#337FF4
Closest named color: Clear Blue (#247AFD). oklch(61.3% 0.191 259.1), rgb(51, 127, 244).
Aa
Black text reads best on this color (5.48:1).
About this color
#337FF4 is a medium-dark, vivid blue. In OKLCH its lightness is 61%, its chroma 0.191 and its hue 259°. Its hue sits on the cool side of the wheel. The nearest named color is Clear Blue (#247AFD), ΔE 0.022 away. Black text reads best on it, at 5.48:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | vivid (0.191) |
| Temperature | cool |
| Nearest name | Clear Blue (#247AFD) |
| Black text | 5.48:1 |
| White text | 3.83:1 |
Values
| HEX | #337FF4 |
| RGB | rgb(51, 127, 244) |
| HSL | hsl(216, 90%, 58%) |
| OKLCH | oklch(61.3% 0.191 259.1) |
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 #337FF4 | 3.83:1 | AA large text | Lc -70.8 | Content text, not long reading |
| Black text on #337FF4 | 5.48:1 | AA | Lc 38.8 | Non-text elements, placeholder text |
| #337FF4 text on white | 3.83:1 | AA large text | Lc 65.3 | Content text, not long reading |
| #337FF4 text on black | 5.48:1 | AA | Lc -36.4 | 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 500.
-
Step 50
50
#F0F6FE
oklch(97.1% 0.012 255.5)
-
Step 100
100
#DFEBFC
oklch(93.6% 0.026 257)
-
Step 200
200
#C5DBFC
oklch(88.6% 0.051 258.4)
-
Step 300
300
#9CC2FD
oklch(80.8% 0.094 259)
-
Step 400
400
#65A0FD
oklch(70.7% 0.15 259.2)
-
Step 500
500 (this color)
#337FF4
oklch(61.3% 0.191 259.1)
-
Step 600
600
#0F6BE9
oklch(55.6% 0.207 259)
-
Step 700
700
#0058CA
oklch(49.1% 0.191 259.1)
-
Step 800
800
#0749A4
oklch(42.8% 0.159 259)
-
Step 900
900
#113E82
oklch(37.7% 0.125 259.1)
-
Step 950
950
#0C254C
oklch(27% 0.079 259.2)
#337FF4 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) | #3B8CF8 | 0.035 |
| Deuteranopia (no green cones) | #007AF2 | 0.025 |
| Tritanopia (no blue cones) | #009BAE | 0.146 |
| Achromatopsia (no color) | #828282 | 0.191 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337FF4
#337FF4
oklch(61.3% 0.191 259.1)
- #AC7900
#AC7900
oklch(61.2% 0.127 79.1)
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 #337FF4, closest first.
No curated palette has a color within ΔE 0.04 of #337FF4.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Clear Blue #247AFD ΔE 0.022
- Dodger Blue #1E90FF ΔE 0.044
- Cerulean Blue #056EEE ΔE 0.051
- Dark Sky Blue #448EE4 ΔE 0.052
- Cornflower #6A79F7 ΔE 0.053
- Soft Blue #6488EA ΔE 0.056
- Royal Blue #4169E1 ΔE 0.058
- Chefchaouen Blue #4895EF ΔE 0.064
Use #337FF4 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.