CalcOpenly
한국어

Color code converter (HEX, RGB, HSL, CMYK, OKLCH)

Convert a color from HEX to RGB, HSL, HSV, CMYK, CIE Lab and OKLCH or back, and find its nearest CSS named color and relative luminance.

업데이트 검증한 예제: 6

#RRGGBB, #RGB, a CSS name, rgb(), hsl(), hsv(), cmyk(), oklab(), oklch(), or lab() with the D65 white point.
시도하기
HEX
#2E86C1
HEX: #2E86C1
RGB
rgb(46, 134, 193)
HSL
hsl(204.1, 61.5%, 46.9%)
HSV / HSB
hsv(204.1, 76.2%, 75.7%)
CMYK
cmyk(76.2%, 30.6%, 0.0%, 24.3%)
CIE Lab (D65)
L* 53.47, a* -5.68, b* -38.11
OKLCH
oklch(59.57% 0.1217 242.57)
Nearest CSS named color
steelblue
Distance to that name (ΔE OK)
0.0244
Relative luminance
0.2148

#2E86C1 is hsl(204.1, 61.5%, 46.9%) in HSL: hue 204°, 62% saturation, 47% lightness. The closest CSS name is “steelblue” (#4682B4).

Your color and its nearest name

#2E86C1
rgb(46, 134, 193)
steelblue
#4682B4
계산 방법 S

  1. Scale the channels to 0–1

    R=0.1804, G=0.5255, B=0.7569(46,134,193)÷255R = 0.1804,\ G = 0.5255,\ B = 0.7569\quad(46, 134, 193) \div 255

    Read as hex.

  2. HSL and HSV from the largest and smallest channel

    L=max⁡+min⁡2=0.4686SL=max⁡−Lmin⁡(L, 1−L)=0.6151V=max⁡=0.7569H=204.08∘\begin{aligned} L &= \tfrac{\max + \min}{2} = 0.4686 \\ S_L &= \tfrac{\max - L}{\min(L,\,1-L)} = 0.6151 \\ V &= \max = 0.7569 \\ H &= 204.08^\circ \end{aligned}

  3. CMYK

    K=1−max⁡(R,G,B)=0.2431C=1−R−K1−K=0.7617\begin{aligned} K &= 1 - \max(R,G,B) = 0.2431 \\ C &= \tfrac{1 - R - K}{1 - K} = 0.7617 \end{aligned}

    This is the textbook formula with no ink limit or printer profile.

  4. Linearise, then convert to CIE XYZ (D65)

    (R,G,B)lin=(0.0273,0.2384,0.5333)(X,Y,Z)=(0.1928,0.2148,0.5358)\begin{aligned} (R, G, B)_{lin} &= (0.0273, 0.2384, 0.5333) \\ (X, Y, Z) &= (0.1928, 0.2148, 0.5358) \end{aligned}

    Uses the IEC 61966-2-1 transfer curve and the CSS Color 4 sRGB-to-XYZ matrix.

  5. CIE Lab against the D65 white

    L∗=116f(Y)−16=53.47a∗=500 [f(X/Xn)−f(Y)]=−5.68b∗=200 [f(Y)−f(Z/Zn)]=−38.11\begin{aligned} L^* &= 116 f(Y) - 16 = 53.47 \\ a^* &= 500\,[f(X/X_n) - f(Y)] = -5.68 \\ b^* &= 200\,[f(Y) - f(Z/Z_n)] = -38.11 \end{aligned}

    CSS lab() uses a D50 white instead, so its numbers differ slightly from these D65 values.

  6. OKLab and OKLCH

    (L,a,b)=(0.5957,−0.0560,−0.1080)C=a2+b2=0.1217h=atan2⁡(b,a)=242.57∘\begin{aligned} (L, a, b) &= (0.5957, -0.0560, -0.1080) \\ C &= \sqrt{a^2 + b^2} = 0.1217 \\ h &= \operatorname{atan2}(b, a) = 242.57^\circ \end{aligned}

    LMS cone responses are cube-rooted between Ottosson's two matrices.

  7. Nearest CSS name

    ΔEOK=0.0244 to steelblue (#4682B4)\Delta E_{OK} = 0.0244\ \text{to steelblue } (\text{\#4682B4})

    Distance is the straight-line gap in OKLab. CSS Color 4 treats 0.02 as a just-noticeable difference in its gamut-mapping algorithm.

Color code converter (HEX, RGB, HSL, CMYK, OKLCH) 소개

The converter reads any CSS color notation into sRGB channels between 0 and 1, then derives each format from them: HEX and RGB scale the channels to 0–255, HSL and HSV come from the largest and smallest channel, and CMYK sets K = 1 − max(R, G, B). For CIE Lab and OKLCH it first removes the sRGB gamma curve of IEC 61966-2-1, converts to CIE XYZ with the D65 white point, then applies the CIE 15 and Ottosson (2020) formulas.

Designers and front-end developers use it to move a color between CSS, design tools and print specs. The default, #2E86C1, is rgb(46, 134, 193), hsl(204.1, 61.5%, 46.9%) and oklch(59.57% 0.1217 242.57), and its nearest CSS named color is steelblue (#4682B4).

CMYK here is the plain formula with no printer profile, so a print shop's values will differ.

