#307FB4
Closest named color: Steel Blue (#4682B4). oklch(57.3% 0.112 242), rgb(48, 127, 180).
Aa
Black text reads best on this color (4.82:1).
About this color
#307FB4 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.112 and its hue 242°. 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 4.82:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.112) |
| Temperature | cool |
| Nearest name | Steel Blue (#4682B4) |
| Black text | 4.82:1 |
| White text | 4.35:1 |
Values
| HEX | #307FB4 |
| RGB | rgb(48, 127, 180) |
| HSL | hsl(204, 58%, 45%) |
| OKLCH | oklch(57.3% 0.112 242) |
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 #307FB4 | 4.35:1 | AA large text | Lc -75.4 | Fine for body text |
| Black text on #307FB4 | 4.82:1 | AA | Lc 34.2 | Non-text elements, placeholder text |
| #307FB4 text on white | 4.35:1 | AA large text | Lc 69.9 | Content text, not long reading |
| #307FB4 text on black | 4.82:1 | AA | Lc -31.8 | 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
#CADCEA
oklch(88.5% 0.027 241.2)
-
Step 300
300
#A5C5DF
oklch(80.9% 0.05 242.9)
-
Step 400
400
#73A7CF
oklch(70.7% 0.081 242.4)
-
Step 500
500
#4B91C2
oklch(63.2% 0.102 241.4)
-
Step 600
600 (this color)
#307FB4
oklch(57.3% 0.112 242)
-
Step 700
700
#1B6696
oklch(49% 0.104 242.3)
-
Step 800
800
#1A547A
oklch(42.8% 0.086 241.9)
-
Step 900
900
#1D4562
oklch(37.6% 0.067 242.9)
-
Step 950
950
#122939
oklch(27% 0.042 241)
#307FB4 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) | #6780B6 | 0.055 |
| Deuteranopia (no green cones) | #5473B3 | 0.043 |
| Tritanopia (no blue cones) | #008C92 | 0.077 |
| Achromatopsia (no color) | #797979 | 0.112 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #307FB4
#307FB4
oklch(57.3% 0.112 242)
- #A66728
#A66728
oklch(57.2% 0.111 61.8)
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 #307FB4, 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 0.023
- Cool Blue #4984B8 ΔE 0.027
- Windows Blue #3778BF ΔE 0.029
- Blue NCS #118AB2 ΔE 0.034
- Flat Blue #3C73A8 ΔE 0.035
- Cerulean #457B9D ΔE 0.036
- Water Blue #0E87CC ΔE 0.039
Use #307FB4 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.