Picking the right colors for a website is one of the most visible parts of design. The colors set the tone, guide the eye, and make a site feel professional or playful. But behind every color you see on a website, there is a code that the browser uses to render it. A color picker is the bridge between the color you can see and the code your CSS needs.
This article walks through how color values work on the web, how to use a color picker to find exactly the color you want, and how to convert between the different formats that designers and developers use every day.
How Colors Work on the Web
Every color on a screen is made by mixing three primary colors of light: red, green, and blue. By varying how much of each color is present, you can produce any of millions of shades.
The most common ways to write a color value in CSS are HEX, RGB, and HSL.
HEX
HEX colors are six character codes that start with a hash symbol. They look like #FF5733 or #3B82F6. Each pair of characters represents the amount of red, green, and blue, written in hexadecimal (a base 16 number system). FF is the maximum and 00 is the minimum.
HEX is compact, familiar, and easy to copy. It is the most common format in design files and CSS code.
RGB
RGB colors use decimal numbers from 0 to 255 for each channel. They look like rgb(255, 87, 51). The same color in HEX is #FF5733. The two formats represent identical colors, just written differently.
RGB is easier to read at a glance because the numbers are familiar. It is also the only format that easily supports an alpha channel for transparency. The value rgba(255, 87, 51, 0.5) is the same orange but at 50 percent opacity.
HSL
HSL stands for hue, saturation, and lightness. It describes color in a way that matches how people naturally think about it. The hue is the base color on a color wheel (0 to 360 degrees). The saturation is how vivid the color is (0 percent is gray, 100 percent is full color). The lightness is how light or dark it is (0 percent is black, 100 percent is white).
HSL is great for adjusting colors programmatically. To make a color lighter, you can just increase the lightness. To make it more pastel, decrease the saturation. To shift its hue, change the hue value.
Modern formats
Modern CSS also supports HWB, LCH, LAB, and OKLCH, which describe color in even more perceptually accurate ways. These are useful for advanced design systems but are less common in everyday work.
How to Use the DevHexLab Color Picker
Open the Color Picker on DevHexLab. The page shows a large color square with a hue strip below it.
Drag the circle on the color square to pick the shade you want. Move it left for less saturation, right for more. Move it up for lighter, down for darker.
Drag the slider on the hue strip to change the base color. The square updates to show all the variations of that hue.
Below the picker, you will see the same color expressed in HEX, RGB, and HSL. Click the copy icon next to any value to copy it to your clipboard.
If you need transparency, drag the alpha slider. The picker then shows you the alpha aware versions of each format: HEX with alpha (eight characters), RGBA, and HSLA.
Practical Color Workflows
Matching a brand color
If your brand has a primary color defined as a HEX code, paste that HEX into the input. The picker will jump to that color and show its RGB and HSL equivalents. You now have the same color in every format your code might need.
Building a palette
Start by picking your primary brand color. Then use the HSL output as a guide to derive accent colors. Keep the hue similar but change the lightness to get a darker shade for hover states and a lighter shade for backgrounds. This produces palettes that look harmonious because all the colors share a common foundation.
Adjusting opacity
Web design often needs the same color at different opacities for overlays, hover states, and shadows. Pick your base color, then use the alpha slider to get the RGBA value for each opacity step. Common steps are 100, 80, 60, 40, and 20 percent.
Picking accessible text colors
Text needs enough contrast with its background to be readable. Pick your background color, then use the DevHexLab Contrast Checker tool to test a text color against it. WCAG AA requires a contrast ratio of 4.5 to 1 for normal text, or 3 to 1 for large text.
Tips for Choosing Colors That Work
Start with one color
It is much easier to derive a palette from a single starting color than to pick five colors that all need to work together. Pick the main color first, then build the rest of the palette from it.
Use HSL for variations
When you need lighter or darker versions of a color, keep the hue and saturation constant and change only the lightness. You will get a coherent set of shades rather than colors that look only loosely related.
Test on real screens
Colors look different on different monitors, in different lighting, and on phones versus laptops. After picking, test on at least one phone and one laptop screen before committing.
Limit your palette
A typical website only needs four to six colors total: one or two brand colors, two or three neutral grays, and one accent color. More than that becomes hard to use consistently.
Watch out for color blindness
About one in twelve men has some form of color blindness. Do not rely on color alone to convey information. Combine color with shape, icon, or text labels so people can still understand the page if they cannot distinguish certain hues.
Frequently Asked Questions
What is the difference between HEX with six digits and HEX with eight digits?
Six digit HEX represents red, green, and blue. Eight digit HEX adds two extra characters at the end for the alpha channel (opacity). #FF5733 is fully opaque orange. #FF573380 is the same orange at 50 percent opacity.
Does it matter whether I use HEX or RGB?
For solid colors, no. The browser converts them all to the same internal representation. Use whichever format your team prefers and stick with it for consistency.
Can I use named colors like red or skyblue?
CSS has about 140 named colors that work in any browser. They are convenient for prototypes but offer less control than HEX or RGB. Most production code uses HEX or HSL.
What is the best format for a design system?
HSL or modern formats like OKLCH are popular for design systems because they make it easy to define color tokens that scale up and down (for shades and tints) using just one variable.
Make Color Picking Effortless
Picking a color is a creative decision. Translating it into code should not be. Open the DevHexLab Color Picker, drag to the shade you want, and grab the HEX, RGB, or HSL value with one click. Save the result into your design system, paste it into a CSS variable, or hand it off to a developer. The color you see on your screen and the color in your code are now the same.