#377FB5
Closest named color: Steel Blue (#4682B4). oklch(57.6% 0.11 244.2), rgb(55, 127, 181).
Aa
Black text reads best on this color (4.86:1).
About this color
#377FB5 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 58%, its chroma 0.110 and its hue 244°. Its hue sits on the cool side of the wheel. The nearest named color is Steel Blue (#4682B4), ΔE 0.017 away. Black text reads best on it, at 4.86:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | moderately saturated (0.110) |
| Temperature | cool |
| Nearest name | Steel Blue (#4682B4) |
| Black text | 4.86:1 |
| White text | 4.31:1 |
Values
| HEX | #377FB5 |
| RGB | rgb(55, 127, 181) |
| HSL | hsl(206, 53%, 46%) |
| OKLCH | oklch(57.6% 0.11 244.2) |
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 #377FB5 | 4.31:1 | AA large text | Lc -75.1 | Fine for body text |
| Black text on #377FB5 | 4.86:1 | AA | Lc 34.5 | Non-text elements, placeholder text |
| #377FB5 text on white | 4.31:1 | AA large text | Lc 69.6 | Content text, not long reading |
| #377FB5 text on black | 4.86:1 | AA | Lc -32.1 | 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
#CBDCEA
oklch(88.6% 0.027 242.8)
-
Step 300
300
#A6C5DF
oklch(80.9% 0.05 243.7)
-
Step 400
400
#76A6CF
oklch(70.7% 0.079 245)
-
Step 500
500
#5090C2
oklch(63.2% 0.1 243.9)
-
Step 600
600 (this color)
#377FB5
oklch(57.6% 0.11 244.2)
-
Step 700
700
#226696
oklch(49.2% 0.102 243.8)
-
Step 800
800
#1F537A
oklch(42.7% 0.085 244.5)
-
Step 900
900
#1F4562
oklch(37.7% 0.066 243.9)
-
Step 950
950
#132939
oklch(27.1% 0.041 242)
#377FB5 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) | #6780B7 | 0.050 |
| Deuteranopia (no green cones) | #5574B4 | 0.039 |
| Tritanopia (no blue cones) | #008C92 | 0.079 |
| Achromatopsia (no color) | #7A7A7A | 0.110 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #377FB5
#377FB5
oklch(57.6% 0.11 244.2)
- #A56929
#A56929
oklch(57.4% 0.109 63.8)
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 #377FB5, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Steel Blue #4682B4 ΔE 0.017
- Cool Blue #4984B8 ΔE 0.023
- Nice Blue #107AB0 ΔE 0.028
- Windows Blue #3778BF ΔE 0.028
- Blue NCS #118AB2 ΔE 0.036
- Flat Blue #3C73A8 ΔE 0.036
- Off Blue #5684AE ΔE 0.036
- Cerulean #457B9D ΔE 0.037
Use #377FB5 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.