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yellow · warm

#effc13

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

Token name suggestion: Atlas Citron

RGB
239, 252, 19
HSL
63°, 98%, 53%
CMYK
5, 0, 93, 1
Luminance
0.8802

#effc13 is a balanced electric yellow, 63° on the wheel and 28/100 on the cool side. Put black text on it (18.60:1). As text it scores 1.13:1 on white — use #737902 instead. Nearest name is Yellow, nearest Tailwind family is lime.

hsl(63 98% 53%)rgb(239 252 19)Base step 500AAA inkWarm

At a glance

Every number on this page in one read: what #effc13 is made of, how bright it looks, and which way it leans.

Hex
#effc13
Hue
63°
yellow
Saturation
98%
electric
Lightness
53%
balanced
Brightness
99%
HSV value
Perceived
91%
weighted brightness
Luminance
0.8802
WCAG relative
Temperature
Warm
28/100 cool
Color family
Yellow
Tone
Electric
Best ink
Black
18.60:1
Closest name
Yellow
ΔE2000 2.9
Chroma
94.8
LCH, 0–130ish
OKLCH L
0.949
perceptual lightness
Tailwind
lime
500 · ΔE 17.6
Web-safe
#FFFF00
nearest of 216
Where it sits
Hue63° of 360°
Saturation98%
Lightness53%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #effc13.

Temperature
Warm ← → Cool28% 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
Red21%
Green79%
Blue0%

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

Every format

HEX#effc13
HEX (8-digit)#effc13ff
RGBrgb(239, 252, 19)
RGBArgba(239, 252, 19, 1)
HSLhsl(63, 98%, 53%)
HSV / HSBhsv(63, 92%, 99%)
HWBhwb(63 7% 1%)
CMYKcmyk(5%, 0%, 93%, 1%)
LABlab(95.2 -26.5 91.0)
LCHlch(95.2 94.8 106.2)
OKLCHoklch(0.949 0.210 113.5)
XYZ (D65)xyz(70.53, 88.02, 13.89)
Decimal15727635
Display P3color(display-p3 0.937 0.988 0.075)
Web-safe#FFFF00

Copy-ready code

every platformclick to select
/* CSS */
color: #effc13;
background-color: #effc13;
/* CSS custom property */
--brand: #effc13;
/* Tailwind (arbitrary) */
class="text-[#effc13] bg-[#effc13]"
/* SCSS */
$brand: #effc13;
/* SwiftUI */
Color(red: 0.937, green: 0.988, blue: 0.075)
/* UIKit */
UIColor(red: 0.937, green: 0.988, blue: 0.075, alpha: 1)
/* Android XML */
<color name="brand">#EFFC13</color>
/* Android Compose */
Color(0xFFEFFC13)
/* Flutter */
Color(0xFFEFFC13)
/* Python / OpenCV (BGR) */
(19, 252, 239)
/* Python / PIL (RGB) */
(239, 252, 19)
/* Java AWT */
new Color(239, 252, 19)
/* .NET */
Color.FromArgb(255, 239, 252, 19)
/* OpenGL / Unity (0–1) */
(0.9373f, 0.9882f, 0.0745f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{239,252,19}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #effc13 85%, white);
border-color: color-mix(in oklab, #effc13 40%, transparent);
/* theme-aware in one line */
color: light-dark(#777E02, #EDEED3);
/* relative colour syntax */
--hover: hsl(from #effc13 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: #FDFDF1;
  --brand-100: #FBFCE4;
  --brand-200: #F8FBC1;
  --brand-300: #F8FE90;
  --brand-400: #F4FD59;
  --brand-500: #effc13;
  --brand-600: #E5F203;
  --brand-700: #BFC903;
  --brand-800: #98A102;
  --brand-900: #6E7406;
  --brand-950: #454904;
  --brand: #effc13;
  --brand-ink: #000000;
  --brand-surface: #FAFAF4;
  --brand-border: #EAEDC0;
  --brand-hover: #DCE803;
  --brand-pressed: #BAC502;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #242414;
    --brand-ink: #EDEED3;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#FDFDF1',
        100: '#FBFCE4',
        200: '#F8FBC1',
        300: '#F8FE90',
        400: '#F4FD59',
        500: '#effc13',
        600: '#E5F203',
        700: '#BFC903',
        800: '#98A102',
        900: '#6E7406',
        950: '#454904',
        DEFAULT: '#effc13',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #FDFDF1,
  '100': #FBFCE4,
  '200': #F8FBC1,
  '300': #F8FE90,
  '400': #F4FD59,
  '500': #effc13,
  '600': #E5F203,
  '700': #BFC903,
  '800': #98A102,
  '900': #6E7406,
  '950': #454904,
);
$brand-base: #effc13;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#FDFDF1", "$type": "color" },
      "100": { "$value": "#FBFCE4", "$type": "color" },
      "200": { "$value": "#F8FBC1", "$type": "color" },
      "300": { "$value": "#F8FE90", "$type": "color" },
      "400": { "$value": "#F4FD59", "$type": "color" },
      "500": { "$value": "#effc13", "$type": "color" },
      "600": { "$value": "#E5F203", "$type": "color" },
      "700": { "$value": "#BFC903", "$type": "color" },
      "800": { "$value": "#98A102", "$type": "color" },
      "900": { "$value": "#6E7406", "$type": "color" },
      "950": { "$value": "#454904", "$type": "color" }
    },
    "brandInk": { "$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 #effc13 · 18.60:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 1.13:1
AA fail · AA large fail · AAA fail
Aa
Black text · 18.60:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #effc13 as text scores 1.13:1 on white and 18.60:1 on black.
Best tinted ink on it, if plain black or white feels flat: #777E02 at 3.90:1.

