Blue color: #0000ff
The CSS keyword blue is #0000ff, rgb(0, 0, 255) or hsl(240, 100%, 50%). Its codes to copy, 50–950 tint scale, harmonies and contrast on white and black.
Part of design tools.
About Blue
Blue is a vivid dark blue. Its hue sits at 264° in OKLCH and 240° in HSL — the two wheels are spaced differently, which is why the numbers disagree.
The keyword blue is one of the sixteen original HTML 4 colors, the whole palette of CSS 1, so it is understood by every browser and every email client ever shipped.
Blue tint scale, 50 to 950
Eleven steps at fixed perceived lightness, in OKLCH, holding blue’s own hue from end to end. The keyword itself falls closest to step 700 (#002ede), the one outlined; step 500 is #447cff.
Harmonies built on Blue
Hue angles measured in OKLCH, so every accent keeps blue’s perceived lightness. Its complement is #6e5000, closest to the named color saddlebrown.
Complementary
Analogous
Triadic
Split-complementary
Blue on white and on black
White text reads better on blue (8.59:1). As a text color it is readable on a white page (8.59:1, AAA). AA asks 4.5:1 for body text and 3:1 for large text; AAA asks 7:1.
Named colors close to Blue
Open blue in the full tools
- Open in Color Converter — convert it to any other notation.
- Open in Palette Generator — export its scale as --blue-50 … --blue-950 tokens.
- Open in Color Harmonies — turn the wheel and compare OKLCH with HSL.
- Open in Contrast Checker — test it against any background, with the closest passing shade.
- Open in Color System Generator — derive a light and dark token set from it.
Or browse every named color from the color converter.