656
votes

How to convert colors in RGB format to hex format and vice versa?

For example, convert '#0080C0' to (0, 128, 192).

30
Here' are functions for RGB<->Hex conversation, Average of 2 hex colors, and Random hex color.ashleedawg

30 Answers

1410
votes

Note: both versions of rgbToHex expect integer values for r, g and b, so you'll need to do your own rounding if you have non-integer values.

The following will do to the RGB to hex conversion and add any required zero padding:

function componentToHex(c) {
  var hex = c.toString(16);
  return hex.length == 1 ? "0" + hex : hex;
}

function rgbToHex(r, g, b) {
  return "#" + componentToHex(r) + componentToHex(g) + componentToHex(b);
}

alert(rgbToHex(0, 51, 255)); // #0033ff

Converting the other way:

function hexToRgb(hex) {
  var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  return result ? {
    r: parseInt(result[1], 16),
    g: parseInt(result[2], 16),
    b: parseInt(result[3], 16)
  } : null;
}

alert(hexToRgb("#0033ff").g); // "51";

Finally, an alternative version of rgbToHex(), as discussed in @casablanca's answer and suggested in the comments by @cwolves:

function rgbToHex(r, g, b) {
  return "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
}

alert(rgbToHex(0, 51, 255)); // #0033ff

Update 3 December 2012

Here's a version of hexToRgb() that also parses a shorthand hex triplet such as "#03F":

function hexToRgb(hex) {
  // Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
  var shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
  hex = hex.replace(shorthandRegex, function(m, r, g, b) {
    return r + r + g + g + b + b;
  });

  var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  return result ? {
    r: parseInt(result[1], 16),
    g: parseInt(result[2], 16),
    b: parseInt(result[3], 16)
  } : null;
}

alert(hexToRgb("#0033ff").g); // "51";
alert(hexToRgb("#03f").g); // "51";
159
votes

An alternative version of hexToRgb:

function hexToRgb(hex) {
    var bigint = parseInt(hex, 16);
    var r = (bigint >> 16) & 255;
    var g = (bigint >> 8) & 255;
    var b = bigint & 255;

    return r + "," + g + "," + b;
}

Edit: 3/28/2017 Here is another approach that seems to be even faster

function hexToRgbNew(hex) {
  var arrBuff = new ArrayBuffer(4);
  var vw = new DataView(arrBuff);
  vw.setUint32(0,parseInt(hex, 16),false);
  var arrByte = new Uint8Array(arrBuff);

  return arrByte[1] + "," + arrByte[2] + "," + arrByte[3];
}

Edit: 8/11/2017 The new approach above after more testing is not faster :(. Though it is a fun alternate way.

95
votes

ECMAScript 6 version of Tim Down's answer

Converting RGB to hex

const rgbToHex = (r, g, b) => '#' + [r, g, b].map(x => {
  const hex = x.toString(16)
  return hex.length === 1 ? '0' + hex : hex
}).join('')

console.log(rgbToHex(0, 51, 255)); // '#0033ff'

Converting hex to RGB

Returns an array [r, g, b]. Works also with shorthand hex triplets such as "#03F".

const hexToRgb = hex =>
  hex.replace(/^#?([a-f\d])([a-f\d])([a-f\d])$/i
             ,(m, r, g, b) => '#' + r + r + g + g + b + b)
    .substring(1).match(/.{2}/g)
    .map(x => parseInt(x, 16))

console.log(hexToRgb("#0033ff")) // [0, 51, 255]
console.log(hexToRgb("#03f")) // [0, 51, 255]

Bonus: RGB to hex using padStart() method

const rgbToHex = (r, g, b) => '#' + [r, g, b]
  .map(x => x.toString(16).padStart(2, '0')).join('')

console.log(rgbToHex(0, 51, 255)); // '#0033ff'

Note that this answer uses latest ECMAScript features, which are not supported in older browsers. If you want this code to work in all environments, you should use Babel to compile your code.

