#51C866
Closest named color: Algae Green (#21C36F). oklch(74.2% 0.174 147), rgb(81, 200, 102).
Aa
Black text reads best on this color (9.80:1).
About this color
#51C866 is a medium-light, vivid green. In OKLCH its lightness is 74%, its chroma 0.174 and its hue 147°. Its hue sits between the warm and cool halves of the wheel. The nearest named color is Algae Green (#21C36F), ΔE 0.030 away. Black text reads best on it, at 9.80:1.
| Hue family | Greens |
| Lightness | medium-light (74%) |
| Chroma | vivid (0.174) |
| Temperature | in between |
| Nearest name | Algae Green (#21C36F) |
| Black text | 9.80:1 |
| White text | 2.14:1 |
Values
| HEX | #51C866 |
| RGB | rgb(81, 200, 102) |
| HSL | hsl(131, 52%, 55%) |
| OKLCH | oklch(74.2% 0.174 147) |
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 #51C866 | 2.14:1 | Fails | Lc -46.4 | Large or bold text, headings |
| Black text on #51C866 | 9.80:1 | AAA | Lc 62.2 | Content text, not long reading |
| #51C866 text on white | 2.14:1 | Fails | Lc 41.7 | Non-text elements, placeholder text |
| #51C866 text on black | 9.80:1 | AAA | Lc -60.5 | Content text, not long reading |
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
#EFF8F0
oklch(97% 0.014 148.8)
-
Step 100
100
#DDF0DE
oklch(93.6% 0.031 146.8)
-
Step 200
200
#C0E5C2
oklch(88.6% 0.061 146.5)
-
Step 300
300
#91D497
oklch(80.9% 0.109 146.7)
-
Step 400
400 (this color)
#51C866
oklch(74.2% 0.174 147)
-
Step 500
500
#00A63B
oklch(63.2% 0.188 146.9)
-
Step 600
600
#008B31
oklch(55.5% 0.165 147.1)
-
Step 700
700
#007528
oklch(49% 0.145 147.1)
-
Step 800
800
#00601F
oklch(42.6% 0.127 147)
-
Step 900
900
#005019
oklch(37.6% 0.111 147.2)
-
Step 950
950
#00300B
oklch(26.9% 0.08 146.8)
#51C866 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) | #CAB85E | 0.136 |
| Deuteranopia (no green cones) | #BBAD6D | 0.135 |
| Tritanopia (no blue cones) | #35C4B1 | 0.102 |
| Achromatopsia (no color) | #B1B1B1 | 0.175 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #51C866
#51C866
oklch(74.2% 0.174 147)
- #E480E4
#E480E4
oklch(74.3% 0.174 327.2)
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 #51C866, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Algae Green #21C36F ΔE 0.030
- Seaweed #18D17B ΔE 0.031
- Dark Mint #48C072 ΔE 0.031
- Soft Green #6FC276 ΔE 0.039
- Dark Mint Green #20C073 ΔE 0.039
- Apple #6ECB3C ΔE 0.043
- Turtle Green #75B84F ΔE 0.047
- Shamrock Green #02C14D ΔE 0.047
Use #51C866 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.