#377B9E
Closest named color: Cerulean (#457B9D). oklch(55.4% 0.087 233.9), rgb(55, 123, 158).
Aa
White text reads best on this color (4.67:1).
About this color
#377B9E is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.087 and its hue 234°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean (#457B9D), ΔE 0.012 away. White text reads best on it, at 4.67:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.087) |
| Temperature | cool |
| Nearest name | Cerulean (#457B9D) |
| Black text | 4.48:1 |
| White text | 4.67:1 |
Values
| HEX | #377B9E |
| RGB | rgb(55, 123, 158) |
| HSL | hsl(200, 48%, 42%) |
| OKLCH | oklch(55.4% 0.087 233.9) |
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 #377B9E | 4.67:1 | AA | Lc -77.7 | Fine for body text |
| Black text on #377B9E | 4.48:1 | AA large text | Lc 31.8 | Non-text elements, placeholder text |
| #377B9E text on white | 4.67:1 | AA | Lc 72.3 | Content text, not long reading |
| #377B9E text on black | 4.48:1 | AA large text | Lc -29.4 | Dividers and decoration only |
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 600.
-
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
#CCDCE6
oklch(88.5% 0.022 235)
-
Step 300
300
#A9C5D6
oklch(80.8% 0.039 234.6)
-
Step 400
400
#79A8C2
oklch(70.7% 0.063 233)
-
Step 500
500
#5592B3
oklch(63.2% 0.081 233.7)
-
Step 600
600 (this color)
#377B9E
oklch(55.4% 0.087 233.9)
-
Step 700
700
#296888
oklch(49.1% 0.082 234.1)
-
Step 800
800
#24556E
oklch(42.7% 0.067 233.6)
-
Step 900
900
#234659
oklch(37.7% 0.052 234.2)
-
Step 950
950
#152934
oklch(26.9% 0.033 233.9)
#377B9E 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) | #6A7AA0 | 0.056 |
| Deuteranopia (no green cones) | #5C6F9D | 0.048 |
| Tritanopia (no blue cones) | #008487 | 0.057 |
| Achromatopsia (no color) | #747474 | 0.087 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #377B9E
#377B9E
oklch(55.4% 0.087 233.9)
- #9B643F
#9B643F
oklch(55.5% 0.088 53.8)
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 #377B9E, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.012
- Dull Blue #49759C ΔE 0.022
- Stormy Blue #507B9C ΔE 0.023
- Muted Blue #3B719F ΔE 0.030
- Flat Blue #3C73A8 ΔE 0.032
- Ocean #017B92 ΔE 0.033
- Metallic Blue #4F738E ΔE 0.033
- Nice Blue #107AB0 ΔE 0.034
Use #377B9E 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.