47
votes

Here's my version:

function rgb_to_hex(red, green, blue) {
  const rgb = (red << 16) | (green << 8) | (blue << 0);
  return '#' + (0x1000000 + rgb).toString(16).slice(1);
}

function hex_to_rgb(hex) {
  const normal = hex.match(/^#([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})$/i);
  if (normal) return normal.slice(1).map(e => parseInt(e, 16));
  const shorthand = hex.match(/^#([0-9a-f])([0-9a-f])([0-9a-f])$/i);
  if (shorthand) return shorthand.slice(1).map(e => 0x11 * parseInt(e, 16));
  return null;
}
28
votes
function hex2rgb(hex) {
  return ['0x' + hex[1] + hex[2] | 0, '0x' + hex[3] + hex[4] | 0, '0x' + hex[5] + hex[6] | 0];
}
26
votes

I'm assuming you mean HTML-style hexadecimal notation, i.e. #rrggbb. Your code is almost correct, except you've got the order reversed. It should be:

var decColor = red * 65536 + green * 256 + blue;

Also, using bit-shifts might make it a bit easier to read:

var decColor = (red << 16) + (green << 8) + blue;
22
votes

One-line functional HEX to RGBA

Supports both short #fff and long #ffffff forms.
Supports alpha channel (opacity).
Does not care if hash specified or not, works in both cases.

function hexToRGBA(hex, opacity) {
    return 'rgba(' + (hex = hex.replace('#', '')).match(new RegExp('(.{' + hex.length/3 + '})', 'g')).map(function(l) { return parseInt(hex.length%2 ? l+l : l, 16) }).concat(isFinite(opacity) ? opacity : 1).join(',') + ')';
}

examples:

hexToRGBA('#fff')        ->  rgba(255,255,255,1)  
hexToRGBA('#ffffff')     ->  rgba(255,255,255,1)  
hexToRGBA('#fff', .2)    ->  rgba(255,255,255,0.2)  
hexToRGBA('#ffffff', .2) ->  rgba(255,255,255,0.2)  
hexToRGBA('fff', .2)     ->  rgba(255,255,255,0.2)  
hexToRGBA('ffffff', .2)  ->  rgba(255,255,255,0.2)

hexToRGBA('#ffffff', 0)  ->  rgba(255,255,255,0)
hexToRGBA('#ffffff', .5) ->  rgba(255,255,255,0.5)
hexToRGBA('#ffffff', 1)  ->  rgba(255,255,255,1)
20
votes

This code accept #fff and #ffffff variants and opacity.

function hex2rgb(hex, opacity) {
        var h=hex.replace('#', '');
        h =  h.match(new RegExp('(.{'+h.length/3+'})', 'g'));

        for(var i=0; i<h.length; i++)
            h[i] = parseInt(h[i].length==1? h[i]+h[i]:h[i], 16);

        if (typeof opacity != 'undefined')  h.push(opacity);

        return 'rgba('+h.join(',')+')';
}
16
votes

Try (bonus)

let hex2rgb= c=> `rgb(${c.match(/\w\w/g).map(x=>+`0x${x}`)})`
let rgb2hex=c=>'#'+c.match(/\d+/g).map(x=>(+x).toString(16).padStart(2,0)).join``

let hex2rgb= c=> `rgb(${c.match(/\w\w/g).map(x=>+`0x${x}`)})`;
let rgb2hex= c=> '#'+c.match(/\d+/g).map(x=>(+x).toString(16).padStart(2,0)).join``;

// TEST
console.log('#0080C0          -->', hex2rgb('#0080C0'));
console.log('rgb(0, 128, 192) -->', rgb2hex('rgb(0, 128, 192)'));
12
votes

Bitwise solution normally is weird. But in this case I guess that is more elegant 😄

function hexToRGB(hexColor){
  return {
    red: (hexColor >> 16) & 0xFF,
    green: (hexColor >> 8) & 0xFF,  
    blue: hexColor & 0xFF,
  }
}

Usage:

const {red, green, blue } = hexToRGB(0xFF00FF)

console.log(red) // 255
console.log(green) // 0
console.log(blue) // 255
11
votes

