Hex Color Validator

Check if a hex color code is valid.

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Input
Output
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About hex color validator

Hex Color Validator does its work in front of you rather than sending anything away to be processed. What you see is the whole of it.

The page holds your input in memory and nowhere else. No cookie stores it, no request sends it, and a reload wipes it.

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

Supports 3-digit, 4-digit (with alpha), 6-digit, and 8-digit (with alpha) hex formats, the # prefix is required.

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

Valid 6-Digit Hex
Validate a standard 6-digit hex color code
Input
#FF5733
Output
Valid hex color (6-digit): #FF5733
Invalid Hex Color
Detect a hex color with invalid characters
Input
#GGHHII
Output
Invalid hex color: Invalid hex digits or length (expected 3, 4, 6, or 8 hex digits after #)

Questions

Does Hex Color Validator 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 Hex Color Validator 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.