#377DB4
Closest named color: Steel Blue (#4682B4). oklch(57% 0.11 245.3), rgb(55, 125, 180).
Aa
Black text reads best on this color (4.75:1).
About this color
#377DB4 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.110 and its hue 245°. Its hue sits on the cool side of the wheel. The nearest named color is Steel Blue (#4682B4), ΔE 0.021 away. Black text reads best on it, at 4.75:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.110) |
| Temperature | cool |
| Nearest name | Steel Blue (#4682B4) |
| Black text | 4.75:1 |
| White text | 4.41:1 |
Values
| HEX | #377DB4 |
| RGB | rgb(55, 125, 180) |
| HSL | hsl(206, 53%, 46%) |
| OKLCH | oklch(57% 0.11 245.3) |
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 #377DB4 | 4.41:1 | AA large text | Lc -75.8 | Fine for body text |
| Black text on #377DB4 | 4.75:1 | AA | Lc 33.7 | Non-text elements, placeholder text |
| #377DB4 text on white | 4.41:1 | AA large text | Lc 70.4 | Content text, not long reading |
| #377DB4 text on black | 4.75:1 | AA | Lc -31.3 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E2EBF3
oklch(93.6% 0.015 244.7)
-
Step 200
200
#CBDCEB
oklch(88.6% 0.028 244.7)
-
Step 300
300
#A7C5DF
oklch(81% 0.049 244.6)
-
Step 400
400
#76A6CF
oklch(70.7% 0.079 245)
-
Step 500
500
#518FC3
oklch(63% 0.102 245.7)
-
Step 600
600 (this color)
#377DB4
oklch(57% 0.11 245.3)
-
Step 700
700
#246597
oklch(49% 0.103 245.6)
-
Step 800
800
#20537A
oklch(42.7% 0.084 244.9)
-
Step 900
900
#204562
oklch(37.7% 0.066 244.5)
-
Step 950
950
#14283A
oklch(26.9% 0.043 247.2)
#377DB4 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) | #647FB6 | 0.047 |
| Deuteranopia (no green cones) | #5373B3 | 0.035 |
| Tritanopia (no blue cones) | #008A90 | 0.081 |
| Achromatopsia (no color) | #787878 | 0.110 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #377DB4
#377DB4
oklch(57% 0.11 245.3)
- #A36825
#A36825
oklch(56.9% 0.11 65.1)
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 #377DB4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Steel Blue #4682B4 ΔE 0.021
- Nice Blue #107AB0 ΔE 0.024
- Windows Blue #3778BF ΔE 0.025
- Cool Blue #4984B8 ΔE 0.027
- Flat Blue #3C73A8 ΔE 0.030
- Cerulean #457B9D ΔE 0.036
- Off Blue #5684AE ΔE 0.039
- Dull Blue #49759C ΔE 0.040
Use #377DB4 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.