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yellow · warm

#c9e721

a balanced, electric yellow · warm · closest name: Green Yellow

Token name suggestion: Studio Brass

RGB
201, 231, 33
HSL
69°, 81%, 52%
CMYK
13, 0, 86, 9
Luminance
0.6968

#c9e721 is a balanced electric yellow, 69° on the wheel and 33/100 on the cool side. Put black text on it (14.94:1). As text it scores 1.41:1 on white — use #6B7B0D instead. Nearest name is Green Yellow, nearest Tailwind family is lime.

hsl(69 81% 52%)rgb(201 231 33)Base step 600AAA inkWarm

At a glance

Every number on this page in one read: what #c9e721 is made of, how bright it looks, and which way it leans.

Hex
#c9e721
Hue
69°
yellow
Saturation
81%
electric
Lightness
52%
balanced
Brightness
91%
HSV value
Perceived
82%
weighted brightness
Luminance
0.6968
WCAG relative
Temperature
Warm
33/100 cool
Color family
Yellow
Tone
Electric
Best ink
Black
14.94:1
Closest name
Green Yellow
ΔE2000 8.3
Chroma
87.2
LCH, 0–130ish
OKLCH L
0.876
perceptual lightness
Tailwind
lime
500 · ΔE 11.1
Web-safe
#CCFF33
nearest of 216
Where it sits
Hue69° of 360°
Saturation81%
Lightness52%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #c9e721.

Temperature
Warm ← → Cool33% cool

Reads warm. Warm and cool siblings keep the same lightness, so you can swap one in without redoing your contrast maths.

Luminance by channel
Red18%
Green82%
Blue0%

Green carries most of what the eye calls brightness — that is why WCAG weights it 0.7152.

Every format

HEX#c9e721
HEX (8-digit)#c9e721ff
RGBrgb(201, 231, 33)
RGBArgba(201, 231, 33, 1)
HSLhsl(69, 81%, 52%)
HSV / HSBhsv(69, 86%, 91%)
HWBhwb(69 13% 9%)
CMYKcmyk(13%, 0%, 86%, 9%)
LABlab(86.8 -31.9 81.2)
LCHlch(86.8 87.2 111.5)
OKLCHoklch(0.876 0.199 119.0)
XYZ (D65)xyz(52.94, 69.68, 12.10)
Decimal13231905
Display P3color(display-p3 0.788 0.906 0.129)
Web-safe#CCFF33

Copy-ready code

every platformclick to select
/* CSS */
color: #c9e721;
background-color: #c9e721;
/* CSS custom property */
--brand: #c9e721;
/* Tailwind (arbitrary) */
class="text-[#c9e721] bg-[#c9e721]"
/* SCSS */
$brand: #c9e721;
/* SwiftUI */
Color(red: 0.788, green: 0.906, blue: 0.129)
/* UIKit */
UIColor(red: 0.788, green: 0.906, blue: 0.129, alpha: 1)
/* Android XML */
<color name="brand">#C9E721</color>
/* Android Compose */
Color(0xFFC9E721)
/* Flutter */
Color(0xFFC9E721)
/* Python / OpenCV (BGR) */
(33, 231, 201)
/* Python / PIL (RGB) */
(201, 231, 33)
/* Java AWT */
new Color(201, 231, 33)
/* .NET */
Color.FromArgb(255, 201, 231, 33)
/* OpenGL / Unity (0–1) */
(0.7882f, 0.9059f, 0.1294f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{201,231,33}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #c9e721 85%, white);
border-color: color-mix(in oklab, #c9e721 40%, transparent);
/* theme-aware in one line */
color: light-dark(#64730C, #EAEED3);
/* relative colour syntax */
--hover: hsl(from #c9e721 h s calc(l - 7));

Design tokens

The same ramp in the four formats a team actually needs. Paste one and the whole palette lands with it.

