#3991CB
Closest named color: Water Blue (#0E87CC). oklch(63% 0.12 241.4), rgb(57, 145, 203).
Aa
Black text reads best on this color (6.08:1).
About this color
#3991CB is a medium-light, moderately saturated blue. In OKLCH its lightness is 63%, its chroma 0.120 and its hue 241°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.037 away. Black text reads best on it, at 6.08:1.
| Hue family | Blues |
| Lightness | medium-light (63%) |
| Chroma | moderately saturated (0.120) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 6.08:1 |
| White text | 3.45:1 |
Values
| HEX | #3991CB |
| RGB | rgb(57, 145, 203) |
| HSL | hsl(204, 58%, 51%) |
| OKLCH | oklch(63% 0.12 241.4) |
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 #3991CB | 3.45:1 | AA large text | Lc -67.2 | Content text, not long reading |
| Black text on #3991CB | 6.08:1 | AA | Lc 42.4 | Non-text elements, placeholder text |
| #3991CB text on white | 3.45:1 | AA large text | Lc 61.7 | Content text, not long reading |
| #3991CB text on black | 6.08:1 | AA | Lc -40.0 | 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
#F1F6FA
oklch(97.1% 0.008 241.7)
-
Step 100
100
#E0ECF4
oklch(93.6% 0.017 236.7)
-
Step 200
200
#C7DCED
oklch(88.4% 0.033 242.4)
-
Step 300
300
#9FC6E4
oklch(80.9% 0.06 241.6)
-
Step 400
400
#69A8D6
oklch(70.7% 0.094 241.5)
-
Step 500
500 (this color)
#3991CB
oklch(63% 0.12 241.4)
-
Step 600
600
#007AB8
oklch(55.5% 0.131 241.7)
-
Step 700
700
#00679C
oklch(49.2% 0.116 241.5)
-
Step 800
800
#005480
oklch(42.6% 0.1 241.3)
-
Step 900
900
#104667
oklch(37.7% 0.078 241)
-
Step 950
950
#0C293C
oklch(26.9% 0.049 240.9)
#3991CB 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) | #7692CE | 0.060 |
| Deuteranopia (no green cones) | #6284CA | 0.047 |
| Tritanopia (no blue cones) | #009FA5 | 0.083 |
| Achromatopsia (no color) | #8A8A8A | 0.121 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3991CB
#3991CB
oklch(63% 0.12 241.4)
- #BD7632
#BD7632
oklch(63% 0.121 61)
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 #3991CB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.037
- Cool Blue #4984B8 ΔE 0.041
- Dark Sky Blue #448EE4 ΔE 0.042
- Faded Blue #658CBB ΔE 0.043
- Blue NCS #118AB2 ΔE 0.047
- Steel Blue #4682B4 ΔE 0.048
- Off Blue #5684AE ΔE 0.051
- Dusty Blue #5A86AD ΔE 0.051
Use #3991CB 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.