#6399BB
Closest named color: Greyblue (#77A1B5). oklch(65.8% 0.076 237.2), rgb(99, 153, 187).
Aa
Black text reads best on this color (6.80:1).
About this color
#6399BB is a medium-light, moderately saturated blue. In OKLCH its lightness is 66%, its chroma 0.076 and its hue 237°. Its hue sits on the cool side of the wheel. The nearest named color is Greyblue (#77A1B5), ΔE 0.036 away. Black text reads best on it, at 6.80:1.
| Hue family | Blues |
| Lightness | medium-light (66%) |
| Chroma | moderately saturated (0.076) |
| Temperature | cool |
| Nearest name | Greyblue (#77A1B5) |
| Black text | 6.80:1 |
| White text | 3.08:1 |
Values
| HEX | #6399BB |
| RGB | rgb(99, 153, 187) |
| HSL | hsl(203, 39%, 56%) |
| OKLCH | oklch(65.8% 0.076 237.2) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #6399BB | 3.08:1 | AA large text | Lc -63.1 | Content text, not long reading |
| Black text on #6399BB | 6.80:1 | AA | Lc 46.4 | Large or bold text, headings |
| #6399BB text on white | 3.08:1 | AA large text | Lc 57.7 | Large or bold text, headings |
| #6399BB text on black | 6.80:1 | AA | Lc -44.1 | Non-text elements, placeholder text |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 500.
-
Step 50
50
#F2F6F8
oklch(97.1% 0.005 228.8)
-
Step 100
100
#E3EBF0
oklch(93.5% 0.011 234.8)
-
Step 200
200
#CDDCE5
oklch(88.6% 0.02 233.9)
-
Step 300
300
#ABC5D6
oklch(80.9% 0.037 236.6)
-
Step 400
400
#7DA7C2
oklch(70.8% 0.06 236.9)
-
Step 500
500 (this color)
#6399BB
oklch(65.8% 0.076 237.2)
-
Step 600
600
#3F7A9E
oklch(55.5% 0.083 237.6)
-
Step 700
700
#306787
oklch(49.1% 0.077 236.8)
-
Step 800
800
#29546E
oklch(42.7% 0.064 237.4)
-
Step 900
900
#264659
oklch(37.8% 0.05 236.2)
-
Step 950
950
#172934
oklch(27.1% 0.031 236.4)
#6399BB with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #8A98BD | 0.047 |
| Deuteranopia (no green cones) | #7D8FBA | 0.038 |
| Tritanopia (no blue cones) | #3BA2A4 | 0.060 |
| Achromatopsia (no color) | #939393 | 0.077 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #6399BB
#6399BB
oklch(65.8% 0.076 237.2)
- #B68663
#B68663
oklch(65.9% 0.077 57)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #6399BB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Greyblue #77A1B5 ΔE 0.036
- Faded Blue #658CBB ΔE 0.037
- Silver Lake Blue #778DA9 ΔE 0.040
- Blue Grey #758DA3 ΔE 0.043
- Cadet Blue #5F9EA0 ΔE 0.048
- Cool Gray #8D99AE ΔE 0.053
- Bluey Grey #89A0B0 ΔE 0.054
- Bluegrey #85A3B2 ΔE 0.054
Use #6399BB in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.