CIDR to IP Range

Convert CIDR notation to IP ranges, and IP ranges back to minimal CIDR lists. IPv4 and IPv6.

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First address
Last address
Total addresses
Try:
Total addresses
CIDR blocks

CIDR notation in a nutshell

CIDR (Classless Inter-Domain Routing) notation describes an IP prefix as an address plus the number of fixed leading bits, e.g. 10.0.0.0/8. An arbitrary IP range does not always align to a single CIDR block, which is why converting a range can produce several blocks. This converter uses the same primitives that power Ipregistry's IP data API.

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