This could be used for getting colors from computed style propeties:

function rgbToHex(color) {
    color = ""+ color;
    if (!color || color.indexOf("rgb") < 0) {
        return;
    }

    if (color.charAt(0) == "#") {
        return color;
    }

    var nums = /(.*?)rgb\((\d+),\s*(\d+),\s*(\d+)\)/i.exec(color),
        r = parseInt(nums[2], 10).toString(16),
        g = parseInt(nums[3], 10).toString(16),
        b = parseInt(nums[4], 10).toString(16);

    return "#"+ (
        (r.length == 1 ? "0"+ r : r) +
        (g.length == 1 ? "0"+ g : g) +
        (b.length == 1 ? "0"+ b : b)
    );
}

// not computed 
<div style="color: #4d93bc; border: 1px solid red;">...</div> 
// computed 
<div style="color: rgb(77, 147, 188); border: 1px solid rgb(255, 0, 0);">...</div>

console.log( rgbToHex(color) ) // #4d93bc
console.log( rgbToHex(borderTopColor) ) // #ff0000

Ref: https://github.com/k-gun/so/blob/master/so_util.js

9
votes

(2017) SIMPLE ES6 composable arrow functions

I can't resist sharing this for those who may be writing some modern functional/compositional js using ES6. Here are some slick one-liners I am using in a color module that does color interpolation for data visualization.

Note that this does not handle the alpha channel at all.

const arrayToRGBString = rgb => `rgb(${rgb.join(',')})`;
const hexToRGBArray = hex => hex.match(/[A-Za-z0-9]{2}/g).map(v => parseInt(v, 16));
const rgbArrayToHex = rgb => `#${rgb.map(v => v.toString(16).padStart(2, '0')).join('')}`;
const rgbStringToArray = rgb => rgb.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/).splice(1, 3)
  .map(v => Number(v));
const rgbStringToHex = rgb => rgbArrayToHex(rgbStringToArray(rgb));

BTW, If you like this style/syntax, I wrote a full color module (modern-color) you can grab from npm. I made it so I could use prop getters for conversion and parse virtually anything (Color.parse(anything)). Worth a look if you deal with color a lot like I do.

6
votes

// Ignoring hsl notation, color values are commonly expressed as names, rgb, rgba or hex-

// Hex can be 3 values or 6.

// Rgb can be percentages as well as integer values.

// Best to account for all of these formats, at least.

String.prototype.padZero= function(len, c){
    var s= this, c= c || "0", len= len || 2;
    while(s.length < len) s= c + s;
    return s;
}
var colors={
    colornames:{
        aqua: '#00ffff', black: '#000000', blue: '#0000ff', fuchsia: '#ff00ff',
        gray: '#808080', green: '#008000', lime: '#00ff00', maroon: '#800000',
        navy: '#000080', olive: '#808000', purple: '#800080', red: '#ff0000',
        silver: '#c0c0c0', teal: '#008080', white: '#ffffff', yellow: '#ffff00'
    },
    toRgb: function(c){
        c= '0x'+colors.toHex(c).substring(1);
        c= [(c>> 16)&255, (c>> 8)&255, c&255];
        return 'rgb('+c.join(',')+')';
    },
    toHex: function(c){
        var tem, i= 0, c= c? c.toString().toLowerCase(): '';
        if(/^#[a-f0-9]{3,6}$/.test(c)){
            if(c.length< 7){
                var A= c.split('');
                c= A[0]+A[1]+A[1]+A[2]+A[2]+A[3]+A[3];
            }
            return c;
        }
        if(/^[a-z]+$/.test(c)){
            return colors.colornames[c] || '';
        }
        c= c.match(/\d+(\.\d+)?%?/g) || [];
        if(c.length<3) return '';
        c= c.slice(0, 3);
        while(i< 3){
            tem= c[i];
            if(tem.indexOf('%')!= -1){
                tem= Math.round(parseFloat(tem)*2.55);
            }
            else tem= parseInt(tem);
            if(tem< 0 || tem> 255) c.length= 0;
            else c[i++]= tem.toString(16).padZero(2);
        }
        if(c.length== 3) return '#'+c.join('').toLowerCase();
        return '';
    }
}
//var c='#dc149c';
//var c='rgb(100%,25%,0)';
//
var c= 'red';
alert(colors.toRgb(c)+'\n'+colors.toHex(c));
5
votes

@ Tim, to add to your answer (its a little awkward fitting this into a comment).

