The main difference between Sky Blue and Royal Blue is hue — Sky Blue is a cool cyan, while Royal Blue is a cool blue. Sky Blue (#87CEEB) has an HSL of 197°, 71%, 73%, whereas Royal Blue (#4169E1) sits at 225°, 73%, 57%.
Sky Blue (#87CEEB) is a light, vivid cyan with a cool undertone — it feels airy, soft, approachable and bright, energetic, eye-catching.
Royal Blue (#4169E1) is a medium, vivid blue with a cool undertone — it feels balanced, versatile and bright, energetic, eye-catching.
Text legibility depends on the contrast ratio between foreground and background. WCAG 2.1 AA requires at least 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1. Use these numbers to choose accessible combinations for your design.
Each color has a dedicated page with shades, tints, CSS name, pairings, and color psychology.