Buttercup Hex Code — #F9E915

The hex color code for Buttercup is #F9E915. In CSS, apply it as text color with color: #F9E915;, as a background with background-color: #F9E915;, or as a border with border-color: #F9E915;. Hex is the most widely used color notation on the web because it is compact, supported by every browser, and easy to copy between design tools like Figma, Photoshop, and code editors.

Buttercup in RGB is rgb(249, 233, 21), where Red=249, Green=233, and Blue=21 on a 0-255 scale. Use RGB when you need transparency — rgba(249, 233, 21, 0.5) creates a 50% transparent version. RGB is also the native format for HTML canvas, WebGL, and JavaScript image manipulation, since each channel represents the intensity of that primary light color on screen displays.

Buttercup can be applied in CSS using multiple formats: (1) Hex: color: #F9E915; — most compact and widely used. (2) RGB: color: rgb(249, 233, 21); — useful when calculating colors dynamically in JavaScript. (3) HSL: color: hsl(56, 95%, 53%); — best for creating variations, since adjusting lightness produces lighter or darker shades while keeping the same hue. (4) With transparency: rgba(249, 233, 21, 0.8); or hsla(56, 95%, 53%, 0.8); for 80% opacity overlays.

Buttercup in HSL is hsl(56, 95%, 53%). HSL stands for Hue (56 degrees on the color wheel), Saturation (95% color intensity), and Lightness (53% brightness). HSL is the most intuitive format for designers because you can create harmonious palettes by rotating the hue, generate hover effects by increasing lightness by 10%, and desaturate colors by reducing the S value. This makes Buttercup a medium, vivid warm-toned color.

Buttercup in CMYK is C:0% M:6% Y:92% K:2%. CMYK (Cyan, Magenta, Yellow, Key/Black) is the standard color model for professional printing — business cards, brochures, merchandise, and packaging. When designing for print in Adobe InDesign or Illustrator, use these exact CMYK values to ensure accurate color reproduction. Screen colors (RGB) often appear more vibrant than their printed CMYK equivalents, so always request a physical proof for brand-critical materials.

Yellow works best as an accent paired with dark backgrounds (charcoal, navy). For warnings and notifications, combine yellow backgrounds with black text for maximum readability.

Pure yellow on white is nearly invisible. Yellow backgrounds need dark text (black or very dark gray) to be readable. For yellow accents, ensure a minimum 3:1 contrast ratio against the surrounding background. For Buttercup specifically: as a medium shade (lightness: 53%), it works best as a background color with dark text overlaid, or as a decorative accent. Avoid using it as text color on white backgrounds since the contrast ratio is likely insufficient. WCAG 2.1 requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text (18px+ bold or 24px+ regular).