#377AAB
Closest named color: Flat Blue (#3C73A8). oklch(55.8% 0.102 243.3), rgb(55, 122, 171).
Aa
White text reads best on this color (4.63:1).
About this color
#377AAB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.102 and its hue 243°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.020 away. White text reads best on it, at 4.63:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.102) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.53:1 |
| White text | 4.63:1 |
Values
| HEX | #377AAB |
| RGB | rgb(55, 122, 171) |
| HSL | hsl(205, 51%, 44%) |
| OKLCH | oklch(55.8% 0.102 243.3) |
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 #377AAB | 4.63:1 | AA | Lc -77.4 | Fine for body text |
| Black text on #377AAB | 4.53:1 | AA | Lc 32.2 | Non-text elements, placeholder text |
| #377AAB text on white | 4.63:1 | AA | Lc 71.9 | Content text, not long reading |
| #377AAB text on black | 4.53:1 | AA | Lc -29.8 | 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
#E3EBF2
oklch(93.6% 0.013 244.3)
-
Step 200
200
#CBDCE9
oklch(88.6% 0.026 240.7)
-
Step 300
300
#A8C5DD
oklch(81% 0.046 243.3)
-
Step 400
400
#78A6CB
oklch(70.6% 0.074 243.3)
-
Step 500
500
#5490BE
oklch(63.2% 0.094 243.2)
-
Step 600
600 (this color)
#377AAB
oklch(55.8% 0.102 243.3)
-
Step 700
700
#286692
oklch(49.1% 0.095 243.1)
-
Step 800
800
#235377
oklch(42.7% 0.079 244)
-
Step 900
900
#224560
oklch(37.7% 0.062 243.8)
-
Step 950
950
#152938
oklch(27.2% 0.038 242.4)
#377AAB 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) | #647BAD | 0.048 |
| Deuteranopia (no green cones) | #5470AA | 0.037 |
| Tritanopia (no blue cones) | #00868B | 0.074 |
| Achromatopsia (no color) | #757575 | 0.102 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #377AAB
#377AAB
oklch(55.8% 0.102 243.3)
- #9E662C
#9E662C
oklch(56% 0.103 63.7)
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 #377AAB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.020
- Nice Blue #107AB0 ΔE 0.021
- Cerulean #457B9D ΔE 0.025
- Dull Blue #49759C ΔE 0.027
- Muted Blue #3B719F ΔE 0.028
- Steel Blue #4682B4 ΔE 0.030
- Stormy Blue #507B9C ΔE 0.033
- Windows Blue #3778BF ΔE 0.033
Use #377AAB 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.