How to Pick and Convert Colors Online (HEX, RGB, HSL)
Every digital design decision eventually comes down to a color value — and that value needs to exist in the right format for the tool or environment you are working in. A CSS stylesheet might need oklch, a design handoff might reference RGB, and a brand guideline PDF specifies HEX. Converting between these formats manually using formulas is tedious and error-prone. An online color picker solves this instantly: click your color, sample it from an image, or type a known value, and all equivalent formats appear side by side in real time. This article walks through how to use a color picker effectively and when each format matters.
Using the Visual Color Picker
The core of any color picker tool is the visual selector — a two-dimensional gradient canvas where you drag a crosshair to choose a color, paired with a hue slider that moves through the spectrum from red to violet and back to red. The two-dimensional canvas represents saturation on one axis and lightness or value on the other. Dragging the crosshair toward the top-right gives you the most saturated, fully bright version of the selected hue. Dragging toward the bottom-right gives a dark, saturated shade. Dragging toward the left desaturates the color, approaching gray or white depending on the vertical position. The hue slider (usually displayed as a horizontal rainbow bar) sets the base color family. At 0 degrees you have red; at 120 degrees, green; at 240 degrees, blue. Intermediate values give you orange, yellow, cyan, and all the hues between. Most color pickers also include an opacity (alpha) slider. Setting alpha below 100% produces a color with transparency, expressed in RGBA or HSLA notation. A fully opaque color is alpha 1.0 (or 255 in 0-255 notation). Once you have selected a color visually, the tool shows its values in all supported formats: HEX, RGB, HSL, and oklch. You can also type directly into any of the format input fields — type a known HEX value and the visual picker jumps to that color, and all other formats update immediately. The WikiPlus Color Picker additionally lets you sample colors from images. Upload an image, hover over any pixel, and the tool reads the precise color at that position. This is the fastest way to extract a brand color from a logo or a palette from a reference photo.
When to Use HEX, RGB, HSL, or oklch
Each color format has strengths that make it the natural choice in certain contexts. HEX (#RRGGBB or #RGB): the most universally recognized format in web development. Every design tool, browser, and CSS validator accepts HEX. It is compact and easy to copy-paste. Use HEX when sharing color values between tools, in design specifications, or when copy-pasting into a codebase that already uses HEX. RGB (rgb(255, 99, 71)): expresses colors as red, green, and blue components on a 0–255 scale. It maps directly to how displays work — every pixel mixes these three channels. Use RGB when working with canvas APIs, image processing, or any system that expects numeric components. RGBA extends this with an alpha channel for transparency. HSL (hsl(9, 100%, 64%)): describes color as hue (0–360 degree angle on the color wheel), saturation (0–100%), and lightness (0–100%). HSL is the most intuitive format for designers because adjusting lightness to create a tint or shade is a single slider change. Use HSL in CSS custom properties when you want to programmatically lighten, darken, or desaturate a base color. CSS functions like calc() can adjust HSL values, enabling theming systems. oklch (oklch(0.63 0.22 29)): a perceptually uniform color space where equal numeric changes in lightness produce equal perceived changes in brightness across all hue families. This is a significant advantage over HSL, where equal lightness adjustments produce perceptually unequal results across hues. oklch is supported in all modern browsers (Chrome 111+, Firefox 113+, Safari 15.4+) and is the recommended format in modern CSS for design tokens and dynamic color generation. For most projects in 2026, using oklch for design tokens and HEX for static color values in documentation is a practical combination.