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
#737902 · 4.70:1
AA on white−29% L
#737902
The quick fox
#565B01 · 7.26:1
AAA on white−35% L
#565B01
The quick fox
#effc13 · 18.60:1
AA on blackalready passes
#effc13
The quick fox
#effc13 · 18.60:1
AAA on blackalready passes
#effc13

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #8F9802 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
#effc13 on white: 1.13:1
AA ✗ fail · AA-large · AAA
Aa
#effc13 on black: 18.60:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #effc13 as text on that neutral, and that neutral as text on #effc13.

NeutralRatioBoth directions
White1.13:1AaAa
Slate 501.08:1AaAa
Slate 1001.03:1AaAa
Slate 2001.09:1AaAa
Slate 3001.32:1AaAa
Slate 4002.27:1AaAa
Slate 5004.22:1AaAa
Slate 6006.71:1AaAa
Slate 7009.17:1AaAa
Slate 80012.96:1AaAa
Slate 90015.82:1AaAa
Black18.60:1AaAa
Colour vision deficiency
true color
protanopia · #FFEF00
deuteranopia · #FFF337
tritanopia · #FFECD7

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. #effc13 is pinned to step 500; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#FDFDF1
#FBFCE4
#F8FBC1
#F8FE90
#F4FD59
#effc13
#E5F203
#BFC903
#98A102
#6E7406
#454904
Base = 500Lightest = 50 · #FDFDF1Darkest = 950 · #454904Text 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 0.053 113.5);
  --brand-100: oklch(0.94 0.084 113.5);
  --brand-200: oklch(0.88 0.126 113.5);
  --brand-300: oklch(0.80 0.164 113.5);
  --brand-400: oklch(0.72 0.193 113.5);
  --brand-500: oklch(0.64 0.210 113.5);
  --brand-600: oklch(0.56 0.210 113.5);
  --brand-700: oklch(0.48 0.198 113.5);
  --brand-800: oklch(0.40 0.177 113.5);
  --brand-900: oklch(0.32 0.147 113.5);
  --brand-950: oklch(0.24 0.116 113.5);
}

Colors that work with #effc13

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#FAFAF4
Tinted page background
Border#EAEDC0
Hairlines and dividers
Muted text#969B4B
Captions on the surface
Accent#103EFF
Second voice, not a rival
Dark variant#777E02
Hover, pressed, headers
Light variant#FDFFE6
Selected rows, tints
Dark surface#242414
Dark-mode background
Hover#DCE803
One step down in lightness
Pressed#BAC502
Two steps down
Disabled#CCCDB2
Chroma pulled out
Focus ring#F3FF24
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 #effc13

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 #777E02
Safe as a 1px border on white
No — use #8F9802

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
  • Weight47/100
  • 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#2013FC
Analogous left#FC9413
Analogous right#7BFC13
Split-complement 1#137BFC
Split-complement 2#9413FC
Triadic 1#13EFFC
Triadic 2#FC13EF
Tetradic#13FC94
On the wheel
Base+30°−30°+120°+240°+180°63°

#effc13 sits at 63°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red93.7%
Green98.8%
Blue7.5%
R · 0–255
239
0xef
G · 0–255
252
0xfc
B · 0–255
19
0x13