css custom propertiesclick to select
:root {
  --brand-50: #FBFCF3;
  --brand-100: #F6F9E6;
  --brand-200: #EEF5C6;
  --brand-300: #E6F49A;
  --brand-400: #DAEF67;
  --brand-500: #CEE934;
  --brand-600: #c9e721;
  --brand-700: #9FB814;
  --brand-800: #7F9310;
  --brand-900: #5D6B10;
  --brand-950: #3A430A;
  --brand: #c9e721;
  --brand-ink: #000000;
  --brand-surface: #F9FAF4;
  --brand-border: #E6EDC0;
  --brand-hover: #B2CE16;
  --brand-pressed: #96AE13;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #222414;
    --brand-ink: #EAEED3;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#FBFCF3',
        100: '#F6F9E6',
        200: '#EEF5C6',
        300: '#E6F49A',
        400: '#DAEF67',
        500: '#CEE934',
        600: '#c9e721',
        700: '#9FB814',
        800: '#7F9310',
        900: '#5D6B10',
        950: '#3A430A',
        DEFAULT: '#c9e721',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #FBFCF3,
  '100': #F6F9E6,
  '200': #EEF5C6,
  '300': #E6F49A,
  '400': #DAEF67,
  '500': #CEE934,
  '600': #c9e721,
  '700': #9FB814,
  '800': #7F9310,
  '900': #5D6B10,
  '950': #3A430A,
);
$brand-base: #c9e721;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#FBFCF3", "$type": "color" },
      "100": { "$value": "#F6F9E6", "$type": "color" },
      "200": { "$value": "#EEF5C6", "$type": "color" },
      "300": { "$value": "#E6F49A", "$type": "color" },
      "400": { "$value": "#DAEF67", "$type": "color" },
      "500": { "$value": "#CEE934", "$type": "color" },
      "600": { "$value": "#c9e721", "$type": "color" },
      "700": { "$value": "#9FB814", "$type": "color" },
      "800": { "$value": "#7F9310", "$type": "color" },
      "900": { "$value": "#5D6B10", "$type": "color" },
      "950": { "$value": "#3A430A", "$type": "color" }
    },
    "brandInk": { "$value": "#000000", "$type": "color" }
  }
}

Best text color

Only one of black and white can be right. This is the one, with the number that proves it.

Readable at a glance#000000 on #c9e721 · 14.94:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 1.41:1
AA fail · AA large fail · AAA fail
Aa
Black text · 14.94:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #c9e721 as text scores 1.41:1 on white and 14.94:1 on black.
Best tinted ink on it, if plain black or white feels flat: #64730C at 3.73:1.

Make it accessible

A contrast checker tells you that you failed. This tells you what to ship instead — same hue, same saturation, lightness moved only as far as WCAG demands.

The quick fox
#6B7B0D · 4.70:1
AA on white−25% L
#6B7B0D
The quick fox
#4F5B0A · 7.41:1
AAA on white−32% L
#4F5B0A
The quick fox
#c9e721 · 14.94:1
AA on blackalready passes
#c9e721
The quick fox
#c9e721 · 14.94:1
AAA on blackalready passes
#c9e721

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #879C11 is enough for headings on white. Non-text elements such as icons, chart strokes and focus rings also sit at 3:1 under WCAG 2.2 (1.4.11).

Accessibility — WCAG contrast

Aa
#c9e721 on white: 1.41:1
AA ✗ fail · AA-large · AAA
Aa
#c9e721 on black: 14.94:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #c9e721 as text on that neutral, and that neutral as text on #c9e721.

NeutralRatioBoth directions
White1.41:1AaAa
Slate 501.34:1AaAa
Slate 1001.28:1AaAa
Slate 2001.14:1AaAa
Slate 3001.06:1AaAa
Slate 4001.82:1AaAa
Slate 5003.38:1AaAa
Slate 6005.39:1AaAa
Slate 7007.36:1AaAa
Slate 80010.40:1AaAa
Slate 90012.70:1AaAa
Black14.94:1AaAa
Colour vision deficiency
true color
protanopia · #F7D900
deuteranopia · #F3DA3A
tritanopia · #D6DAC5

Roughly one man in twelve has some form of colour vision deficiency. If any of the three panels above is hard to tell apart from a neighbouring colour in your palette, add a shape, an icon or a label so the meaning does not rest on hue alone.

Color scale — 50 to 950

A Tailwind-shaped ramp built around this exact hex. #c9e721 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.

#FBFCF3
#F6F9E6
#EEF5C6
#E6F49A
#DAEF67
#CEE934
#c9e721
#9FB814
#7F9310
#5D6B10
#3A430A
Base = 600Lightest = 50 · #FBFCF3Darkest = 950 · #3A430AText step on white = 900
Perceptual ramp — OKLCH

The same eleven steps expressed in OKLCH, where equal lightness numbers actually look equally spaced. HSL ramps go muddy in the yellows and washed out in the blues; this one does not. Modern browsers render it natively — the hex ramp above is the fallback.

50100200300400500600700800900950
oklch tokensclick to select
:root {
  --brand-50: oklch(0.97 0.050 119.0);
  --brand-100: oklch(0.94 0.080 119.0);
  --brand-200: oklch(0.88 0.120 119.0);
  --brand-300: oklch(0.80 0.155 119.0);
  --brand-400: oklch(0.72 0.183 119.0);
  --brand-500: oklch(0.64 0.199 119.0);
  --brand-600: oklch(0.56 0.199 119.0);
  --brand-700: oklch(0.48 0.187 119.0);
  --brand-800: oklch(0.40 0.167 119.0);
  --brand-900: oklch(0.32 0.140 119.0);
  --brand-950: oklch(0.24 0.110 119.0);
}

Colors that work with #c9e721

Not a palette — a role sheet. Each swatch answers one question you will hit while building the component.