As written, I found the rgbToHex function returns a string with elements after the point and it requires that the r, g, b values fall within the range 0-255.

I'm sure this may seem obvious to most, but it took two hours for me to figure out and by then the original method had ballooned to 7 lines before I realised my problem was elsewhere. So in the interests of saving others time & hassle, here's my slightly amended code that checks the pre-requisites and trims off the extraneous bits of the string.

function rgbToHex(r, g, b) {
    if(r < 0 || r > 255) alert("r is out of bounds; "+r);
    if(g < 0 || g > 255) alert("g is out of bounds; "+g);
    if(b < 0 || b > 255) alert("b is out of bounds; "+b);
    return "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1,7);
}
4
votes

If you need compare two color values (given as RGB, name color or hex value) or convert to HEX use HTML5 canvas object.

var canvas = document.createElement("canvas");
var ctx = this.canvas.getContext('2d');

ctx.fillStyle = "rgb(pass,some,value)";
var temp =  ctx.fillStyle;
ctx.fillStyle = "someColor";

alert(ctx.fillStyle == temp);
3
votes

May you be after something like this?

function RGB2HTML(red, green, blue)
{
    return '#' + red.toString(16) +
           green.toString(16) +
           blue.toString(16);
}

alert(RGB2HTML(150, 135, 200));

displays #9687c8

2
votes

Shorthand version that accepts a string:

function rgbToHex(a){
  a=a.replace(/[^\d,]/g,"").split(","); 
  return"#"+((1<<24)+(+a[0]<<16)+(+a[1]<<8)+ +a[2]).toString(16).slice(1)
}

document.write(rgbToHex("rgb(255,255,255)"));

To check if it's not already hexadecimal

function rgbToHex(a){
  if(~a.indexOf("#"))return a;
  a=a.replace(/[^\d,]/g,"").split(","); 
  return"#"+((1<<24)+(+a[0]<<16)+(+a[1]<<8)+ +a[2]).toString(16).slice(1)
}

document.write("rgb: "+rgbToHex("rgb(255,255,255)")+ " -- hex: "+rgbToHex("#e2e2e2"));
2
votes

Instead of copy'n'pasting snippets found here and there, I'd recommend to use a well tested and maintained library: Colors.js (available for node.js and browser). It's just 7 KB (minified, gzipped even less).

1
votes

For 3 digits hexToRgb function of Tim Down can be improved as below:

var hex2Rgb = function(hex){
  var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})|([a-f\d]{1})([a-f\d]{1})([a-f\d]{1})$/i.exec(hex);
  return result ? {        
    r: parseInt(hex.length <= 4 ? result[4]+result[4] : result[1], 16),
    g: parseInt(hex.length <= 4 ? result[5]+result[5] : result[2], 16),
    b: parseInt(hex.length <= 4 ? result[6]+result[6] : result[3], 16),
    toString: function() {
      var arr = [];
      arr.push(this.r);
      arr.push(this.g);
      arr.push(this.b);
      return "rgb(" + arr.join(",") + ")";
    }
  } : null;
};
1
votes

i needed a function that accepts invalid values too like

rgb(-255, 255, 255) rgb(510, 255, 255)

this is a spin off of @cwolves answer

function rgb(r, g, b) {
  this.c = this.c || function (n) {
    return Math.max(Math.min(n, 255), 0)
  };

  return ((1 << 24) + (this.c(r) << 16) + (this.c(g) << 8) + this.c(b)).toString(16).slice(1).toUpperCase();
}
1
votes
R = HexToR("#FFFFFF");
G = HexToG("#FFFFFF");
B = HexToB("#FFFFFF");

function HexToR(h) {return parseInt((cutHex(h)).substring(0,2),16)}
function HexToG(h) {return parseInt((cutHex(h)).substring(2,4),16)}
function HexToB(h) {return parseInt((cutHex(h)).substring(4,6),16)}
function cutHex(h) {return (h.charAt(0)=="#") ? h.substring(1,7):h}

Use these Function to achive the result without any issue. :)

1
votes

While this answer is unlikely to fit the question perfectly it may be very useful none the less.