CMYK percentages

Cyan5.2%
Magenta0.0%
Yellow92.5%
Key (black)1.2%

Total ink coverage is 99%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#effc13 text on a black background

contrast 18.60:1

Card sample

#effc13 text on a white background

contrast 1.13:1

Card sample

#effc13 on grey

1.03:1

#effc13 on its own surface

1.08:1

#effc13 on its dark surface

13.91:1

CSS3 live lab

Text font color

The quick brown fox

color: #effc13;
Background color
Panel with #effc13 background
background-color: #effc13;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #effc13;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(239, 252, 19, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(239, 252, 19, 0.45);
Border & gradient
Gradient panel
border: 3px solid #effc13;
background: linear-gradient(135deg, #effc13, #54FC13);
Gradient text

Gradient headline

background: linear-gradient(90deg, #effc13, #19FC13);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #effc13;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #effc13;
caret-color: #effc13;
Left rule
Pull quote or callout
border-left: 4px solid #effc13;
Ring + tint
Selected chip
background: #FDFFE6;
box-shadow: inset 0 0 0 2px #effc13;
Conic badge
68%
background: conic-gradient(#effc13 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #effc13 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(239, 252, 19, 0.5)
rgb(239 252 19 / 50%)
#effc1380
hsl(63 98% 53% / 50%)
color-mix(in srgb, #effc13 50%, transparent)
Alpha8-digit hexFlat on white
10%#effc131a#FDFFE7
20%#effc1333#FCFED0
40%#effc1366#F9FEA1
60%#effc1399#F5FD71
80%#effc13cc#F2FD42

Gradients from #effc13

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, #F3FD4F, #effc13 45%, #777E02);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #effc13, #31ED03);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #effc13, #2013FC);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #F5FD6D 0%, #effc13 45%, #777E02 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #FAFAF4, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #FD9C45 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #7BFC31 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #777E02 0%, transparent 65%), #effc13;

Monochromatic scale

Palettes built from #effc13

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.

#effc13 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

Very light values are indistinguishable from white on a dim phone screen outdoors. Give it a border if the boundary matters.

In dark mode

Usable as-is on a dark surface at 18.60:1.

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.

#effc13, answered

What color is #effc13?

#effc13 is a balanced electric yellow, closest to Yellow (ΔE2000 2.9). It sits at 63° on the hue wheel with 98% saturation and 53% lightness, which reads as warm.

What is the RGB value of #effc13?

rgb(239, 252, 19) — 239 red, 252 green and 19 blue out of 255, or 93.7% / 98.8% / 7.5% by channel.

What is #effc13 in HSL and HSV?

hsl(63, 98%, 53%) and hsv(63, 92%, 99%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #effc13 a light or a dark color?

It is a light color. Relative luminance is 0.8802 and perceived brightness is 91%, so black text on it reaches 18.60:1.

Should I use black or white text on #effc13?

Black. It scores 18.60:1 against #effc13, versus 1.13:1 for white — AAA at any size.

Is #effc13 accessible on a white background?

#effc13 on white scores 1.13:1, which fails WCAG AA at every size. Darken it to #737902 to reach 4.5:1, or #565B01 for 7:1.

What is the complementary color of #effc13?

#2013FC sits directly opposite on the wheel. Softer options are the split-complements #137BFC and #9413FC, which give the same contrast with far less vibration.

What colors go well with #effc13?

For interface work: #FAFAF4 as the surface, #EAEDC0 for borders, #969B4B for secondary text, #103EFF as an accent and #777E02 for hover and pressed states. For a palette, the analogous pair #FC9413 and #7BFC13 stays calm, while #2013FC is the loudest partner.

What is #effc13 in CMYK for printing?

cmyk(5%, 0%, 93%, 1%). 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 #effc13 warm or cool?

Warm — it scores 28 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #FCBE13; nudged cooler, #9AFE10.

Which Tailwind color is closest to #effc13?

The lime family — its 500 step is #84cc16, ΔE2000 17.6 away. That is a visible difference, so define #effc13 as a custom token rather than reaching for the built-in.

How do I use #effc13 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#effc13] or text-[#effc13], 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 #effc13 with 50% opacity?

rgba(239, 252, 19, 0.5), or #effc1380 in eight-digit hex. Over white that composites to #F7FE89; over black, #787E0A.

Is #effc13 a web-safe color?

No. The nearest web-safe colour is #FFFF00, ΔE2000 2.9 away. The palette only matters for legacy displays and some email clients now.

What does the color #effc13 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 #effc13?

The safest is same-hue elevation: linear-gradient(135deg, #F3FD4F, #effc13 45%, #777E02). For more colour, a short hue run to #31ED03 keeps it rich without turning muddy.

Work with #effc13 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #effc13 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.