#377CA9
Closest named color: Cerulean (#457B9D). oklch(56.2% 0.098 240.3), rgb(55, 124, 169).
Aa
Black text reads best on this color (4.61:1).
About this color
#377CA9 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.098 and its hue 240°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean (#457B9D), ΔE 0.021 away. Black text reads best on it, at 4.61:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.098) |
| Temperature | cool |
| Nearest name | Cerulean (#457B9D) |
| Black text | 4.61:1 |
| White text | 4.54:1 |
Values
| HEX | #377CA9 |
| RGB | rgb(55, 124, 169) |
| HSL | hsl(204, 51%, 44%) |
| OKLCH | oklch(56.2% 0.098 240.3) |
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 #377CA9 | 4.54:1 | AA | Lc -76.8 | Fine for body text |
| Black text on #377CA9 | 4.61:1 | AA | Lc 32.7 | Non-text elements, placeholder text |
| #377CA9 text on white | 4.54:1 | AA | Lc 71.3 | Content text, not long reading |
| #377CA9 text on black | 4.61:1 | AA | Lc -30.3 | 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 600.
-
Step 50
50
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E3EBF2
oklch(93.6% 0.013 244.3)
-
Step 200
200
#CBDCE8
oklch(88.5% 0.025 238.4)
-
Step 300
300
#A8C5DB
oklch(80.9% 0.044 240.9)
-
Step 400
400
#78A7C9
oklch(70.7% 0.071 240.4)
-
Step 500
500
#5391BB
oklch(63.2% 0.09 239.9)
-
Step 600
600 (this color)
#377CA9
oklch(56.2% 0.098 240.3)
-
Step 700
700
#27678F
oklch(49.2% 0.091 239.9)
-
Step 800
800
#225474
oklch(42.7% 0.075 240)
-
Step 900
900
#21455E
oklch(37.6% 0.06 241.1)
-
Step 950
950
#142937
oklch(27% 0.038 239.4)
#377CA9 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) | #677CAB | 0.051 |
| Deuteranopia (no green cones) | #5871A8 | 0.042 |
| Tritanopia (no blue cones) | #00878B | 0.070 |
| Achromatopsia (no color) | #767676 | 0.098 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #377CA9
#377CA9
oklch(56.2% 0.098 240.3)
- #9F6634
#9F6634
oklch(56.2% 0.098 59.9)
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 #377CA9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.021
- Nice Blue #107AB0 ΔE 0.024
- Flat Blue #3C73A8 ΔE 0.026
- Dull Blue #49759C ΔE 0.027
- Steel Blue #4682B4 ΔE 0.027
- Stormy Blue #507B9C ΔE 0.029
- Muted Blue #3B719F ΔE 0.032
- Cool Blue #4984B8 ΔE 0.036
Use #377CA9 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.