask, network address, broadcast address, first/last usable host, and total hosts.
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3
See the full IP range in dotted decimal format.
Practical Example & Use Case
Common Real-World Scenario
Planning a /27 subnet (192.168.1.96/27) to get exactly 30 usable host addresses for a small office.
Technical Notes & Limitations
Browser Engine Architecture
IPv4 only. CIDR prefixes /0 through /32 are all supported.
Frequently Asked Questions
What is CIDR notation?
CIDR uses a suffix like /24 to specify how many bits are the network portion, leaving the rest for hosts.
How many usable hosts does /24 give?
/24 has 256 total addresses but only 254 usable hosts — network and broadcast addresses are reserved.