#313B66
Closest named color: Prussian Blue (#1D3557). oklch(36.5% 0.075 272.3), rgb(49, 59, 102).
Aa
White text reads best on this color (10.78:1).
About this color
#313B66 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.075 and its hue 272°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.043 away. White text reads best on it, at 10.78:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.075) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.94:1 |
| White text | 10.78:1 |
Values
| HEX | #313B66 |
| RGB | rgb(49, 59, 102) |
| HSL | hsl(229, 35%, 30%) |
| OKLCH | oklch(36.5% 0.075 272.3) |
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 #313B66 | 10.78:1 | AAA | Lc -98.8 | Preferred for body text |
| Black text on #313B66 | 1.94:1 | Fails | Lc 9.0 | Not readable |
| #313B66 text on white | 10.78:1 | AAA | Lc 94.9 | Preferred for body text |
| #313B66 text on black | 1.94:1 | Fails | Lc -7.7 | Not readable |
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 900.
-
Step 50
50
#F3F5FB
oklch(97% 0.008 271.3)
-
Step 100
100
#E6E9F5
oklch(93.5% 0.016 274.8)
-
Step 200
200
#D2D8EF
oklch(88.5% 0.032 274.1)
-
Step 300
300
#B4BFE6
oklch(80.9% 0.056 272.7)
-
Step 400
400
#8D9DD9
oklch(70.6% 0.09 272.4)
-
Step 500
500
#7284CF
oklch(63.1% 0.115 272.5)
-
Step 600
600
#5B6CBC
oklch(55.5% 0.126 272.7)
-
Step 700
700
#4B5AA2
oklch(49.1% 0.116 272.6)
-
Step 800
800
#3D4A84
oklch(42.7% 0.097 272.2)
-
Step 900
900 (this color)
#313B66
oklch(36.5% 0.075 272.3)
-
Step 950
950
#1E253E
oklch(27.1% 0.048 271.1)
#313B66 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) | #2A4068 | 0.016 |
| Deuteranopia (no green cones) | #253B65 | 0.016 |
| Tritanopia (no blue cones) | #1C444B | 0.067 |
| Achromatopsia (no color) | #3D3D3D | 0.076 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #313B66
#313B66
oklch(36.5% 0.075 272.3)
- #4C3D00
#4C3D00
oklch(36.5% 0.075 93.2)
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 #313B66, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.043
- Dark Grey Blue #29465B ΔE 0.044
- Marine Blue #01386A ΔE 0.048
- Twilight Blue #0A437A ΔE 0.048
- Dark Blue Grey #1F3B4D ΔE 0.052
- Charcoal #264653 ΔE 0.056
- Midnight Green #073B4C ΔE 0.066
- Onyx #343A40 ΔE 0.067
Use #313B66 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.