IP Range to CIDR Calculator
IP Range to CIDR Calculator: Computes continuous binary powers of two to generate the minimal set of enclosing CIDR blocks.
About this ip range to cidr calculator
IP Range to CIDR Calculator — browser-based utility.
How this tool works
Implements client-side IP Range to CIDR Calculator operations. Computes continuous binary powers of two to generate the minimal set of enclosing CIDR blocks specifically designed for a firewall administrator converts an arbitrary starting and ending ip range into optimal cidr blocks.
- Binary Bitmask Ingestion: Converts decimal dotted-quad IPv4 strings or hexadecimal colon-separated IPv6 strings into binary bit vectors.
- Bitwise Boolean Algebra: Performs bitwise AND, OR, and NOT operations between IP address integers and CIDR prefix masks.
- Address Class & Scope Tagging: Identifies RFC 1918 private ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16), loopback, CGNAT, and multicast blocks.
- Subnet Topology Formatting: Renders network ID, usable host range, broadcast address, binary representation, and Cisco wildcard mask.
Worked example
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:
Limits and verification
Enforces strict IPv4 prefix boundaries (/0 to /32) and IPv6 boundaries (/0 to /128). In RFC 3021 /31 subnets, correctly reports 2 usable point-to-point hosts without traditional network and broadcast exclusions.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
- RFC 791 (Internet Protocol: IPv4)
- RFC 4632 (Classless Inter-domain Routing: CIDR)
- RFC 4291 (IP Version 6 Addressing Architecture)
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the IP Range to CIDR Calculator workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
How does IP Range to CIDR split a range?+
It parses two IPv4 endpoints and repeatedly chooses the largest aligned power-of-two block that does not pass the end address.
What did the browser vector verify?+
The inclusive range 192.0.2.0-192.0.2.15 returned the single minimal block 192.0.2.0/28.
Are endpoints included in the result?+
Yes. The first block begins at the supplied start and the iterative blocks cover through the supplied end without gaps.
What input order is required?+
Input must contain two valid IPv4 addresses separated by a hyphen or space, and the end must not precede the start.