#a9d521
a balanced, vivid green · warm · closest name: Yellow Green
At a glance
Every number on this page in one read: what #a9d521 is made of, how bright it looks, and which way it leans.
Reads warm. Warm and cool siblings keep the same lightness, so you can swap one in without redoing your contrast maths.
Every format
| HEX | #a9d521 |
| RGB | rgb(169, 213, 33) |
| HSL | hsl(75, 73%, 48%) |
| CMYK | cmyk(21%, 0%, 85%, 17%) |
| LAB | lab(79.7 -36.4 74.3) |
| LCH | lch(79.7 82.8 116.1) |
| OKLCH | oklch(0.813 0.193 123.7) |
| Decimal | 11130145 |
| Display P3 | color(display-p3 0.663 0.835 0.129) |
Copy-ready code
/* CSS */
color: #a9d521;
background-color: #a9d521;
/* Tailwind (arbitrary) */
class="text-[#a9d521] bg-[#a9d521]"
/* SCSS */
$brand: #a9d521;
/* SwiftUI */
Color(red: 0.663, green: 0.835, blue: 0.129)
/* Android */
Color.parseColor("#a9d521")
/* Flutter */
Color(0xFFA9D521)
/* Python / OpenCV (BGR) */
(33, 213, 169)Best text color
Only one of black and white can be right. This is the one, with the number that proves it.
Accessibility — WCAG contrast
Color scale — 50 to 950
A Tailwind-shaped ramp built around this exact hex. #a9d521 is pinned to step 600; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.
:root {
--brand-50: #FAFCF3;
--brand-100: #F4F8E7;
--brand-200: #E9F3C8;
--brand-300: #DCF09E;
--brand-400: #CAE86D;
--brand-500: #B9E13D;
--brand-600: #a9d521;
--brand-700: #8CB11B;
--brand-800: #708D16;
--brand-900: #526614;
--brand-950: #33400C;
--brand: #a9d521;
--brand-ink: #000000;
}Colors that work with #a9d521
Not a palette — a role sheet. Each swatch answers one question you will hit while building the component.
Surface, border, heading and body all derive from this one hue, so the screen stays coherent without a second palette.
Lightness flips, hue holds. The accent stays the anchor in both themes.
How to use #a9d521
Derived from its contrast, chroma and lightness — not from taste.
- ✓Text and icons on dark surfaces
- ✓Primary buttons and calls to action
- ✓Focus rings, active and selected states
- ✓Brand accents, badges and data highlights
- ⚠Text of any size on white — fails WCAG AA
- ⚠Full-page backgrounds — tiring over long sessions
- ⚠Pairing with a same-lightness hue — edges vibrate
Similar colors
One move away from this hex in each direction. Every swatch is its own page.
Color relationships
The wheel positions with their names attached, so you can grab the one you actually need.
| Complementary | #4D21D5 | Directly opposite — maximum tension | |
| Analogous left | #D5A721 | Neighbour, quieter | |
| Analogous right | #4FD521 | Neighbour, quieter | |
| Split-complement 1 | #214FD5 | Contrast without the clash | |
| Split-complement 2 | #A721D5 | Contrast without the clash | |
| Triadic 1 | #21A9D5 | Even thirds — balanced and loud | |
| Triadic 2 | #D521A9 | Even thirds — balanced and loud | |
| Tetradic | #21D5A7 | Fourth corner of the square scheme |
RGB percentages
CMYK percentages
Color previews
#a9d521 text on a black background
contrast 12.23:1
#a9d521 text on a white background
contrast 1.72:1
CSS3 live lab
The quick brown fox
color: #a9d521;
background-color: #a9d521;
Glowing headline
text-shadow: 2px 2px 8px #a9d521;
Soft neon halo
text-shadow: 0 0 14px rgba(169, 213, 33, 0.45);
box-shadow: 0 12px 32px -8px rgba(169, 213, 33, 0.45);
border: 3px solid #a9d521; background: linear-gradient(135deg, #a9d521, #31D521);
Monochromatic scale
Palettes built from #a9d521
Shades — darker
Tints — lighter
Color harmonies
Nearest named colors
Ranked with CIEDE2000 across all 139 CSS keywords. Under ΔE 2 the eye stops telling them apart; over ΔE 10 they are plainly different colors.
Closest color with a full write-up: Spring Bud (#a7fc00) — ΔE2000 9 away, with its history, psychology and brand usage.
#a9d521 in the real world
Where a color in this family tends to land, and the interface roles it is usually asked to play.
Converts to four-color process without much drama. Proof it anyway.
#a9d521, answered
What color is #a9d521?
#a9d521 is a balanced vivid green, closest to Yellow Green (ΔE2000 3.4). It sits at 75° on the hue wheel with 73% saturation and 48% lightness, which reads as warm.
What is the RGB value of #a9d521?
rgb(169, 213, 33) — 169 red, 213 green and 33 blue out of 255, or 66.3% / 83.5% / 12.9% by channel.
Is #a9d521 a light or a dark color?
It is a light color. Relative luminance is 0.5613 and perceived brightness is 74%, so black text on it reaches 12.23:1.
Should I use black or white text on #a9d521?
Black. It scores 12.23:1 against #a9d521, versus 1.72:1 for white — AAA at any size.
What is the complementary color of #a9d521?
#4D21D5 sits directly opposite on the wheel. Softer options are the split-complements #214FD5 and #A721D5, which give the same contrast with far less vibration.
What colors go well with #a9d521?
For interface work: #F9FAF4 as the surface, #E2EDC0 for borders, #879B4B for secondary text, #1C1DDA as an accent and #586E11 for hover and pressed states. For a palette, the analogous pair #D5A721 and #4FD521 stays calm, while #4D21D5 is the loudest partner.
What is #a9d521 in CMYK for printing?
cmyk(21%, 0%, 85%, 17%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.
Is #a9d521 warm or cool?
Warm — it scores 37 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #D5BF21; nudged cooler, #66D71E.