Skip to content
green · cool

#3fe366

a balanced, vivid green · cool · closest name: Spring Green

Token name suggestion: Signal Basil

RGB
63, 227, 102
HSL
134°, 75%, 57%
CMYK
72, 0, 55, 11
Luminance
0.5695

#3fe366 is a balanced vivid green, 134° on the wheel and 68/100 on the cool side. Put black text on it (12.39:1). As text it scores 1.69:1 on white — use #148930 instead. Nearest name is Spring Green, nearest Tailwind family is green.

hsl(134 75% 57%)rgb(63 227 102)Base step 500AAA inkCool

At a glance

Every number on this page in one read: what #3fe366 is made of, how bright it looks, and which way it leans.

Hex
#3fe366
Hue
134°
green
Saturation
75%
vivid
Lightness
57%
balanced
Brightness
89%
HSV value
Perceived
71%
weighted brightness
Luminance
0.5695
WCAG relative
Temperature
Cool
68/100 cool
Color family
Green
Tone
Vivid
Best ink
Black
12.39:1
Closest name
Spring Green
ΔE2000 6.2
Chroma
82.7
LCH, 0–130ish
OKLCH L
0.807
perceptual lightness
Tailwind
green
500 · ΔE 7.6
Web-safe
#33CC66
nearest of 216
Where it sits
Hue134° of 360°
Saturation75%
Lightness57%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #3fe366.

Temperature
Warm ← → Cool68% cool

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

Luminance by channel
Red2%
Green96%
Blue2%

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

Every format

HEX#3fe366
HEX (8-digit)#3fe366ff
RGBrgb(63, 227, 102)
RGBArgba(63, 227, 102, 1)
HSLhsl(134, 75%, 57%)
HSV / HSBhsv(134, 72%, 89%)
HWBhwb(134 25% 11%)
CMYKcmyk(72%, 0%, 55%, 11%)
LABlab(80.2 -66.9 48.6)
LCHlch(80.2 82.7 144.0)
OKLCHoklch(0.807 0.214 147.2)
XYZ (D65)xyz(31.91, 56.95, 21.88)
Decimal4186982
Display P3color(display-p3 0.247 0.890 0.400)
Web-safe#33CC66

Copy-ready code

every platformclick to select
/* CSS */
color: #3fe366;
background-color: #3fe366;
/* CSS custom property */
--brand: #3fe366;
/* Tailwind (arbitrary) */
class="text-[#3fe366] bg-[#3fe366]"
/* SCSS */
$brand: #3fe366;
/* SwiftUI */
Color(red: 0.247, green: 0.890, blue: 0.400)
/* UIKit */
UIColor(red: 0.247, green: 0.890, blue: 0.400, alpha: 1)
/* Android XML */
<color name="brand">#3FE366</color>
/* Android Compose */
Color(0xFF3FE366)
/* Flutter */
Color(0xFF3FE366)
/* Python / OpenCV (BGR) */
(102, 227, 63)
/* Python / PIL (RGB) */
(63, 227, 102)
/* Java AWT */
new Color(63, 227, 102)
/* .NET */
Color.FromArgb(255, 63, 227, 102)
/* OpenGL / Unity (0–1) */
(0.2471f, 0.8902f, 0.4000f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{63,227,102}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #3fe366 85%, white);
border-color: color-mix(in oklab, #3fe366 40%, transparent);
/* theme-aware in one line */
color: light-dark(#106F27, #D3EED9);
/* relative colour syntax */
--hover: hsl(from #3fe366 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: #F3FCF5;
  --brand-100: #E7F9EB;
  --brand-200: #C8F4D2;
  --brand-300: #9DF1B1;
  --brand-400: #6CEA8A;
  --brand-500: #3fe366;
  --brand-600: #1FD64B;
  --brand-700: #1AB23E;
  --brand-800: #158E32;
  --brand-900: #136727;
  --brand-950: #0C4019;
  --brand: #3fe366;
  --brand-ink: #000000;
  --brand-surface: #F4FAF6;
  --brand-border: #C0EDCA;
  --brand-hover: #20DE4E;
  --brand-pressed: #1CBF43;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #142418;
    --brand-ink: #D3EED9;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F3FCF5',
        100: '#E7F9EB',
        200: '#C8F4D2',
        300: '#9DF1B1',
        400: '#6CEA8A',
        500: '#3fe366',
        600: '#1FD64B',
        700: '#1AB23E',
        800: '#158E32',
        900: '#136727',
        950: '#0C4019',
        DEFAULT: '#3fe366',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F3FCF5,
  '100': #E7F9EB,
  '200': #C8F4D2,
  '300': #9DF1B1,
  '400': #6CEA8A,
  '500': #3fe366,
  '600': #1FD64B,
  '700': #1AB23E,
  '800': #158E32,
  '900': #136727,
  '950': #0C4019,
);
$brand-base: #3fe366;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F3FCF5", "$type": "color" },
      "100": { "$value": "#E7F9EB", "$type": "color" },
      "200": { "$value": "#C8F4D2", "$type": "color" },
      "300": { "$value": "#9DF1B1", "$type": "color" },
      "400": { "$value": "#6CEA8A", "$type": "color" },
      "500": { "$value": "#3fe366", "$type": "color" },
      "600": { "$value": "#1FD64B", "$type": "color" },
      "700": { "$value": "#1AB23E", "$type": "color" },
      "800": { "$value": "#158E32", "$type": "color" },
      "900": { "$value": "#136727", "$type": "color" },
      "950": { "$value": "#0C4019", "$type": "color" }
    },
    "brandInk": { "$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 #3fe366 · 12.39:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 1.69:1
AA fail · AA large fail · AAA fail
Aa
Black text · 12.39:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #3fe366 as text scores 1.69:1 on white and 12.39:1 on black.
Best tinted ink on it, if plain black or white feels flat: #106F27 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
#148930 · 4.52:1
AA on white−26% L
#148930
The quick fox
#0F6624 · 7.13:1
AAA on white−34% L
#0F6624
The quick fox
#3fe366 · 12.39:1
AA on blackalready passes
#3fe366
The quick fox
#3fe366 · 12.39:1
AAA on blackalready passes
#3fe366