  1. Create any random element

var toRgb = document.createElement('div');

  1. Set any valid style to the color you want to convert

toRg.style.color = "hsl(120, 60%, 70%)";

  1. Call the style property again

> toRgb.style.color;

< "rgb(133, 225, 133)" Your color has been converted to Rgb

Works for: Hsl, Hex

Does not work for: Named colors

1
votes

My version of hex2rbg:

  1. Accept short hex like #fff
  2. Algorithm compacity is o(n), should faster than using regex. e.g String.replace, String.split, String.match etc..
  3. Use constant space.
  4. Support rgb and rgba.

you may need remove hex.trim() if you are using IE8.

e.g.

hex2rgb('#fff') //rgb(255,255,255) 
hex2rgb('#fff', 1) //rgba(255,255,255,1) 
hex2rgb('#ffffff') //rgb(255,255,255)  
hex2rgb('#ffffff', 1) //rgba(255,255,255,1)

code:

function hex2rgb (hex, opacity) {
    hex = hex.trim();
    hex = hex[0] === '#' ? hex.substr(1) : hex;
    var bigint = parseInt(hex, 16), h = [];
    if (hex.length === 3) {
        h.push((bigint >> 4) & 255);
        h.push((bigint >> 2) & 255);
    } else {
        h.push((bigint >> 16) & 255);
        h.push((bigint >> 8) & 255);
    }
    h.push(bigint & 255);
    if (arguments.length === 2) {
        h.push(opacity);
        return 'rgba('+h.join()+')';
    } else {
        return 'rgb('+h.join()+')';
    }
}
1
votes

This snippet converts hex to rgb and rgb to hex.

View demo

function hexToRgb(str) { 
    if ( /^#([0-9a-f]{3}|[0-9a-f]{6})$/ig.test(str) ) { 
        var hex = str.substr(1);
        hex = hex.length == 3 ? hex.replace(/(.)/g, '$1$1') : hex;
        var rgb = parseInt(hex, 16);               
        return 'rgb(' + [(rgb >> 16) & 255, (rgb >> 8) & 255, rgb & 255].join(',') + ')';
    } 

    return false; 
}

function rgbToHex(red, green, blue) {
    var out = '#';

    for (var i = 0; i < 3; ++i) {
        var n = typeof arguments[i] == 'number' ? arguments[i] : parseInt(arguments[i]);

        if (isNaN(n) || n < 0 || n > 255) {
            return false;
        }

        out += (n < 16 ? '0' : '') + n.toString(16);
    }
    return out
}
1
votes

A simple answer for rgb to hex

    function rgbtohex(r,g,b){
        return "#" + (Math.round(r) * 65536 + Math.round(g) * 256 + Math.round(b)).toString(16));
    }
1
votes

I came across this problem since I wanted to parse any color string value and be able to specify an opacity, so I wrote this function that uses the canvas API.

var toRGBA = function () {
  var canvas = document.createElement('canvas');
  var context = canvas.getContext('2d');

  canvas.width = 1;
  canvas.height = 1;

  return function (color) {
    context.fillStyle = color;
    context.fillRect(0, 0, 1, 1);

    var data = context.getImageData(0, 0, 1, 1).data;

    return {
      r: data[0],
      g: data[1],
      b: data[2],
      a: data[3]
    };
  };
}();

Note about context.fillStyle:

If parsing the value results in failure, then it must be ignored, and the attribute must retain its previous value.

Here's a Stack Snippet demo you can use to test inputs:

var toRGBA = function () {
  var canvas = document.createElement('canvas');
  var context = canvas.getContext('2d');

  canvas.width = 1;
  canvas.height = 1;

  return function (color) {
    context.fillStyle = color;
    context.fillRect(0, 0, 1, 1);

    var data = context.getImageData(0, 0, 1, 1).data;

    return {
      r: data[0],
      g: data[1],
      b: data[2],
      a: data[3]
    };
  };
}();

var inputs = document.getElementsByTagName('input');

function setColor() {
  inputs[1].value = JSON.stringify(toRGBA(inputs[0].value));
  document.body.style.backgroundColor = inputs[0].value;
}

inputs[0].addEventListener('input', setColor);
setColor();
input {
  width: 200px;
  margin: 0.5rem;
}
<input value="cyan" />
<input readonly="readonly" />
1
votes

2021 version

You can simply use rgb-hex & hex-rgb as it is battle-tested & has multiple options that are not available in other solutions.

