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IPv6 Subnet Calculator

Network: 2001:db8::

First Address: 2001:db8::

Last Address: 2001:db8::ffff:ffff:ffff:ffff

Prefix: /64

Addresses: 18,446,744,073,709,551,616

About This Tool

The IPv6 Subnet Calculator is a powerful tool designed to help network administrators, developers, and IT professionals calculate and analyze IPv6 subnets. With the exponential growth of Internet-connected devices, IPv6 has become essential for modern networking infrastructure. This calculator simplifies the complex task of IPv6 subnet planning and management.

How to Use

  1. Enter a valid IPv6 address in the IPv6 Address field (e.g., 2001:db8::1)
  2. Specify the prefix length (0-128) in the Prefix field
  3. The calculator will automatically display the network address, first address, last address, and total number of addresses in the subnet

Features

  • Real-time calculation as you type
  • Support for all valid IPv6 address formats (compressed and uncompressed)
  • Prefix length validation (0-128)
  • Formatted output with thousands separators for easy reading
  • Display of network boundaries and address count
  • Clean, user-friendly interface

Common Use Cases

  • Planning IPv6 network allocations for organizations
  • Calculating subnet sizes for different departments or VLANs
  • Verifying IPv6 address assignments
  • Learning and understanding IPv6 subnetting concepts
  • Troubleshooting IPv6 network connectivity issues
  • Documenting network infrastructure

Technical Details

IPv6 uses 128-bit addresses, providing approximately 3.4×1038 unique addresses. Unlike IPv4, IPv6 subnetting is typically done on nibble (4-bit) boundaries for easier management.

Common IPv6 prefix lengths:

  • /48 - Typical site allocation
  • /56 - Small site or home network
  • /64 - Single subnet (standard for end networks)
  • /128 - Single host address

The calculator handles both expanded and compressed IPv6 notation, making it easy to work with addresses in any format.