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #19A93B 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
#3fe366 on white: 1.69:1
AA ✗ fail · AA-large · AAA
Aa
#3fe366 on black: 12.39:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #3fe366 as text on that neutral, and that neutral as text on #3fe366.

NeutralRatioBoth directions
White1.69:1AaAa
Slate 501.62:1AaAa
Slate 1001.55:1AaAa
Slate 2001.37:1AaAa
Slate 3001.14:1AaAa
Slate 4001.51:1AaAa
Slate 5002.81:1AaAa
Slate 6004.47:1AaAa
Slate 7006.11:1AaAa
Slate 8008.63:1AaAa
Slate 90010.53:1AaAa
Black12.39:1AaAa
Colour vision deficiency
true color
protanopia · #E6CF5A
deuteranopia · #D3C270
tritanopia · #00DEC7

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. #3fe366 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.

#F3FCF5
#E7F9EB
#C8F4D2
#9DF1B1
#6CEA8A
#3fe366
#1FD64B
#1AB23E
#158E32
#136727
#0C4019
Base = 500Lightest = 50 · #F3FCF5Darkest = 950 · #0C4019Text 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 0.054 147.2);
  --brand-100: oklch(0.94 0.086 147.2);
  --brand-200: oklch(0.88 0.129 147.2);
  --brand-300: oklch(0.80 0.167 147.2);
  --brand-400: oklch(0.72 0.197 147.2);
  --brand-500: oklch(0.64 0.214 147.2);
  --brand-600: oklch(0.56 0.214 147.2);
  --brand-700: oklch(0.48 0.202 147.2);
  --brand-800: oklch(0.40 0.180 147.2);
  --brand-900: oklch(0.32 0.150 147.2);
  --brand-950: oklch(0.24 0.118 147.2);
}

Colors that work with #3fe366

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#F4FAF6
Tinted page background
Border#C0EDCA
Hairlines and dividers
Muted text#4B9B5E
Captions on the surface
Accent#E53BE7
Second voice, not a rival
Dark variant#106F27
Hover, pressed, headers
Light variant#E9FCED
Selected rows, tints
Dark surface#142418
Dark-mode background
Hover#20DE4E
One step down in lightness
Pressed#1CBF43
Two steps down
Disabled#BDD5C3
Chroma pulled out
Focus ring#47F06F
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 #3fe366

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
  • Status meaning — pair it with an icon or label, never colour alone
  • 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 #106F27
Safe as a 1px border on white
No — use #19A93B

Meaning and mood

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

safegrowingnaturalpermissive

Green means go, well, and grown. It carries finance, sustainability and health with almost no explanation needed.

This is a confident chroma: strong enough to lead a brand, restrained enough to live in an interface all day. The mid lightness keeps it versatile in both themes.

Worth knowing

Red/green pairs are the most common colour-blindness failure — never let the two carry meaning alone.

Reads as
  • FormalityMedium
  • EnergyMedium-high
  • Weight43/100
  • TemperatureCool
  • ApproachabilityReserved

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#E33FBC
Analogous left#6AE33F
Analogous right#3FE3B8
Split-complement 1#B83FE3
Split-complement 2#E33F6A
Triadic 1#663FE3
Triadic 2#E3663F
Tetradic#3F6AE3
On the wheel
Base+30°−30°+120°+240°+180°134°

#3fe366 sits at 134°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red24.7%
Green89.0%
Blue40.0%
R · 0–255
63
0x3f
G · 0–255
227
0xe3
B · 0–255
102
0x66