Sampling Colors From Images
Extracting exact colors from images is one of the most frequently needed tasks in design and development. Whether you are matching a client's brand color from their logo, building a color palette inspired by a photograph, or identifying the precise shade used in a competitor's UI, image color sampling saves time and eliminates guesswork. The WikiPlus Color Picker's image sampler lets you upload any JPEG, PNG, WebP, or SVG image. Once uploaded, hover over any area of the image and the tool reads the color at that pixel position, displaying it in all four formats — HEX, RGB, HSL, and oklch — in real time as you move the cursor. Tips for accurate sampling: — Sample from a solid area of the color, not near edges where anti-aliasing blends colors. Edges between a colored shape and a white background will show a mixed intermediate color. — Zoom into the image before sampling small design elements. At high zoom, you can position the cursor with pixel precision. — For logo colors, use the original vector or high-resolution file rather than a screenshot or small thumbnail. JPG compression and image scaling both alter pixel colors from the original. — Sample multiple nearby pixels if the color looks mottled. Calculate an average or identify the most representative pixel. A practical workflow for brand color extraction: upload the official logo, sample the primary, secondary, and accent colors, copy each HEX value, and document them in your project's design token file. This creates a definitive reference that prevents color drift across the project as different team members use different tools.
WCAG Contrast Checking in the Color Picker
Web Content Accessibility Guidelines (WCAG) require sufficient contrast between text and its background to ensure readability for users with low vision or color blindness. The WCAG contrast ratio is a number from 1:1 (no contrast, identical colors) to 21:1 (maximum contrast, black on white). Required ratios: — WCAG AA: 4.5:1 for normal text, 3:1 for large text (18pt or 14pt bold) — WCAG AAA: 7:1 for normal text, 4.5:1 for large text The WikiPlus Color Picker includes a built-in contrast checker. Select a foreground color and a background color, and the tool calculates and displays the contrast ratio, along with a pass/fail indicator for AA and AAA at both normal and large text sizes. How to use it: pick your text color first, then input your background color in the second field. The ratio updates in real time as you adjust either color. If the ratio fails, try adjusting the lightness of one of the colors until you pass. Common contrast failures: — Light gray text on white backgrounds (#aaaaaa on #ffffff is about 2.3:1 — fails AA) — Pastel text on light backgrounds — both have similar lightness values — Yellow text on white — high saturation but low contrast — Green on red — distinguishable to most people by hue, but similar luminance makes them fail contrast The contrast ratio formula uses relative luminance, which is a weighted combination of the R, G, and B channels that accounts for human perception. Blue contributes much less to perceived brightness than green, so a bright blue and a medium green may have very different luminance values despite both appearing 'bright.' For a complete accessibility color workflow: choose your primary brand color, then use the contrast checker to find a text color and background combination that passes AA at minimum. Lock those values as design tokens before distributing them to your team.
Frequently Asked Questions
- What is the difference between HEX and RGB color formats?
- HEX and RGB express the same color information — red, green, and blue channel intensities — in different notations. RGB uses decimal integers from 0 to 255 for each channel: rgb(255, 99, 71). HEX uses two hexadecimal digits per channel, prefixed with #: #FF6347. They are mathematically equivalent, and the Color Picker converts between them instantly. Use RGB when working with canvas APIs or image processing code that expects numeric values. Use HEX when copy-pasting colors in design tools, CSS files, and documentation, where its compact, single-string format is most convenient.
- Can I pick a color from my screen, not just from an image?
- Modern browsers support the EyeDropper API, which lets a web-based color picker sample any color visible on the screen — including from other browser tabs, images, or native OS windows. If your browser supports it (Chrome 95+, Edge 95+), the WikiPlus Color Picker activates this feature via the eyedropper button. Clicking the button turns your cursor into a magnifier; click anywhere on screen to sample that pixel's color. Safari and Firefox have limited support as of early 2026, so for those browsers, uploading an image and sampling from it is the reliable alternative.
- What is oklch and why should I use it in CSS?
- oklch is a perceptually uniform color space introduced to CSS in 2023. The key advantage over HSL or HEX is that adjusting the lightness value in oklch produces equal perceived brightness changes across all hue families — which HSL does not. In HSL, a yellow at 90% lightness appears much brighter than a blue at 90% lightness. In oklch, equal lightness values look equally bright across hues. This makes oklch the best choice for design tokens, dynamically generated palettes, and dark mode color calculations. Use it with CSS custom properties for color systems that need to scale reliably across themes.