Blue Color Code (#0000FF)

Blue is an official CSS named color: #0000FF — rgb(0, 0, 255) — hsl(240, 100%, 50%).

HEX	#0000ff
RGB	rgb(0, 0, 255)
HSL	hsl(240, 100%, 50%)
Complementary	#ffff00 (hue + 180°)
CSS name	blue (official keyword)

color: blue; background-color: #0000ff; border-color: hsl(240, 100%, 50%);

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The color blue in CSS

Blue is one of the 148 named colors defined by the CSS Color Module — write the keyword blue anywhere a color value is accepted (color, background-color, border-color, gradients) and every browser renders exactly #0000FF (rgb(0, 0, 255)).

Shades and tints of blue

Same hue and saturation, stepped through lightness — click any swatch for its own page:

Popular color codes

red orange coral salmon tomato gold yellow olive green lime teal aqua turquoise navy #4f7cff #ff6b6b

Convert any color with the HEX, RGB and HSL converter.

Common input mistakes (and fixes)

Modern space-separated CSS fails. Values like rgb(249 115 22) or hsl(25 95% 53%) are rejected — every field here expects commas, so write rgb(249, 115, 22) and hsl(25, 95%, 53%).
Percentages or decimals in RGB fail. Channels must be whole numbers from 0 to 255; rgb(97%, 45%, 8%) and rgb(249.5, 115, 22) both trigger a red error.
Wrappers are optional. Pasting bare 249, 115, 22 into the RGB field, or 25, 95%, 53% into HSL, converts fine — and HEX accepts upper or lower case, with or without the leading #.
Hue wraps around. Entering hsl(360, 100%, 50%) gives the same pure red as hue 0.

Why an HSL round trip can shift by one

This tool rounds HSL values to whole numbers, so converting away and back can drift slightly. Example: #f97316 becomes hsl(25, 95%, 53%), and converting that back gives rgb(249, 116, 21) — one step off on two channels. That is rounding, not a bug: whole-number HSL offers roughly 3.7 million combinations, while RGB has 16,777,216, so some colors simply have no exact HSL match. Treat the 6-digit HEX as the exact value and HSL as a close, editable approximation.

Frequently asked questions

What color is blue?

Blue is an official CSS named color with the hex code #0000FF — rgb(0, 0, 255) in RGB and hsl(240, 100%, 50%) in HSL. Its complementary color (hue + 180°) is #ffff00.

How do I use the blue color in CSS?

Write color: blue; for text or background-color: blue; for surfaces — the keyword works in every browser, no quotes needed. Equivalent notations: #0000FF, rgb(0, 0, 255) and hsl(240, 100%, 50%).

Is blue the same as #0000FF?

Yes — the CSS keyword blue is defined as exactly #0000FF (rgb(0, 0, 255)), so the keyword and the hex code always render the identical color.