#377CB4
Closest named color: Windows Blue (#3778BF). oklch(56.8% 0.111 246.1), rgb(55, 124, 180).
Aa
Black text reads best on this color (4.70:1).
About this color
#377CB4 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.111 and its hue 246°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.023 away. Black text reads best on it, at 4.70:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.111) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.70:1 |
| White text | 4.46:1 |
Values
| HEX | #377CB4 |
| RGB | rgb(55, 124, 180) |
| HSL | hsl(207, 53%, 46%) |
| OKLCH | oklch(56.8% 0.111 246.1) |
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 #377CB4 | 4.46:1 | AA large text | Lc -76.2 | Fine for body text |
| Black text on #377CB4 | 4.70:1 | AA | Lc 33.4 | Non-text elements, placeholder text |
| #377CB4 text on white | 4.46:1 | AA large text | Lc 70.7 | Content text, not long reading |
| #377CB4 text on black | 4.70:1 | AA | Lc -31.0 | 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 600.
-
Step 50
50
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E2EBF3
oklch(93.6% 0.015 244.7)
-
Step 200
200
#CBDBEB
oklch(88.4% 0.028 248.1)
-
Step 300
300
#A7C5E0
oklch(81% 0.05 245.6)
-
Step 400
400
#77A6D0
oklch(70.8% 0.08 246.2)
-
Step 500
500
#518FC4
oklch(63.1% 0.103 246.2)
-
Step 600
600 (this color)
#377CB4
oklch(56.8% 0.111 246.1)
-
Step 700
700
#256597
oklch(49.1% 0.103 245.9)
-
Step 800
800
#21537B
oklch(42.8% 0.085 245.9)
-
Step 900
900
#204563
oklch(37.8% 0.067 245.4)
-
Step 950
950
#14283A
oklch(26.9% 0.043 247.2)
#377CB4 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) | #637EB6 | 0.046 |
| Deuteranopia (no green cones) | #5272B3 | 0.035 |
| Tritanopia (no blue cones) | #008990 | 0.081 |
| Achromatopsia (no color) | #777777 | 0.111 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #377CB4
#377CB4
oklch(56.8% 0.111 246.1)
- #A26822
#A26822
oklch(56.8% 0.111 66.5)
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 #377CB4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.023
- Nice Blue #107AB0 ΔE 0.023
- Steel Blue #4682B4 ΔE 0.023
- Flat Blue #3C73A8 ΔE 0.028
- Cool Blue #4984B8 ΔE 0.030
- Cerulean #457B9D ΔE 0.036
- Dull Blue #49759C ΔE 0.039
- Muted Blue #3B719F ΔE 0.040
Use #377CB4 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.