Text on it#000000
Black wins here
Surface#F9FAF4
Tinted page background
Border#E6EDC0
Hairlines and dividers
Muted text#8F9B4B
Captions on the surface
Accent#1C31EC
Second voice, not a rival
Dark variant#64730C
Hover, pressed, headers
Light variant#F9FDE8
Selected rows, tints
Dark surface#222414
Dark-mode background
Hover#B2CE16
One step down in lightness
Pressed#96AE13
Two steps down
Disabled#C6CBAD
Chroma pulled out
Focus ring#D5F428
Offset from the fill so it reads
Light mode
Everything in its place

Surface, border, heading and body all derive from this one hue, so the screen stays coherent without a second palette.

Primary actionSecondaryBadge
Dark mode
Same hue, inverted

Lightness flips, hue holds. The accent stays the anchor in both themes.

Primary actionSecondaryAccent

In real components

The same eight roles, wired into the interface patterns you will actually build with them. Every state below is a computed value, not a mock-up.

Buttons and states
Save changesHoverPressedDisabled
OutlineSubtleLinkFocused
Form field
you@company.com

Focus ring uses the light variant so the field still reads as one shape.

Send me product updates
Notice
Your export is ready

The file stays available for seven days. Download it before it expires.

NewBetaDraft
Data
Storage used68%
Acme LtdActive
NorthwindTrial
GlobexActive

How to use #c9e721

Derived from its contrast, chroma and lightness — not from taste.

Works well for
  • Text and icons on dark surfaces
  • Primary buttons and calls to action
  • Focus rings, active and selected states
  • Brand accents, badges and data highlights
  • Chart series and data categories
Use with care
  • Text of any size on white — fails WCAG AA
  • Full-page backgrounds — tiring over long sessions
  • Thin strokes and 1px borders — they disappear on light UI
  • Pairing with a same-lightness hue — edges vibrate
Minimum size as text on white
Not as text
Safe as a fill behind white type
No — use #64730C
Safe as a 1px border on white
No — use #879C11

Meaning and mood

What a colour in this family tends to signal, and how this particular chroma and lightness change the reading.

optimisticalertcheap-and-cheerfulvisible

The most visible hue at low light levels, which is why it owns warnings, hazard tape and value retail.

At this chroma the association is amplified — it will dominate anything placed beside it, so give it space and use it sparingly. The mid lightness keeps it versatile in both themes.

Worth knowing

Almost never passes contrast against white. Treat it as a surface or a marker, not as text.

Reads as
  • FormalityLow
  • EnergyHigh
  • Weight48/100
  • TemperatureWarm
  • ApproachabilityHigh

Colour associations are cultural and vary by market. Treat these as a starting point for a conversation with your audience, not a finding about them.

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#3F21E7
Analogous left#E7A221
Analogous right#66E721
Split-complement 1#2166E7
Split-complement 2#A221E7
Triadic 1#21C9E7
Triadic 2#E721C9
Tetradic#21E7A2
On the wheel
Base+30°−30°+120°+240°+180°69°

#c9e721 sits at 69°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red78.8%
Green90.6%
Blue12.9%
R · 0–255
201
0xc9
G · 0–255
231
0xe7
B · 0–255
33
0x21

CMYK percentages

Cyan13.0%
Magenta0.0%
Yellow85.7%
Key (black)9.4%

Total ink coverage is 108%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#c9e721 text on a black background

contrast 14.94:1

Card sample

#c9e721 text on a white background

contrast 1.41:1

Card sample

#c9e721 on grey

1.28:1

#c9e721 on its own surface

1.34:1

#c9e721 on its dark surface

11.23:1

CSS3 live lab

Text font color

The quick brown fox

color: #c9e721;
Background color
Panel with #c9e721 background
background-color: #c9e721;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #c9e721;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(201, 231, 33, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(201, 231, 33, 0.45);
Border & gradient
Gradient panel
border: 3px solid #c9e721;
background: linear-gradient(135deg, #c9e721, #45E721);
Gradient text

Gradient headline

background: linear-gradient(90deg, #c9e721, #21E72F);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #c9e721;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #c9e721;
caret-color: #c9e721;
Left rule
Pull quote or callout
border-left: 4px solid #c9e721;
Ring + tint
Selected chip
background: #F9FDE8;
box-shadow: inset 0 0 0 2px #c9e721;
Conic badge
68%
background: conic-gradient(#c9e721 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #c9e721 over white; the bottom row is the same alpha over a checkerboard, so you can see what survives on a photo or a video.