CMYK percentages

Cyan72.2%
Magenta0.0%
Yellow55.1%
Key (black)11.0%

Total ink coverage is 138%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#3fe366 text on a black background

contrast 12.39:1

Card sample

#3fe366 text on a white background

contrast 1.69:1

Card sample

#3fe366 on grey

1.55:1

#3fe366 on its own surface

1.60:1

#3fe366 on its dark surface

9.57:1

CSS3 live lab

Text font color

The quick brown fox

color: #3fe366;
Background color
Panel with #3fe366 background
background-color: #3fe366;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #3fe366;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(63, 227, 102, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(63, 227, 102, 0.45);
Border & gradient
Gradient panel
border: 3px solid #3fe366;
background: linear-gradient(135deg, #3fe366, #3FE3D3);
Gradient text

Gradient headline

background: linear-gradient(90deg, #3fe366, #3FCAE3);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #3fe366;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #3fe366;
caret-color: #3fe366;
Left rule
Pull quote or callout
border-left: 4px solid #3fe366;
Ring + tint
Selected chip
background: #E9FCED;
box-shadow: inset 0 0 0 2px #3fe366;
Conic badge
68%
background: conic-gradient(#3fe366 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #3fe366 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(63, 227, 102, 0.5)
rgb(63 227 102 / 50%)
#3fe36680
hsl(134 75% 57% / 50%)
color-mix(in srgb, #3fe366 50%, transparent)
Alpha8-digit hexFlat on white
10%#3fe3661a#ECFCF0
20%#3fe36633#D9F9E0
40%#3fe36666#B2F4C2
60%#3fe36699#8CEEA3
80%#3fe366cc#65E985

Gradients from #3fe366

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, #75EB91, #3fe366 45%, #106F27);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #3fe366, #25DFDD);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #3fe366, #E33FBC);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #8FEFA6 0%, #3fe366 45%, #106F27 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4FAF6, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #97E96C 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #5AE7CE 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #106F27 0%, transparent 65%), #3fe366;

Monochromatic scale

Palettes built from #3fe366

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.

#3fe366 in the real world

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

Industries
SustainabilityFinanceHealth and wellnessAgriculture
Common UI roles
ButtonsLinksFocus statesCharts
Print note

Converts to four-color process without much drama. Proof it anyway.

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 12.39:1.

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.

#3fe366, answered

What color is #3fe366?

#3fe366 is a balanced vivid green, closest to Spring Green (ΔE2000 6.2). It sits at 134° on the hue wheel with 75% saturation and 57% lightness, which reads as cool.

What is the RGB value of #3fe366?

rgb(63, 227, 102) — 63 red, 227 green and 102 blue out of 255, or 24.7% / 89% / 40% by channel.

What is #3fe366 in HSL and HSV?

hsl(134, 75%, 57%) and hsv(134, 72%, 89%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #3fe366 a light or a dark color?

It is a light color. Relative luminance is 0.5695 and perceived brightness is 71%, so black text on it reaches 12.39:1.

Should I use black or white text on #3fe366?

Black. It scores 12.39:1 against #3fe366, versus 1.69:1 for white — AAA at any size.

Is #3fe366 accessible on a white background?

#3fe366 on white scores 1.69:1, which fails WCAG AA at every size. Darken it to #148930 to reach 4.5:1, or #0F6624 for 7:1.

What is the complementary color of #3fe366?

#E33FBC sits directly opposite on the wheel. Softer options are the split-complements #B83FE3 and #E33F6A, which give the same contrast with far less vibration.

What colors go well with #3fe366?

For interface work: #F4FAF6 as the surface, #C0EDCA for borders, #4B9B5E for secondary text, #E53BE7 as an accent and #106F27 for hover and pressed states. For a palette, the analogous pair #6AE33F and #3FE3B8 stays calm, while #E33FBC is the loudest partner.

What is #3fe366 in CMYK for printing?

cmyk(72%, 0%, 55%, 11%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #3fe366 warm or cool?

Cool — it scores 68 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #54E33F; nudged cooler, #3DE5A3.

Which Tailwind color is closest to #3fe366?

The green family — its 500 step is #22c55e, ΔE2000 7.6 away. That is a visible difference, so define #3fe366 as a custom token rather than reaching for the built-in.

How do I use #3fe366 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#3fe366] or text-[#3fe366], 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 #3fe366 with 50% opacity?

rgba(63, 227, 102, 0.5), or #3fe36680 in eight-digit hex. Over white that composites to #9FF1B3; over black, #207233.

Is #3fe366 a web-safe color?

No. The nearest web-safe colour is #33CC66, ΔE2000 5.9 away. The palette only matters for legacy displays and some email clients now.

What does the color #3fe366 mean?

As a green, it reads safe, growing, natural. Green means go, well, and grown. It carries finance, sustainability and health with almost no explanation needed. At this chroma the effect is amplified — it will dominate whatever sits beside it.

What gradient works with #3fe366?

The safest is same-hue elevation: linear-gradient(135deg, #75EB91, #3fe366 45%, #106F27). For more colour, a short hue run to #25DFDD keeps it rich without turning muddy.

Work with #3fe366 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #3fe366 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.