What does the eight-digit hex mean?

The last two digits are alpha — 00 is fully transparent, FF fully opaque. #3B82F680 is the same blue at roughly 50%.

Why does my colour look different in another application?

Colour profiles. A value is an instruction to a display, and the same instruction produces different light on different screens. Design tools that manage colour profiles and browsers that mostly do not will disagree on a wide-gamut display.

Should I use HSL or OKLCH in CSS?

OKLCH if you are generating a palette programmatically, because its lightness behaves predictably. HSL is fine for one-off values and is understood everywhere.

Is there a difference between #FFF and #FFFFFF?

No. The short form expands each digit — #ABC is #AABBCC. It only works when all three pairs happen to be doubled digits.

Color Converter

Converts a colour between HEX, RGB, HSL and the modern CSS colour functions, showing every form at once alongside a preview.

Runs in your browser — nothing is uploaded

Colour

Hex

Formats

HEX: #2A78D6
RGB: 42, 120, 214
HSL: 213, 68%, 50%

On white

4.42:1

Large text only

On black

4.76:1

Passes AA for body text

Need this as an API?

Why use it

Built to be genuinely useful

Every format at once

Change one and the rest follow, so there is no converting twice to get from a design tool's HSL to the hex a stylesheet wants.

Alpha is carried through

Transparency survives the conversion, in the eight-digit hex and the slash notation both, rather than being quietly dropped.

Nothing is uploaded

It runs in your browser. Tokens, keys and customer data routinely end up in these tools, and none of it should have to cross a network to be decoded.

Free, no sign-up

No account, no daily cap, and no feature held back behind a paywall.

How it works

Three steps

1
Enter a colour in any supported format.
2
Read the equivalents.
3
Copy the one your code needs.

Why HSL is easier to reason about than hex

Hex describes how much red, green and blue a screen should emit. That is what the hardware needs and almost never what a designer is thinking. Making #3B82F6 slightly darker means adjusting three numbers in a way that is not obvious, and getting it wrong shifts the hue.

HSL splits the same colour into hue, saturation and lightness, which map onto how people actually describe colour: the same blue, a bit less saturated, a bit darker. Building a palette from one hue at several lightnesses is arithmetic in HSL and guesswork in hex.

The newer colour spaces, and when they matter

HSL has a known flaw: equal lightness values do not look equally light. Yellow at 50% lightness appears far brighter than blue at 50%, so a palette built by holding lightness constant comes out uneven.

OKLCH was designed to fix that. Its lightness matches what the eye perceives, so a set of colours at the same L genuinely look equally bright, and it can express colours outside the sRGB range on displays that support them. Browser support is now broad enough to use it directly, with a hex fallback for older browsers.

FAQ

Questions people ask

API access

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