#51B366 Color

#51B366 is rgb(81, 179, 102) in RGB, hsl(133, 39%, 51%) in HSL, and about cmyk(55%, 0%, 43%, 30%) in CMYK. It has no registered color name of its own — the closest is Medium Sea Green (#3CB371), clearly related but distinguishable side by side at ΔE 7.25. Black text is the more readable choice on this background.

#51B366

HEX#51B366

RGBrgb(81, 179, 102)

HSLhsl(133, 39%, 51%)

HSVhsv(133, 55%, 70%)

CMYKcmyk(55%, 0%, 43%, 30%)

OKLCHoklch(68.9% 0.145 148.4)

LABlab(65.71% -42.79 30.21)

LCHlch(65.71% 52.39 144.78)

What #51B366 Is Called

Most hex codes have no name: there are 16.7 million of them and a few thousand registered names. These are the named colors nearest to #51B366, ordered by CIE76 distance in CIELAB. Anything under about ΔE 2 is a difference most people cannot see.

Medium Sea Green#3CB371ΔE 7.25 Emerald#50C878ΔE 8.82 GO Green#00AB66ΔE 10.84 Mantis#74C365ΔE 11.49 Green (Pigment)#00A550ΔE 11.79 Green Frog#00A86BΔE 12.54

Browse the full index of named colors A-Z or every green in the library.

#51B366 Channel Values

How #51B366 breaks down in each color model. Hue is measured in degrees around the color wheel; saturation, lightness, and the CMYK inks are percentages.

Model	Channels	Notes
RGB	R 81 · G 179 · B 102	8-bit channels as sent to the display
HSL	H 133° · S 39% · L 51%	Easiest model for building lighter and darker variants
HSV	H 133° · S 55% · V 70%	Matches the picker in most design tools
CMYK	C 55% · M 0% · Y 43% · K 30%	Approximate ink mix; confirm with an ICC profile before printing
Luminance	2.63:1 vs white · 7.99:1 vs black	WCAG 2.2 relative-luminance contrast ratios

Text Contrast & Accessibility

WCAG 2.2 contrast ratios for text on a #51B366 background. AA requires 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1. Contrast is one check, not a full accessibility review.

Fails AAWhite text2.63:1AA normal AA large AAA normal

TextBlack text7.99:1AA normal AA large AAA normal

Need a specific ratio against another background? Open #51B366 in the contrast checker.

Colors That Go With #51B366

Pairings derived from color-wheel relationships. The complementary color sits opposite #51B366; analogous colors sit beside it; triadic and split-complementary sets spread evenly around the wheel. Select any swatch for its own breakdown.

Base

Complementary

Analogous

Analogous

Triadic

Triadic

Split comp.

Split comp.

Tints & Shades of #51B366

Lighter tints and darker shades built by moving the lightness channel while holding hue and saturation, which is what you want for hover states, backgrounds, and text variants.

Tints

Shades

Want a full 50-950 ramp with semantic roles? Generate design tokens from #51B366.

How #51B366 Looks with Color Vision Deficiency

Simulated with the Viénot, Brettel & Mollon LMS projection model. Anomalous types are rendered as partial versions of the matching dichromacy, which is an approximation rather than a per-person clinical model.

Typical#51B366

Protanopia#A7A767

Protanomaly#8DAC66

Deuteranopia#9B9B6A

Deuteranomaly#84A568

Tritanopia#62ACAC

Tritanomaly#5CAF95

Achromatopsia#A0A0A0

Test a full palette in the color blindness simulator.

Using #51B366 in Code

Copy-ready declarations for the places this color usually ends up.

CSS custom property--color-51b366: #51B366;

CSS backgroundbackground-color: #51B366;

Tailwind configcolors: { 'color-51b366': '#51B366' }

SwiftUIColor(red: 0.318, green: 0.702, blue: 0.400)

Android XML<color name="color_51b366">#51B366</color>

SVG fillfill="#51B366"

More Green Colors

#51B366 sits in the green family. These are its neighbours across that family's full range, each with its own breakdown.

000200 fdfff5 001f00 f7fee7 002400 f7fbf5 002c22 f5fffa 002e00 f5fff5 003300 f0fff0 008000 00db87 0d542b 20483f 33cc66 46c399 5ea500 728639 91e0b7 a3f5d8 bcd7bc d1ffed

#51B366 Frequently Asked Questions

What color is #51B366?

#51B366 is a mid-tone green — rgb(81, 179, 102) in RGB and hsl(133, 39%, 51%) in HSL. It carries no registered color name of its own; the closest named color is Medium Sea Green (#3CB371), which is clearly related but distinguishable side by side at a CIE76 distance of 7.25.

What is the RGB value of #51B366?

#51B366 is rgb(81, 179, 102) — red 81, green 179, and blue 102 on the 0-255 scale.

What is the CMYK value of #51B366?

#51B366 converts to approximately cmyk(55%, 0%, 43%, 30%). CMYK output is a mathematical approximation for planning; confirm production print colors with your printer and ICC profile.

Should text on #51B366 be black or white?

Black text is the more readable choice. #51B366 scores 2.63:1 against white and 7.99:1 against black, and WCAG 2.2 asks for at least 4.5:1 for normal body text.

Can I write #51B366 as a CSS color keyword?

No. #51B366 is not one of the CSS color keywords, so it has to be written as a hex, rgb() or hsl() value. The closest keyword is mediumseagreen (#3CB371) at a CIE76 distance of 7.25, which is clearly related but distinguishable side by side.

Open #51B366 in a Tool

Hex to RGB Hex to HSL Hex to CMYK Hex to OKLCH Hex to Pantone Build a palette Make a gradient

Keep exploring: every green in the color library, the guide to shades of green, or the full color library.