CIDR / サブネット計算機

CIDRブロックを入力して、ネットワークアドレス、ブロードキャスト、使用可能な範囲、サブネットマスクなどのサブネット詳細を計算します。すべての処理はブラウザで行われます。

CIDR Notation

Common Subnets

About CIDR / Subnet Calculator

CIDR (Classless Inter-Domain Routing) notation combines an IP address with a prefix length to define a network. This tool calculates all subnet details from a CIDR block. All processing runs in your browser.

Network Address: The first address in the subnet, identifies the network itself.
Broadcast Address: The last address in the subnet, used for broadcasting to all hosts.
Usable Range: Addresses available for host assignment (excludes network and broadcast).
Subnet Mask: Determines which bits identify the network vs. host portion.