#377AA4
Closest named color: Cerulean (#457B9D). oklch(55.5% 0.094 239.2), rgb(55, 122, 164).
Aa
White text reads best on this color (4.68:1).
About this color
#377AA4 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.094 and its hue 239°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean (#457B9D), ΔE 0.017 away. White text reads best on it, at 4.68:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.094) |
| Temperature | cool |
| Nearest name | Cerulean (#457B9D) |
| Black text | 4.48:1 |
| White text | 4.68:1 |
Values
| HEX | #377AA4 |
| RGB | rgb(55, 122, 164) |
| HSL | hsl(203, 50%, 43%) |
| OKLCH | oklch(55.5% 0.094 239.2) |
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 #377AA4 | 4.68:1 | AA | Lc -77.8 | Fine for body text |
| Black text on #377AA4 | 4.48:1 | AA large text | Lc 31.8 | Non-text elements, placeholder text |
| #377AA4 text on white | 4.68:1 | AA | Lc 72.3 | Content text, not long reading |
| #377AA4 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
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E3EBF1
oklch(93.6% 0.012 239.9)
-
Step 200
200
#CCDCE7
oklch(88.6% 0.023 237.7)
-
Step 300
300
#A8C5D9
oklch(80.8% 0.042 238.2)
-
Step 400
400
#79A7C7
oklch(70.7% 0.068 239.3)
-
Step 500
500
#5591B8
oklch(63.2% 0.086 238.7)
-
Step 600
600 (this color)
#377AA4
oklch(55.5% 0.094 239.2)
-
Step 700
700
#29678D
oklch(49.1% 0.088 239.1)
-
Step 800
800
#245472
oklch(42.7% 0.072 239)
-
Step 900
900
#23465C
oklch(37.8% 0.055 238.2)
-
Step 950
950
#152936
oklch(27% 0.036 238.5)
#377AA4 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) | #677AA6 | 0.052 |
| Deuteranopia (no green cones) | #586FA3 | 0.043 |
| Tritanopia (no blue cones) | #008588 | 0.067 |
| Achromatopsia (no color) | #747474 | 0.094 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #377AA4
#377AA4
oklch(55.5% 0.094 239.2)
- #9B6536
#9B6536
oklch(55.5% 0.094 60)
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 #377AA4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.017
- Dull Blue #49759C ΔE 0.021
- Flat Blue #3C73A8 ΔE 0.023
- Muted Blue #3B719F ΔE 0.025
- Nice Blue #107AB0 ΔE 0.026
- Stormy Blue #507B9C ΔE 0.027
- Steel Blue #4682B4 ΔE 0.035
- Metallic Blue #4F738E ΔE 0.039
Use #377AA4 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.