#337BAF
Closest named color: Nice Blue (#107AB0). oklch(56.2% 0.108 243.4), rgb(51, 123, 175).
Aa
Black text reads best on this color (4.59:1).
About this color
#337BAF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.108 and its hue 243°. Its hue sits on the cool side of the wheel. The nearest named color is Nice Blue (#107AB0), ΔE 0.018 away. Black text reads best on it, at 4.59:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.108) |
| Temperature | cool |
| Nearest name | Nice Blue (#107AB0) |
| Black text | 4.59:1 |
| White text | 4.57:1 |
Values
| HEX | #337BAF |
| RGB | rgb(51, 123, 175) |
| HSL | hsl(205, 55%, 44%) |
| OKLCH | oklch(56.2% 0.108 243.4) |
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 #337BAF | 4.57:1 | AA | Lc -76.9 | Fine for body text |
| Black text on #337BAF | 4.59:1 | AA | Lc 32.6 | Non-text elements, placeholder text |
| #337BAF text on white | 4.57:1 | AA | Lc 71.5 | Content text, not long reading |
| #337BAF text on black | 4.59:1 | AA | Lc -30.2 | 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
#A7C5DE
oklch(81% 0.048 243.5)
-
Step 400
400
#76A7CE
oklch(70.8% 0.078 243.1)
-
Step 500
500
#5090C1
oklch(63.1% 0.099 243.4)
-
Step 600
600 (this color)
#337BAF
oklch(56.2% 0.108 243.4)
-
Step 700
700
#236695
oklch(49.1% 0.1 243.5)
-
Step 800
800
#1F5379
oklch(42.6% 0.084 243.9)
-
Step 900
900
#204561
oklch(37.7% 0.064 243.6)
-
Step 950
950
#132939
oklch(27.1% 0.041 242)
#337BAF 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) | #637CB1 | 0.049 |
| Deuteranopia (no green cones) | #5270AE | 0.039 |
| Tritanopia (no blue cones) | #00888D | 0.078 |
| Achromatopsia (no color) | #767676 | 0.108 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337BAF
#337BAF
oklch(56.2% 0.108 243.4)
- #A16527
#A16527
oklch(56.1% 0.108 62.8)
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 #337BAF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Nice Blue #107AB0 ΔE 0.018
- Flat Blue #3C73A8 ΔE 0.023
- Steel Blue #4682B4 ΔE 0.028
- Windows Blue #3778BF ΔE 0.029
- Cerulean #457B9D ΔE 0.031
- Dull Blue #49759C ΔE 0.033
- Muted Blue #3B719F ΔE 0.033
- Cool Blue #4984B8 ΔE 0.036
Use #337BAF 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.