#307DB8
Closest named color: Windows Blue (#3778BF). oklch(57% 0.118 245.3), rgb(48, 125, 184).
Aa
Black text reads best on this color (4.75:1).
About this color
#307DB8 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.118 and its hue 245°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.020 away. Black text reads best on it, at 4.75:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.118) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.75:1 |
| White text | 4.41:1 |
Values
| HEX | #307DB8 |
| RGB | rgb(48, 125, 184) |
| HSL | hsl(206, 59%, 45%) |
| OKLCH | oklch(57% 0.118 245.3) |
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 #307DB8 | 4.41:1 | AA large text | Lc -75.8 | Fine for body text |
| Black text on #307DB8 | 4.75:1 | AA | Lc 33.8 | Non-text elements, placeholder text |
| #307DB8 text on white | 4.41:1 | AA large text | Lc 70.3 | Content text, not long reading |
| #307DB8 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
#E2EBF4
oklch(93.6% 0.016 248)
-
Step 200
200
#CADCEC
oklch(88.6% 0.029 244.9)
-
Step 300
300
#A5C5E1
oklch(80.9% 0.053 244.9)
-
Step 400
400
#73A6D2
oklch(70.6% 0.085 245.4)
-
Step 500
500
#4C8FC7
oklch(63% 0.109 245.9)
-
Step 600
600 (this color)
#307DB8
oklch(57% 0.118 245.3)
-
Step 700
700
#1D659A
oklch(49% 0.109 245.5)
-
Step 800
800
#1B537D
oklch(42.7% 0.09 245.2)
-
Step 900
900
#1D4565
oklch(37.8% 0.071 245.5)
-
Step 950
950
#12283B
oklch(26.9% 0.045 246.6)
#307DB8 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) | #627FBB | 0.050 |
| Deuteranopia (no green cones) | #4F72B7 | 0.038 |
| Tritanopia (no blue cones) | #008B92 | 0.084 |
| Achromatopsia (no color) | #787878 | 0.118 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #307DB8
#307DB8
oklch(57% 0.118 245.3)
- #A6671A
#A6671A
oklch(57.1% 0.118 65.3)
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 #307DB8, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.020
- Nice Blue #107AB0 ΔE 0.023
- Steel Blue #4682B4 ΔE 0.026
- Cool Blue #4984B8 ΔE 0.031
- Flat Blue #3C73A8 ΔE 0.033
- Water Blue #0E87CC ΔE 0.037
- Blue NCS #118AB2 ΔE 0.042
- Cerulean #457B9D ΔE 0.043
Use #307DB8 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.