#51AFEE
Closest named color: Deep Sky Blue (#00BFFF). oklch(72.4% 0.128 241), rgb(81, 175, 238).
Aa
Black text reads best on this color (8.71:1).
About this color
#51AFEE is a medium-light, moderately saturated blue. In OKLCH its lightness is 72%, its chroma 0.128 and its hue 241°. Its hue sits on the cool side of the wheel. The nearest named color is Deep Sky Blue (#00BFFF), ΔE 0.047 away. Black text reads best on it, at 8.71:1.
| Hue family | Blues |
| Lightness | medium-light (72%) |
| Chroma | moderately saturated (0.128) |
| Temperature | cool |
| Nearest name | Deep Sky Blue (#00BFFF) |
| Black text | 8.71:1 |
| White text | 2.40:1 |
Values
| HEX | #51AFEE |
| RGB | rgb(81, 175, 238) |
| HSL | hsl(204, 82%, 63%) |
| OKLCH | oklch(72.4% 0.128 241) |
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 #51AFEE | 2.40:1 | Fails | Lc -52.1 | Large or bold text, headings |
| Black text on #51AFEE | 8.71:1 | AAA | Lc 56.8 | Large or bold text, headings |
| #51AFEE text on white | 2.40:1 | Fails | Lc 47.2 | Large or bold text, headings |
| #51AFEE text on black | 8.71:1 | AAA | Lc -54.9 | Large or bold text, headings |
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 400.
-
Step 50
50
#EFF7FC
oklch(97.2% 0.011 234.8)
-
Step 100
100
#DDECF8
oklch(93.5% 0.023 241.9)
-
Step 200
200
#C0DEF4
oklch(88.6% 0.044 239.8)
-
Step 300
300
#92C8F0
oklch(81% 0.08 241)
-
Step 400
400 (this color)
#51AFEE
oklch(72.4% 0.128 241)
-
Step 500
500
#0092D9
oklch(63.1% 0.147 241)
-
Step 600
600
#007BB7
oklch(55.7% 0.129 240.7)
-
Step 700
700
#00679B
oklch(49.1% 0.115 241)
-
Step 800
800
#005480
oklch(42.6% 0.1 241.3)
-
Step 900
900
#00466B
oklch(37.7% 0.087 240.8)
-
Step 950
950
#002942
oklch(26.9% 0.063 241.6)
#51AFEE 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) | #92AFF1 | 0.065 |
| Deuteranopia (no green cones) | #7DA0ED | 0.053 |
| Tritanopia (no blue cones) | #00BFC5 | 0.091 |
| Achromatopsia (no color) | #A7A7A7 | 0.128 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #51AFEE
#51AFEE
oklch(72.4% 0.128 241)
- #DF924A
#DF924A
oklch(72.5% 0.128 61.5)
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 #51AFEE, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Deep Sky Blue #00BFFF ΔE 0.047
- Carolina Blue #8AB8FE ΔE 0.066
- Cornflower Blue #6495ED ΔE 0.070
- Vivid Sky Blue #4CC9F0 ΔE 0.071
- Chefchaouen Blue #4895EF ΔE 0.073
- Turquoise Blue #06B1C4 ΔE 0.075
- Bright Sky Blue #02CCFE ΔE 0.076
- Lightblue #7BC8F6 ΔE 0.082
Use #51AFEE 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.