IP Range to CIDR Calculator
Converts an inclusive IPv4 start–end range into the smallest exact set of aligned CIDR blocks, without filling gaps outside the range.
About this ip range to cidr calculator
Converts an inclusive IPv4 start–end range into the smallest exact set of aligned CIDR blocks, without filling gaps outside the range Performs protocol inspection, IP calculation, and network analysis client-side without sending probes or exposing network topology.
Protocol mechanics & network logic
Converts one inclusive IPv4 start–end range into the smallest sequence of aligned CIDR blocks that covers every address and no address outside the range.
Worked network diagnostic scenario
Scenario: Cover a short inclusive IPv4 interval with aligned CIDR blocks.
Sample input:
Processing: Start at the lower endpoint and select the largest aligned power-of-two block that remains within the upper endpoint.
Illustrative output:
Addressing limits & protocol boundaries
Input must be two canonical dotted IPv4 addresses separated by one hyphen, with start less than or equal to end. Prefixes, extra text, empty octets, non-decimal notation, and an end before start are rejected. The result is local arithmetic only: it does not query routes, allocations, firewalls, or address reachability.
Addressing calculations and subnet models in IP Range to CIDR Calculator follow IETF RFC definitions. Ensure subnet masks and CIDR prefixes match your network topology.
Offline network inspection boundary
Address parsing and CIDR calculations in IP Range to CIDR Calculator run entirely client-side without probing external IP networks or transmitting routing data.
IETF RFC specifications & IANA registries
IETF Request for Comments (RFC) standards and IANA registry references:
- RFC 791 (Internet Protocol: IPv4)
- RFC 4632 (Classless Inter-domain Routing: CIDR)
- RFC 4291 (IP Version 6 Addressing Architecture)
IP Range to CIDR Calculator verification · Audit standards
How to use it
- Enter 192.0.2.0-192.0.2.15 with one hyphen between start and end.
- Click Run locally; the tool validates both endpoints and chooses each largest aligned block without crossing the end.
- Read blocks, the minimal exact CIDR cover; it is not one supernet that fills gaps.
Frequently asked questions
How does IP Range to CIDR split a range?+
It repeatedly chooses the largest aligned power-of-two CIDR block that starts at the remaining lower address and does not pass the upper address.
Can I try an example range?+
Enter `192.0.2.0-192.0.2.15` with one hyphen and choose Run locally. The exact minimal result is `192.0.2.0/28`.
Are both endpoints included?+
Yes. The blocks cover every address from the supplied start through the supplied end without filling addresses outside that inclusive range.
What input is accepted?+
Enter two canonical dotted-decimal IPv4 addresses separated by exactly one hyphen, with the end no earlier than the start. Prefixes, extra text, empty octets, non-decimal forms, and reversed ranges are rejected.