What is IP to CIDR Aggregation (Supernetting)?
IP to CIDR Aggregation (also known as Route Summarization or Supernetting) is a process that combines multiple contiguous or adjacent IP addresses into a single larger CIDR prefix (e.g. combining 192.168.1.0 through 192.168.1.3 into 192.168.1.0/30).
Cloud providers and hardware firewalls impose strict quotas on the number of security group rules (e.g. AWS 60 rules per Security Group). Aggregation shrinks rule sets while preserving exact network coverage.
How to aggregate IP addresses into CIDR blocks
- Paste your IP address list. Paste raw IPv4 addresses, mixed subnets, or IP ranges into the text area above.
- Click Aggregate into CIDRs. The tool sorts, merges contiguous and overlapping intervals, and applies optimal bitwise prefix collapsing.
- Review the optimized CIDR list. See the compressed list of CIDR blocks alongside the rule reduction percentage.
- Export for firewall configuration. Copy the aggregated list or download as TXT/CSV to paste directly into AWS, Azure, Cloudflare, or pfSense.
What is generated by the aggregator?
- Minimal CIDR Prefix Set — The smallest possible mathematical combination of subnet blocks.
- Overlap Elimination — Duplicate IP addresses and nested subnets automatically merged into parent ranges.
- Compression Metrics — Original entry count vs aggregated CIDR count and percentage reduction.
- Standard Text & CSV Formats — One CIDR block per line ready for automated CLI ingestion.
Supported input formats
Accepts individual IPv4 addresses (1.1.1.1), CIDR notation (10.0.0.0/24), and mixed delimiter lists (newlines, spaces, commas, semicolons).
Privacy and security
Processing happens entirely inside your browser tab using bitwise arithmetic. Internal corporate IP addresses, customer allowlists, and sensitive VPC topologies are never sent across the internet.
Known limitations
Currently processes IPv4 address aggregation. IPv6 aggregation is planned for a future update.
Common use cases
- Cloud Firewall Optimization — Compressing 500 office IPs into 10 CIDR blocks to fit under AWS/GCP security group limits.
- WAF & CDN Allowlists — Managing IP access rules in Cloudflare, Fastly, and Akamai.
- Routing Table Summarization — Cleaning up internal BGP and OSPF route tables.
IP to CIDR Aggregator vs CIDR Extractor
Use the IP to CIDR Aggregator to condense multiple IPs into CIDR blocks. If you want to calculate network boundaries or expand a single CIDR block into a list of usable IPs, use our CIDR & subnet extractor.
Frequently asked questions
How does CIDR aggregation reduce firewall rules?
It merges adjacent IP addresses that share a common binary prefix into a single CIDR mask, dramatically reducing rule count without changing access permissions.
Can I paste both single IPs and existing CIDRs together?
Yes. The aggregator parses mixed inputs, resolves overlaps, and outputs a clean minimal CIDR list.
How does it handle duplicate IP entries?
Duplicates are automatically deduplicated during binary interval sorting.
Is there a limit on how many IP addresses I can paste?
The in-browser engine comfortably aggregates lists of over 50,000 IP addresses in a few seconds.
Are my private IP addresses sent to any server?
No. All bitwise calculations run locally in your browser memory via JavaScript.