IPv6 Expander

Enter a compressed IPv6 address and get the full 8-group notation with groups, binary, and bit count.

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Input
Output
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About ipv6 expander

IPv6 Expander is one page doing one thing. No account, no settings to sync, no history building up somewhere.

There is no account and no upload step. Whatever you paste lives in a variable until you close the tab, and then it does not.

You will find it under Network, alongside 17 other tools for the same sort of job.

Supports multiple addresses separated by newlines.

How to use it

01
Start it
Every control is on the tool itself. Keyboard shortcuts, where there are any, are listed beside it.
02
Watch it run
It updates in the page as you go. Nothing is sent anywhere, so it keeps working with the network off.
03
Close when done
Nothing is stored between visits. Reloading gives you a clean start rather than picking up where you left off.

Examples

Expand 2001:db8::1 to full notation
Expand a compressed IPv6 address to all 8 groups with binary representation
Input
2001:db8::1
Output
Input: 2001:db8::1
Expanded: 2001:0db8:0000:0000:0000:0000:0000:0001
Groups: 2001, 0db8, 0000, 0000, 0000, 0000, 0000, 0001
Binary: 0010000000000001:0000110110111000:0000000000000000:0000000000000000:0000000000000000:0000000000000000:0000000000000000:0000000000000001
Total bits: 128

Questions

Does IPv6 Expander work offline?+

Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.

Does it remember anything between visits?+

No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.

Is it accurate?+

Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.

Does it make a sound?+

Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.

Can I use IPv6 Expander on a phone?+

Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.