Bottom row of hexes is the flattened result over white — use those when a design tool refuses transparency, or when you need a solid fallback.

alpha in every syntaxclick to select
rgba(201, 231, 33, 0.5)
rgb(201 231 33 / 50%)
#c9e72180
hsl(69 81% 52% / 50%)
color-mix(in srgb, #c9e721 50%, transparent)
Alpha8-digit hexFlat on white
10%#c9e7211a#FAFDE9
20%#c9e72133#F4FAD3
40%#c9e72166#E9F5A6
60%#c9e72199#DFF17A
80%#c9e721cc#D4EC4D

Gradients from #c9e721

Six recipes, each built from this hex and shown with the exact CSS that produced it.

Elevation
Same hue, three lightnesses — safe anywhere
background: linear-gradient(135deg, #D6ED58, #c9e721 45%, #64730C);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #c9e721, #29D317);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #c9e721, #3F21E7);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #DDF074 0%, #c9e721 45%, #64730C 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F9FAF4, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #ECA84F 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #6BEA3D 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #64730C 0%, transparent 65%), #c9e721;

Monochromatic scale

Palettes built from #c9e721

Shades — darker

Tints — lighter

Tones — desaturated

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.

#c9e721 in the real world

Where a color in this family tends to land, and the interface roles it is usually asked to play.

Industries
RetailLeisureEnergyWarning systems
Common UI roles
ButtonsLinksFocus statesCharts
Print note

Sits outside most CMYK gamuts — expect a duller press result, or specify a spot ink.

On screens

Holds up across typical panel gamma. Still worth checking on an uncalibrated laptop, where mid-tones shift most.

In dark mode

Usable as-is on a dark surface at 14.94:1.

Explore nearby colors

Small, deliberate steps away from this hex — useful when you are hunting for the version of a colour that finally feels right.

#c9e721, answered

What color is #c9e721?

#c9e721 is a balanced electric yellow, closest to Green Yellow (ΔE2000 8.3). It sits at 69° on the hue wheel with 81% saturation and 52% lightness, which reads as warm.

What is the RGB value of #c9e721?

rgb(201, 231, 33) — 201 red, 231 green and 33 blue out of 255, or 78.8% / 90.6% / 12.9% by channel.

What is #c9e721 in HSL and HSV?

hsl(69, 81%, 52%) and hsv(69, 86%, 91%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #c9e721 a light or a dark color?

It is a light color. Relative luminance is 0.6968 and perceived brightness is 82%, so black text on it reaches 14.94:1.

Should I use black or white text on #c9e721?

Black. It scores 14.94:1 against #c9e721, versus 1.41:1 for white — AAA at any size.

Is #c9e721 accessible on a white background?

#c9e721 on white scores 1.41:1, which fails WCAG AA at every size. Darken it to #6B7B0D to reach 4.5:1, or #4F5B0A for 7:1.

What is the complementary color of #c9e721?

#3F21E7 sits directly opposite on the wheel. Softer options are the split-complements #2166E7 and #A221E7, which give the same contrast with far less vibration.

What colors go well with #c9e721?

For interface work: #F9FAF4 as the surface, #E6EDC0 for borders, #8F9B4B for secondary text, #1C31EC as an accent and #64730C for hover and pressed states. For a palette, the analogous pair #E7A221 and #66E721 stays calm, while #3F21E7 is the loudest partner.

What is #c9e721 in CMYK for printing?

cmyk(13%, 0%, 86%, 9%). This is a screen-to-ink approximation — a color this saturated sits outside most CMYK gamuts and will print duller than it looks here.

Is #c9e721 warm or cool?

Warm — it scores 33 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #E7BC21; nudged cooler, #80E91F.

Which Tailwind color is closest to #c9e721?

The lime family — its 500 step is #84cc16, ΔE2000 11.1 away. That is a visible difference, so define #c9e721 as a custom token rather than reaching for the built-in.

How do I use #c9e721 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#c9e721] or text-[#c9e721], or register the whole ramp under theme.extend.colors.brand so you get bg-brand-500 and friends. The generated 50–950 scale on this page is ready to paste into your config.

What is #c9e721 with 50% opacity?

rgba(201, 231, 33, 0.5), or #c9e72180 in eight-digit hex. Over white that composites to #E4F390; over black, #657411.

Is #c9e721 a web-safe color?

No. The nearest web-safe colour is #CCFF33, ΔE2000 5.5 away. The palette only matters for legacy displays and some email clients now.

What does the color #c9e721 mean?

As a yellow, it reads optimistic, alert, cheap-and-cheerful. The most visible hue at low light levels, which is why it owns warnings, hazard tape and value retail. At this chroma the effect is amplified — it will dominate whatever sits beside it.

What gradient works with #c9e721?

The safest is same-hue elevation: linear-gradient(135deg, #D6ED58, #c9e721 45%, #64730C). For more colour, a short hue run to #29D317 keeps it rich without turning muddy.

Work with #c9e721 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #c9e721 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.