Plan and validate IPv6 addressing in seconds. Expand/compress addresses following RFC 5952, compute network and range, generate subnets, and run quick validations.

What you can do here

• Convert IPv6 (compressed ⇄ expanded), binary, and 128-bit integer
• View the block’s prefix, network address, and range
• Validate whether an address belongs to the current block
• Subnet a prefix (e.g., /48 → /64) with pagination
• Generate random addresses from the block
• Export subnets to TXT, CSV, or JSON

Tip: we accept abbreviated and full IPv6, as well as IPv4-mapped addresses (e.g., ::ffff:192.0.2.128).

Frequently Asked Questions

What is a valid IPv6 address?

An IPv6 address has 128 bits represented by 8 hextets (0–ffff). The calculator accepts both the abbreviated form with :: and the full form, following RFC 5952.

“Separate Prefix” or “/n” in the address — which takes priority?

If the /n is included directly with the address (e.g., 2001:db8::1/64), it takes priority over the “Separate Prefix” field.

What’s the difference between “Input Prefix” and “Network Address”?

The prefix is the block (e.g., 2001:db8::/48). The network address is the first address of that block with all host bits set to zero (e.g., 2001:db8:: for /48).

What is IPv4-mapped?

It’s a special IPv6 format that embeds an IPv4 address in the form ::ffff:<IPv4>. Example: ::ffff:192.0.2.128. It’s often used so IPv6 applications can accept IPv4 connections without major changes.

How does “within block” validation work?

The tool checks whether the provided address is between the start and end of the calculated range for the current prefix.

How to generate subnets?

Enter the subprefix (e.g., 64). The calculator splits the base block and shows 10 subnets per page, with automatic pagination if there are more.

Can I export the subnets?

Yes. In TXT, CSV, and JSON formats. The export includes all generated subnets, not just the ones visible on the current page.

Does the CSV use commas or semicolons?

By default, commas. For compatibility with some Excel configurations (e.g., in PT-BR), it can be switched to semicolons.

Is there a limit on the number of subnets?

To prevent browser freezes, it’s recommended to export in batches when working with a very large number (e.g., hundreds of thousands).

Are my data saved?

No. All processing happens locally in your browser; we do not store any entered addresses.