IP Range to Minimal CIDR Aggregator
CIDR AggregatorConvert arbitrary start and end IP address ranges into the minimal set of CIDR prefix blocks directly in your browser. Optimize firewall rule tables, simplify cloud security groups, and summarize routing prefixes with 100% in-browser bitwise aggregation.
IP Range to Minimal CIDR Aggregator
Convert arbitrary starting and ending IP addresses into the minimal set of valid CIDR blocks.
Interactive IP Range to Minimal CIDR Aggregator Workspace
Aggregate starting and ending IPv4 address ranges into the smallest possible set of valid CIDR subnet blocks using greedy binary power-of-two aggregation algorithms in your browser.
How This Tool Works (100% Client-Side Engine)
The tool converts start and end IPs into 32-bit unsigned integers. Starting at the lowest IP, it finds the largest CIDR block that fits within the range and aligns with the current IP binary boundary: maxBlockSize = startIP & (-startIP). It advances the current pointer by the block size until the end IP is reached.
Step-by-Step Guide
Enter Start & End IP Addresses
Type your beginning IP (e.g. 192.168.1.10) and ending IP (e.g. 192.168.1.150).
Compute Minimal CIDR Blocks
The tool calculates the optimal set of CIDR prefixes that covers the range exactly.
Copy CIDR List
Copy the consolidated list of CIDR blocks directly to your clipboard for your firewall or router configuration.
Why Use This Tool: Privacy & Performance
Network security teams and cloud administrators frequently need to whitelist or block specific IP address ranges (e.g. 192.168.1.50 through 192.168.1.180). However, modern firewalls, cloud security groups (AWS, Azure, GCP), and BGP routing engines do not accept arbitrary start-to-end IP ranges; they require clean Classless Inter-Domain Routing (CIDR) notation. Converting an arbitrary range into CIDR blocks manually requires calculating binary power-of-two boundaries that align with bitwise masks. ToolByte IP Range to CIDR Aggregator automates this calculation using greedy prefix aggregation algorithms. You enter start and end IP addresses, and the tool calculates the exact, minimal list of CIDR blocks that covers the range without under-covering or over-covering, ready to paste into firewall rules with zero tracking.
Common Use Cases & Workflows
Simplifying Cloud Security Group Rules
Convert vendor IP ranges into minimal CIDR blocks to avoid exceeding AWS 60-rule security group limits.
BGP Route Summarization
Aggregate multiple contiguous subnet allocations into minimal supernet route advertisements to shrink routing tables.
Firewall & WAF IP Whitelisting
Translate corporate VPN or partner office IP pools into standard CIDR notation for Cloudflare or Nginx firewall rules.
Log Analysis & GeoIP Range Mapping
Map database IP start/end ranges from GeoIP providers into compact CIDR lookup lists.
Technical Limitations & Operational Boundaries
Frequently Asked Questions
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