I was recently building a Color Picker & these 2 packages came in handy.

Usage

rgb-hex

import rgbHex from 'rgb-hex';

rgbHex(65, 131, 196);
//=> '4183c4'

rgbHex('rgb(40, 42, 54)');
//=> '282a36'

rgbHex(65, 131, 196, 0.2);
//=> '4183c433'

rgbHex(40, 42, 54, '75%');
//=> '282a36bf'

rgbHex('rgba(40, 42, 54, 75%)');
//=> '282a36bf'

hex-rgb

import hexRgb from 'hex-rgb';

hexRgb('4183c4');
//=> {red: 65, green: 131, blue: 196, alpha: 1}

hexRgb('#4183c4');
//=> {red: 65, green: 131, blue: 196, alpha: 1}

hexRgb('#fff');
//=> {red: 255, green: 255, blue: 255, alpha: 1}

hexRgb('#22222299');
//=> {red: 34, green: 34, blue: 34, alpha: 0.6}

hexRgb('#0006');
//=> {red: 0, green: 0, blue: 0, alpha: 0.4}

hexRgb('#cd2222cc');
//=> {red: 205, green: 34, blue: 34, alpha: 0.8}

hexRgb('#cd2222cc', {format: 'array'});
//=> [205, 34, 34, 0.8]

hexRgb('#cd2222cc', {format: 'css'});
//=> 'rgb(205 34 34 / 80%)'

hexRgb('#000', {format: 'css'});
//=> 'rgb(0 0 0)'

hexRgb('#22222299', {alpha: 1});
//=> {red: 34, green: 34, blue: 34, alpha: 1}

hexRgb('#fff', {alpha: 0.5});
//=> {red: 255, green: 255, blue: 255, alpha: 0.5}
0
votes

I'm working with XAML data that has a hex format of #AARRGGBB (Alpha, Red, Green, Blue). Using the answers above, here's my solution:

function hexToRgba(hex) {
    var bigint, r, g, b, a;
    //Remove # character
    var re = /^#?/;
    var aRgb = hex.replace(re, '');
    bigint = parseInt(aRgb, 16);

    //If in #FFF format
    if (aRgb.length == 3) {
        r = (bigint >> 4) & 255;
        g = (bigint >> 2) & 255;
        b = bigint & 255;
        return "rgba(" + r + "," + g + "," + b + ",1)";
    }

    //If in #RRGGBB format
    if (aRgb.length >= 6) {
        r = (bigint >> 16) & 255;
        g = (bigint >> 8) & 255;
        b = bigint & 255;
        var rgb = r + "," + g + "," + b;

        //If in #AARRBBGG format
        if (aRgb.length == 8) {
            a = ((bigint >> 24) & 255) / 255;
            return "rgba(" + rgb + "," + a.toFixed(1) + ")";
        }
    }
    return "rgba(" + rgb + ",1)";
}

http://jsfiddle.net/kvLyscs3/

0
votes

For convert directly from jQuery you can try:

  function rgbToHex(color) {
    var bg = color.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);
    function hex(x) {
      return ("0" + parseInt(x).toString(16)).slice(-2);
    }
    return     "#" + hex(bg[1]) + hex(bg[2]) + hex(bg[3]);
  }

  rgbToHex($('.col-tab-bar .col-tab span').css('color'))
0
votes
function getRGB(color){
  if(color.length == 7){
    var r = parseInt(color.substr(1,2),16);
    var g = parseInt(color.substr(3,2),16);
    var b = parseInt(color.substr(5,2),16);    
    return 'rgb('+r+','+g+','+b+')' ;
  }    
  else
    console.log('Enter correct value');
}
var a = getRGB('#f0f0f0');
if(!a){
 a = 'Enter correct value'; 
}

a;