All tools · 🌐 Network Tools
🧩 CIDR Aggregator
Firewall rule lists accumulate over time and end up with overlapping or adjacent CIDR blocks. This tool aggregates them into the smallest equivalent set — duplicates removed, adjacent blocks merged, contained blocks dropped.
Loading tool…
Examples
Adjacent blocks
Input
10.0.0.0/25, 10.0.0.128/25Output
10.0.0.0/24 (merged)Frequently asked questions
When is this useful?
Cleaning up firewall rules, BGP route announcements, or any list of IP allowlists. Smaller rule sets are faster to match and easier to audit.
About this calculator
CIDR Aggregator runs entirely in your browser using standard formulas. No data is sent to any server. We don't share your inputs with lenders, brokers, or anyone else — there's no funnel and no follow-up email.
Related tools
- 🧮 Subnet / CIDR Calculator — Calculate network, broadcast, host range, mask from any CIDR notation.
- 🔁 IP Range to CIDR — Convert an IP range (10.0.0.1 - 10.0.0.255) to the minimum set of CIDR blocks.
Why this tool
vs typical free network-tools sites
| NetToolset | Typical free site | |
|---|---|---|
| Price | Free | Free |
| Signup required | No | Often (for advanced features) |
| Ads inside the tool | No | Yes (banner + interstitial) |
| Logs your IP / queries | No | Yes (often resold) |
| Data sent to a server | Math runs in browser; lookups hit Cloudflare DoH directly | Yes (all goes through their server) |
| Open source | Yes | No |
| Bookmarkable URL per tool | Yes | Mixed |
| Multilingual | EN / ES / PT / FR / DE | Usually EN only |
| Loads in under 1s | Yes (static) | Often slow (ad tracking) |