Free tool · Routing & Aggregation
IP Range ⇄ CIDR
An IP range to the minimal CIDR blocks, and CIDR back to a range.
IP range → CIDR blocks
10.0.0.5/32
10.0.0.6/31
10.0.0.8/29
10.0.0.16/30
10.0.0.20/32
16 addresses → 5 CIDR blocks
CIDR → IP range
About this tool
Free IP range to CIDR converter. Turn an arbitrary start–end IP range into the smallest set of CIDR blocks that cover it exactly, and convert any CIDR back to its first/last address and size — built for firewall rules, ACLs and cloud security groups. Everything runs entirely in your browser — nothing you type is sent to a server.
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