계산 예제

Steel blue #2E86C1

색상
#2E86C1
RGB
rgb(46, 134, 193)
HSL
hsl(204.1, 61.5%, 46.9%)
HSV / HSB
hsv(204.1, 76.2%, 75.7%)
CMYK
cmyk(76.2%, 30.6%, 0.0%, 24.3%)

검증 출처: Python 3.8 colorsys.rgb_to_hls / rgb_to_hsv on (46, 134, 193)/255, formatted to 1 dp

Pure red

색상
red
HEX
#FF0000
CIE Lab (D65)
L* 53.24, a* 80.09, b* 67.20
OKLCH
oklch(62.80% 0.2577 29.23)
Relative luminance
0.2126

검증 출처: Separate Python 3.8 decimal script of the CIE 15 Lab (D65) and Ottosson OKLab formulas; matches Bruce Lindbloom's sRGB/D65 red (53.24, 80.09, 67.20) and CSS Color 4's oklch(62.8% 0.2577 29.23)

HSL input lands exactly on a named color

색상
hsl(120, 100%, 25.1%)
HEX
#008000
Nearest CSS named color
green

검증 출처: Python 3.8 colorsys.hls_to_rgb(1/3, 0.251, 1.0) × 255 = (0, 128.01, 0) → #008000; CSS Color 4 §6.1 green = #008000

White has no hue (edge)

색상
#fff
HEX
#FFFFFF
HSL
hsl(0.0, 0.0%, 100.0%)
CMYK
cmyk(0.0%, 0.0%, 0.0%, 0.0%)
OKLCH
oklch(100.00% 0.0000 none)
Nearest CSS named color
white

검증 출처: Definition: max = min = 1 gives zero saturation and chroma; CSS Color 4 treats the hue of an achromatic color as powerless (none)

자주 묻는 질문

How do you convert HEX to RGB?

Split the six hex digits into three pairs and convert each pair from base 16 to decimal: #2E86C1 is 2E = 46, 86 = 134 and C1 = 193, so rgb(46, 134, 193). A three-digit shorthand doubles each digit, so #F80 means #FF8800. To go the other way, write each 0–255 channel as two hex digits, padding with a leading 0 below 16.

What is the difference between HSL and HSV?

Both use the same hue angle but define the other two values differently. HSL lightness is the average of the largest and smallest channel, so pure colors sit at 50% and white at 100%; HSV value is the largest channel, so pure colors sit at 100%. #2E86C1 is hsl(204.1, 61.5%, 46.9%) but hsv(204.1, 76.2%, 75.7%). CSS has hsl() and hwb() but no hsv().

Why doesn't my CMYK conversion match what the printer uses?

A plain conversion only rearranges screen RGB: K = 1 − max(R, G, B) and each ink is (1 − channel − K) ÷ (1 − K), with no knowledge of paper, ink or press. Print workflows convert through an ICC profile such as FOGRA39 or GRACoL 2006, which limits total ink coverage and shifts colors, so treat these numbers as a starting point and ask the printer for their profile.

What is OKLCH and why use it in CSS?

OKLCH is the polar form of Björn Ottosson's 2020 OKLab space: lightness L, chroma C and hue h. Equal steps in L look about equally different in brightness across hues, which HSL does not manage, so it suits palettes and accessible color scales. CSS Color Level 4 defines oklch(), and every major browser has supported it since 2023. Pure red is oklch(62.8% 0.2577 29.23).

What is relative luminance?

Relative luminance is a color's brightness on a scale from 0 (black) to 1 (white), computed on linear channels after removing the sRGB gamma curve: L = 0.2126 R + 0.7152 G + 0.0722 B. Green weighs most because the eye is most sensitive to it, so pure red scores 0.2126 and #2E86C1 scores 0.2148. WCAG uses it for contrast ratios, (L1 + 0.05) ÷ (L2 + 0.05).

“Color code converter (HEX, RGB, HSL, CMYK, OKLCH)”의 정확도는 어느 정도인가요?

정확도는 입력값과 계산 방법의 가정에 따라 달라집니다. 십진 연산은 유효숫자 50자리를 사용하지만, 추정값·수치해석 방법·원본 데이터의 정밀도는 더 낮을 수 있습니다. 표시값을 반올림해도 이러한 한계는 사라지지 않습니다. 독립적인 출처의 풀이와 대조한 계산 예시: 6. 예를 들어 “Steel blue #2E86C1”은 Python 3.8 colorsys.rgb_to_hls / rgb_to_hsv on (46, 134, 193)/255, formatted to 1 dp와 대조해 확인합니다.

이 계산 방법의 출처는 무엇인가요?

W3C CSS Color Module Level 4 — sRGB, HSL, HWB conversions and sample code; IEC 61966-2-1:1999 — Default RGB colour space sRGB; CIE 15:2004 Colorimetry, 3rd ed. — CIELAB (ε = 216/24389, κ = 24389/27); Björn Ottosson (2020), A perceptual color space for image processing (OKLab).

이 계산기 소개

Clin={C/12.92C≤0.04045(C+0.0551.055)2.4otherwiseL∗=116f(Y/Yn)−16\begin{aligned} C_{lin} &= \begin{cases} C/12.92 & C \le 0.04045 \\ \left(\frac{C+0.055}{1.055}\right)^{2.4} & \text{otherwise}\end{cases} \\[4pt] L^* &= 116 f(Y/Y_n) - 16 \end{aligned}

출처

  1. W3C CSS Color Module Level 4 — sRGB, HSL, HWB conversions and sample code
  2. IEC 61966-2-1:1999 — Default RGB colour space sRGB
  3. CIE 15:2004 Colorimetry, 3rd ed. — CIELAB (ε = 216/24389, κ = 24389/27)
  4. Björn Ottosson (2020), A perceptual color space for image processing (OKLab)

출처와 대조하여 검증

이 계산기에는 독립적인 출처에서 답을 얻은 계산 예제가 6개 있습니다. 테스트 모음에서 실행되며 여기에서도 실행할 수 있습니다.

관련 계산기